Rediscovery
of a long-lost Charadrius plover from South-East Asia
By Peter R. Kennerley, David N. Bakewell and Philip D. Round. |
|
|
Note:
This article was originally published in Forktail 20 (2004) the
journal of the Oriental
Bird Club (OBC) and was kindly submitted by Robert
DeCandido.
Please
support the OBC's conservation work by visiting
the OBC website and becoming a member. |
ABSTRACT
Several pale Charadrius plovers associating with Kentish
Plovers Charadrius alexandrinus in Singapore, Malaysia, Thailand
and Vietnam, which were presumed not to resemble any known taxon,
have been recorded since 1993. Evidence is presented which establishes
that these birds are Aegialites [Charadrius] dealbatus, described
by Robert Swinhoe in 1870 as a species distinct from Kentish Plover.
Subsequent confusion has resulted in this name being applied to the
form of Kentish Plover that occurs in abundance in East and South-East
Asia, while the true taxon dealbatus has been overlooked
by almost all subsequent taxonomists, and mistakenly described and
illustrated as Kentish Plover in all studies of this taxon. This paper
suggests that this confusion arose, in part, due to misconceptions
over the appearance of dealbatus, which resulted in many
museum specimens of Kentish Plover from East Asia being incorrectly
identified and erroneously labelled as dealbatus. Swinhoe
did not designate a type specimen when he described dealbatus,
and this was only done in 1896, from a composite series of Swinhoe’s
specimens that comprised two taxa. Here, we formally select and describe
a lectotype of Aegialites [Charadrius] dealbatus from Swinhoe’s
pre-1870 specimens, list all known Swinhoe specimens of the composite
taxa as paralectotypes of Aegialites [Charadrius] dealbatus
and establish which specimens represent this taxon and which are Kentish
Plover. Comparison with other small Charadrius plovers occurring
in South-East Asia establishes the diagnosibilty of dealbatus
as a distinct taxon that differs in aspects of plumage, behaviour,
habitat preference and breeding distribution from the commonly occurring
Kentish Plover in East and South-East Asia. Consistent morphological
differences from Kentish Plover include a larger and heavier bill
with a pale base to the lower mandible, pale pinkish-grey legs, light
sandy-brown upperparts and a longer and more conspicuous wing-bar,
particularly across the primaries. We describe plumage differences
between sexes and age classes, and compare dealbatus with
Kentish and Malaysian Plover C. peronii. The breeding range
remains uncertain but probably lies in coastal South China, and evidence
suggests that dealbatus is allopatric with Kentish Plover,
which breeds in northern China. An investigation to establish the
phylogenetic relationship between dealbatus and other small Charadrius
plovers is currently in progress. If dealbatus proves to
be distinct at the species level, we recommend that the name Charadrius
dealbatus with the English name ‘White-faced Plover’
is adopted. The name Charadrius alexandrinus nihonensis is
available for the larger-billed form of Kentish Plover breeding in
north-eastern Asia. The true taxon dealbatus is believed
to be rare but probably underrecorded |
INTRODUCTION
Kentish Plover Charadrius alexandrinus is a common and familiar
shorebird, breeding on coastal and inland wetlands throughout the
warm temperate regions of Europe, Asia, and northern Africa, and also
in North America and on the west coast of South America. Across its
vast range there is considerable geographical variation, with five
races recognised by del Hoyo et al. (1996). Within Asia,
there is almost universal acceptance that three races of Kentish Plover
occur. As a breeding bird, the nominate race is widespread from southern
and western Europe, and North Africa, east across much of central
Asia to the Nei Mongol Autonomous Region in north-eastern China. In
China, the slightly larger-billed but otherwise similar form, C.
a. dealbatus, is said to breed from the southern coastal provinces
of Hainan, Guangxi and Guangdong, north to Liaoning (Cheng 1987).
It is also generally accepted that C. a. dealbatus breeds
in Japan from Honshu south through Kyushu to the Ryukyu islands (Vaurie
1965, Hayman et al. 1986, del Hoyo et al. 1996).
However, Brazil (1991) referred to the Japanese breeding birds as
belonging to the race C. a. nihonensis. In addition to these
two migratory races, a smaller resident form, C. a. seebohmi,
breeds in the coastal lowlands of Sri Lanka and the southern tip of
peninsular India (Ali and Ripley 1969). A fourth taxon, previously
treated as an insular race of Kentish Plover (Chasen 1938, Hoogerwerf
1967), is now widely recognised as a distinct species, Javan Plover
C. javanicus, (Cramp and Simmons 1983, Inskipp et al.
1996, del Hoyo et al. 1996, Dickinson 2003, Clements
2007). Javan Plover is believed to be resident on Java, but was discovered
to be breeding at Kuala Penet, Lampung, Sumatra, in June 2007 (I.
Londo/WCS in litt. 2008), and may also breed in Sulawesi,
where it is regularly observed (P. Morris in litt. 2007).
Northern populations of Kentish Plover are migratory and winter to
the south of the breeding range. In China, wintering birds remain
as far north as the Yangtze River, and they are common in coastal
regions in the southern coastal provinces of China. Small numbers
also winter in southern Japan, and the species is numerous in winter
from Taiwan, south through the Malay Peninsula to Singapore, as well
as in the Philippines and Borneo (Cheng 1987, Wells 1999, Carey et
al. 2001). Outside the breeding season, Kentish Plover moults
into a drabber plumage, making racial separation of the migratory
taxa problematic at this season.
This paper challenges this long-standing arrangement and presents
evidence which establishes that the Kentish Plovers of eastern Asia,
widely accepted as being C. a. dealbatus, are, in fact, largely
indistinguishable from Kentish Plovers of the nominate form. We shed
new light on the highly distinctive appearance of the taxon dealbatus,
which has been overlooked in the field, confused and mislabelled in
museum collections, and omitted from the published literature since
the nineteenth century. We also comment on the validity of C.
a. nihonensis as a distinct taxon. |
THE
DISCOVERY OF AN UNKNOWN PLOVER
Kentish Plover is a fairly common winter visitor to Singapore, where
small numbers formerly over-wintered on a large land reclamation site
at Tuas. In October 1993, PRK and others observed several small Charadrius
plovers which were distinctly paler than the accompanying Kentish
Plovers. When initially discovered, all were in nondescript non-breeding
plumage and closely resembled Kentish Plover, although they consistently
differed in their conspicuously paler sandy-brown upperparts and paler
greyish or pinkish-brown legs, while in flight the white wing-bar
appeared broader and more noticeable. Furthermore, the structure of
these birds differed slightly from Kentish Plover: they were noticeably
larger-headed and heavier-billed, and slightly longer-legged, particularly
the tibia. Notes and field sketches were made and compared with illustrations
and descriptions of Charadrius plovers in Hayman et al.
(1986), which depicted one paler bird, described as a non-breeding
adult, with the comment ‘...Some, like this individual, may
become faded and worn in tropical winter quarters’. However,
other than noting these apparently minor differences in plumage and
structural characters, no further progress was made towards establishing
their identity until February 1994, despite regular observations throughout
this four-month period.
On 20 February 1994, PRK, together with Angus Lamont, spent several
hours watching the roosting plover flock at Tuas. On this date, many
Kentish Plovers had completed their pre-breeding moult, and with these
were three extremely distinctive plovers, clearly males, that we could
not identify. Like male Kentish Plovers, they showed a dark band across
the fore-crown, an orange cap and dark patches at the sides of the
breast. Unlike male Kentish Plovers, however, the lores were entirely
white and there was only a small, dull spot behind the eye, so the
dark eye appeared isolated within the white facial feathering, and
seemed exceptionally large and conspicuous. The upperparts were pale
sandy-brown, however, like those birds seen earlier in the winter.
With these three males were up to five females with similar pale sandy-brown
upperparts. As well as sharing structural similarities with the males,
these females displayed a warm and fairly bright rufous-brown wash
to the cap, and slightly duller rufousbrown patches at each side of
the breast, and a variable loral line; on some birds this appeared
as a small rufousbrown spot in front of the eye, while on others it
formed a distinct loral line between the bill and eye. Reference to
Hayman et al. (1986) again failed to reveal a plover with
characters that matched these birds.
This plover flock remained at Tuas until 14 March 1994 when the last
bird, a female, was present together with c25 Kentish Plovers. Shortly
after this date, the Kentish Plover flock departed, presumably returning
to their northern breeding areas. Although the Kentish Plover flock
returned to Tuas in the following winter, the paler birds did not
accompany them.
There were no further known or published sightings from Singapore
or elsewhere until October 2006, when DNB noted an unusually pale
Charadrius plover associating with a Kentish Plover on a land reclamation
site at Tanjung Tokong, Pulau Pinang, Malaysia, on 11 October 2006,
which he tentatively identified as a Malaysian Plover C. peronii.
Following discussion with PRK, it was realised that these plovers
could be the same as the birds seen in Singapore. By December 2006,
numbers had increased to c22 Kentish Plovers and no fewer than 12
unusually pale Charadrius plovers. At least five of the latter
birds remained until early March 2007, and during this period DNB
was able to obtain many photographs. As with the Tuas birds, these
birds underwent a pre-breeding body moult and by early February 2007
they had transformed into a distinctive plover displaying a suite
of characters that did not correspond with any taxon described in
the available literature. Furthermore, these images closely matched
the birds that PRK had described and sketched at Tuas almost 13 years
earlier. The last sighting at Tanjung Tokong was of a presumed first-summer
male on 28 March 2007.
Observations of Kentish Plovers throughout their breeding and wintering
ranges in central and northern Asia, combined with observations of
Kentish Plovers of the race C. a. seebohmi in Sri Lanka,
Javan Plover C. javanicus in Java, Indonesia, and Malaysian
Plover in Singapore, Thailand and elsewhere in South-East Asia, have
established that the field characters associated with these taxa differed
significantly from the pale Charadrius plovers observed in
Singapore and Malaysia. |
THE
SEARCH FOR SPECIMENS
Although it was suspected that these pale Charadrius plovers
might prove to be an undescribed taxon, it seemed inconceivable that
such a distinctive plover could have been overlooked in South-East
Asia, which has a long history of bird-related research and shorebird
studies. The possibility that similar birds may have been previously
collected but lie unrecognised in museum collections was investigated.
Raffles Museum of Biodiversity Research, Singapore
PRK examined Kentish Plover specimens held in the Raffles Museum of
Biodiversity Research at the National University of Singapore in early
1994. Here, two birds in non-breeding plumage that resembled the pale
birds seen at Tuas were located. Both were labelled Charadrius
alexandrinus dealbatus by the same unknown collector, and were
collected at Batu, Selangor coast, Malaya [Malaysia], on 26 November
1906. Although both specimens were in non-breeding plumage, they had
been sexed as males. The remaining 16 Kentish Plovers in this collection,
from Japan (1), Sarawak (7), Vietnam (4), Malaysia (1) Singapore (2)
and Thailand (1), were also labelled Charadrius alexandrinus dealbatus,
but were indistinguishable from Kentish Plovers which winter in South-East
Asia. The two pale specimens (specimen reference numbers ZRC 3.2540
and ZRC 3.2541) were sent on loan to the NHM, Tring, in June 2007
for further detailed examination and comparison with Kentish Plover
specimens held in that collection. These specimens are listed in Appendix
1.
Natural History Museum (NHM), Tring, U.K.
Examination of Kentish Plover specimens held in the NHM, Tring, by
PRK revealed no fewer than 30 Charadrius plovers showing
plumage and bare part characters consistent with the pale plovers
observed in Malaysia and Singapore. All were collected at locations
ranging from central Vietnam to coastal southern China. Significantly,
15 of these specimens, collected by Robert Swinhoe prior to 1870,
came from localities along the south coast of China, which Swinhoe
(1870) identified as the type locality for the bird he named Aegialites
dealbatus, (hereafter referred to as ‘Swinhoe’s dealbatus’).
Furthermore, all specimens matching the description of ‘Swinhoe’s
dealbatus’ from the type locality were dated between
the months of March and July, with the sole exception of a bird from
Macau collected on 30 January 1906. With these, however, were a further
20 specimens of typically darker Kentish Plover, also collected by
Swinhoe prior to 1870 from locations in southern China, hereafter
referred to as ‘eastern’ Kentish Plover. All these darker
birds had, however, been collected during the winter months between
October and March, with the exception of a single August bird from
Amoy [now Xiamen, Fujian province, China]. Those specimens identified
as ‘Swinhoe’s dealbatus’ are listed in
Appendix 1, and their locations are shown in Fig. 1.
Smithsonian Institution (USNM), Division of Birds, Washington
DC, U.S.A.
The USNM collection holds 46 specimens of Kentish Plover collected
in East and South-East Asia, including 41 from China (including Hong
Kong), three from Malaysia and two from Thailand. Deignan (1941) examined
these specimens and commented that this collection held several pale
specimens including a series from Amoy collected in June and July,
plus others from northern China, Thailand and Malaysia. B. Schmidt
of the Smithsonian Institution, Division of Birds, photographed those
specimens to which Deignan referred, enabling us to review the identifications.
Based upon these photographs, the identification of nine specimens
(five from southern China, one from Thailand and three from Malaysia)
has been established as ‘Swinhoe’s dealbatus’
and these are listed in Appendix 1. The remainder are undoubtedly
typical ‘eastern’ Kentish Plovers.
National Museum of Natural History (RMNH), Leiden, the Netherlands
H. van der Grouw of the RMNH, Leiden, located four Kentish Plover
specimens collected by Swinhoe prior to 1870 in this collection, and
photographed these on our behalf. Of these, two collected at Amoy
in April 1861 belong with ‘Swinhoe’s dealbatus’
and are included in Appendix 1. The remaining two specimens are ‘eastern’
Kentish Plover.
Other collections
PDR examined the collections held at the Thai Natural History Museum,
and the Thailand Institute of Scientific and Technological Research,
but was unable to locate any specimens amongst the Kentish and Malaysian
Plovers. In addition, the following collections responded to our request
for information, but appear not to hold any relevant Swinhoe specimens:
American Museum of Natural History, New York, U.S.A.; Museum für
Naturkunde, Berlin, Germany; Manchester Museum, England; and Academy
of Natural Sciences, Philadelphia, U.S.A. |
WHAT
IS ‘SWINHOE’S dealbatus’?
The conflicting appearance of these plovers from within the type locality,
together with what appeared to be temporal separation of pale and
dark birds, suggested that the bird hitherto recognised as Charadrius
alexandrinus dealbatus could actually comprise two taxa. To establish
whether the paler birds really were ‘Swinhoe’s dealbatus’,
reference was made to Swinhoe’s original source material, plus
his published works, and examination of the specimen designated as
the type of dealbatus.
Swinhoe clearly recognised that two forms of Kentish Plover were occurring
along the coast of southern China. Prior to formally describing these
pale-backed plovers, Swinhoe (1863) commented that,
"the birds that stay to breed along the coasts
and islands of South China and Formosa can at once be recognised
by their flesh-coloured legs, which in the arrivals from the north
are leaden. Our southern birds are, moreover, larger, very pale,
in some cases almost white, and never, to my knowledge, attain aught
but an indication of the bright rufous and black that adorn the
head of the northern form."
Shortly thereafter, Swinhoe (1870) published a short paper in Ibis
entitled ‘On the Plovers of the genus Ægialites
found in China’ in which he formally recognised these paler
plovers as distinct from ‘eastern’ Kentish Plover [then
Aegialites cantianus], and which he named Aegialites
dealbatus. Swinhoe (1870) also included the following description
of dealbatus which supplemented the details which previously
appeared in Swinhoe (1863) with the following description:
"Bill black, with an ochraceous-yellow spot at
base of lower mandible. Legs light yellowish-brown or flesh colour.
In other respects like a washed out Æg. cantianus... The male
in summer plumage always has the latero-pectoral patch more or less
black, as also the band over the white forehead. The loral streak
sometimes shows in pale rufescentbrown, sometimes in black spots,
and is rarely entirely wanting. The crown has generally some rufescence;
and a rufescent tinge often washes over the back... The female in
July has a slight rufescence on the head, and a rufescent brown
breast-patch. She seldom acquires any of the dark markings of the
male."
At the time, Swinhoe would have been extremely familiar with Kentish
Plover, which he described in the 1870 paper as ‘coming down
the Chinese coast in winter in great numbers’, a statement that
still holds true today. Swinhoe’s conclusion was that dealbatus
closely resembled ‘eastern’ Kentish Plover and he appears
to have been readily able to distinguish the two taxa. Despite this,
he noted that ‘the legs and the bill afford the only reliable
characters for discrimination’, but then commented that ‘in
some specimens of true Æg. cantianus I notice a paleness
at the base of the lower mandible, and also in some a paleness of
the tarse [sic], both of which by a little intensifying would produce
the results characterizing our species’.
Swinhoe’s ability to distinguish between these two taxa did
not extend to his contemporaries. When Swinhoe’s specimens were
distributed into various collections, new labels were added that,
in some cases, clouded the clarity which Swinhoe provided. For example,
Seebohm correctly relabelled 12 of ‘Swinhoe’s dealbatus’
specimens (as Charadrius cantianus dealbatus), but also misidentified
five ‘eastern’ Kentish Plovers, which he also labelled
dealbatus. Similarly, Hume correctly relabelled two of ‘Swinhoe’s
dealbatus’ specimens, but mislabelled an ‘eastern’
Kentish Plover as dealbatus. |
SELECTION
OF A LECTOTYPE AND IDENTIFICATION OF THE TYPE SERIES
Little more appears to have been published until Sharpe (1896a) provided
a detailed description of the bird he considered to be Charadrius
cantianus dealbatus. In this, he described the upperparts of
the male as
‘general colour above pale earthy brown, with
faint remains of paler margins to feathers’
while the crown was described as
‘ash-brown, washed with light tawny-rufous,
especially distinct towards the nape’
He considered the
‘forehead and a distinct eyebrow white, with
a broad black band separating the white of the forehead from the
brown of the crown; eyelid and loral streak black; feathers below
the eye and sides of face white, with a black patch on the hinder
ear-coverts; cheeks and under surface of body pure white, with a
patch of black on each side of the chest’
Sharpe also described the female as appearing
‘similar to the male, but with less rufous on
the head, this being represented by a tinge over the eye and round
the nape, the black band on the fore part of the crown absent, the
black patch on each side of the chest represented by a brown patch
with a rufous tinge.’
The above description, which mentions these birds showing a black
loral streak, suggests that Sharpe may have included some male ‘eastern’
Kentish Plover, perhaps incorrectly labelled as dealbatus, within
the series he was examining. Nevertheless, this was followed by a
discussion in which Sharpe stated that,
"I do not see any advantage in upholding Ægialites
dealbatus, which is supposed to differ by its paler legs. While
admitting that most of the Chinese birds differ in this way, there
are many birds, also from China, which have dark legs like the ordinary
typical form, while it is equally certain that birds from other
localities also have pale legs. In one instance I have seen a bird
that had one dark leg and one pale one, so that apparently the skin
of the leg dries in different colours."
As Swinhoe did not select a particular specimen to represent the type
of Aegialites dealbatus, there is no specific type locality
as such. Consequently, the type locality becomes the entire range
of the species as defined by Swinhoe, i.e. ‘the South coast
of China, including Formosa and Hainan’. Sharpe (1896b), with
access to these same specimens (including the incorrectly labelled
specimens), selected a specimen (BMNH 1896.7.1.559), to represent
the type of Aegialites dealbatus, which is retained in NHM,
and carries three labels. The first is in the handwriting of Robert
Swinhoe, who collected the bird at Amoy in May 1861, and bears the
name Hiaticula nivosa, Cass., but which has been subsequently
changed, apparently in Swinhoe’s hand, to Hiaticula dealbata
and noted as a female (although plumage characters suggest it to be
an abraded male). This specimen later entered the collection of Henry
Seebohm, who added a second label using the name Charadrius cantianus
dealbatus. The third label, added by NHM when Seebohm’s
specimens came to the collection shows this be the lectotype of Aegialitis
dealbatus.
In selecting the lectotype from Swinhoe’s specimens, Sharpe
(1896a, b) neglected to provide a description of this specimen. In
these circumstances, Warren (1966) stated that the ‘listing
of a syntype as “the Type”, as was often done in the Catalogue
of Birds (BM 1874–1898), does not constitute its designation
as lectotype; nor of course does its listing in the present work’.
Thus, Warren argued that 1896.7.1.559 cannot be the lectotype of dealbatus
as it is not accompanied by a description. To date, therefore, a lectotype
of dealbatus as defined by Warren (1966) has not been designated.
In order to fix the identity of Aegialites [Charadrius] dealbatus,
a lectotype must be selected from the material which Swinhoe had available
when he described dealbatus. The selection of a lectotype
is necessary because dealbatus is presently represented by
a composite series comprising two distinct taxa. There are 15 specimens
of ‘Swinhoe’s dealbatus’ in NHM, Tring,
together with 21 ‘eastern’ Kentish Plovers, all collected
by Swinhoe from the coast of south China and Hainan on dates prior
to 1870 (i.e. the material that Swinhoe would have had available to
him when describing dealbatus). From these specimens, we
hereby designate BMNH 1896.7.1.559 as the lectotype of Aegialites
[Charadrius] dealbatus (Plate 1). Support for this decision is
provided by reference to the characters which Swinhoe (1863, 1870)
used to describe Aegialites dealbatus, and which apply to
this specimen. |
Plate 1.
Lectotype of Aegialites [Charadrius (alexandrinus)] dealbatus
held in NHM, Tring, (BMNH 96.7.1.559), collected by Robert Swinhoe
at Amoy [Xiamen, Fujian province, China] in May 1861. In all plumages,
this taxon is characterised by its pale legs and pale base to the
lower
mandible, larger, heavier bill structure, significantly paler upperparts
and longer and more conspicuous wing bar, particularly across the
inner primaries, than Kentish Plover. (Peter Kennerley © NHM,
Tring) |
The
14 remaining specimens of ‘Swinhoe’s dealbatus’
together with the lectotype, plus a further 21 ‘eastern’
Kentish Plovers collected by Swinhoe prior to 1870 from the type locality
and held in NHM, Tring, form part of the composite series and become,
by default, paralectotypes of Aegialites dealbatus. In addition,
all additional Swinhoe specimens collected prior to 1870, including
ten held in USNM, Washington, and the four in the RMNH, Leiden, also
become paralectotypes. Appendix 2 provides details of all known paralectotypes
of Aegialites dealbatus and identifies those specimens that
are correctly assigned to ‘Swinhoe’s dealbatus’
and those which are ‘eastern’ Kentish Plovers, incorrectly
placed within this taxon. This list is not exhaustive, and others
may come to light in the future. |
DESCRIPTION
OF THE LECTOTYPE OF AEGIALITES [CHARADRIUS] DEALBATUS
The lectotype (BMNH 1896.7.1.559) was collected at Amoy [Xiamen, Fujian
province, China] in May 1861 by Robert Swinhoe, and is housed in the
NHM, Tring. Although the data on the label states that this specimen
was sexed as a female, plumage characters strongly suggest this bird
to be a male.
Slightly larger than Kentish Plover. Bill black with
a pale base to the lower mandible, appearing slightly longer than
that of Kentish Plover with prominent ‘culmenary bulge’
at the tip. Tarsus and tibia rich
tan-brown on dried specimen. Toes dark brown. Claws
black. Forehead and supercilium
white, lores white, sparsely flecked with small,
pale brown spotting. Ear-coverts lightly washed pale
greyish-brown. Fore-crown marked with a broad, dark
brown band. Crown pale sandy-brown, becoming warm
orange on the lower edge of the rear crown. Collar
white. Mantle and scapulars pale
sandy brown with thin, dark brown shaft streaks and slightly paler,
narrow tips. Greater coverts pale greyish-brown,
slightly darker than the median coverts and broadly tipped white.
Median coverts pale greyish-brown lacking broad white
tips. Lesser coverts dark brown, becoming darkest towards the carpal
bend. Primary coverts dark brown, narrowly tipped
white, and appearing as the darkest part of the closed wing. Alula
dark brown at the tip, paler brown towards the base. Inner
primaries (P1–P6) mid brown with white panel on the
basal half of the outer web, becoming darker towards the tip, although
each narrowly tipped creamy-white. Outer primaries (P7–P10)
dark brown and unmarked but with creamy-white shafts. Secondaries
mid brown as the inner primaries, with narrow white tips to the outermost,
these tips becoming progressively broader and whiter towards the body,
and extending along the outer web on the inner secondaries. Tertials
pale sandy-brown and heavily worn. Tail with central
two pairs of rectrices (T1–T2) dark brown, becoming darker,
colder brown towards the tip; this being the darkest region of upperparts.
Feather shafts blackish. Rectrix T3 dull creamy-white at the base,
becoming pale grey-brown towards the tip, this being more extensive
on the outer web than the inner. The outer web also showed a narrow
white fringe extending along the feather to the tip but there was
no similar pale fringe along the inner web. Fourth outer pair (T4)
creamy-white apart from a faint brown, lozenge-shaped spot near the
tip of the inner web. Outer two pairs of rectrices (T5–T6) entirely
creamywhite and unmarked. Entire underparts from
the chin to the undertail-coverts
white with a faint cream tinge, and unmarked. Sides of the
breast marked by small, dark brown lateral breast patches,
extending from the carpal bend to the sides of the breast but not
reaching onto the breast. Wing 113 mm; tail 47 mm;
tarsus 28.6 mm; bill length to feathering
18.5 mm.
Additional details, including descriptions of other known plumages
and features which define the distinctive character of ‘Swinhoe’s
dealbatus’, are detailed in Diagnosis (below). |
CONFUSION
BETWEEN SWINHOE'S DEALBATUS AND EASTERN KENTISH PLOVER
The status quo was maintained until Hartert and Jackson (1915) undertook
a review of the plovers comprising the genera Charadrius,
Aegialites and Eudromias, which they combined
into the single genus Charadrius. With Swinhoe’s
specimens of dealbatus available to them at NHM, they realised
that Sharpe’s (1896a) decision to treat Kentish Plover as
a monotypic species was unsound, but they appear unaware that a
‘type’ specimen of dealbatus had been selected
by Sharpe (1896b). Even with this series available to them, they
apparently failed to appreciate fully the differences between ‘Swinhoe’s
dealbatus’ and ‘eastern’ Kentish Plovers.
Furthermore, they appear not to have referred to the original descriptions
provided by Swinhoe (1863, 1870), as the issue of leg colour was
still problematic. For example, Hartert and Jackson commented that
birds obtained by Alan Owston’s collectors in Japan, which
they believed to be dealbatus, were described on the specimen
labels as showing black legs. They did, however, recognise that
the larger, stouter bill of ‘Swinhoe’s dealbatus’
set it aside from ‘eastern’ Kentish Plover, and they
considered this character to be sufficiently distinctive to reinstate
dealbatus as a race of Kentish Plover, which they named
Charadrius alexandrinus dealbatus. It is surprising, however,
that they did not acknowledge the distinctive appearance of dealbatus,
in particular the paler upperparts and lack of a dark loral line,
as in the same article they used these same features in the diagnosis
of C. a. nivosus as a race of Kentish Plover. This treatment
of dealbatus, as being larger-billed but otherwise very
similar to the nominate race of Kentish Plover, was followed by
all subsequent authorities throughout the twentieth century. At
this point, Hartert and Jackson also mistakenly included Taiwan,
the Ryukyu Islands and southern Japan within the range of dealbatus
when they wrote:
"This
form is resident in south China, Hainan, Formosa, and the Riukiu
(Loo-Choo) Islands, and Japan at least as far north as Yokohama,
where in winter C. a. alexandrinus also occurs as well. In the
British Museum, a specimen from Amherst in Burma; also a female
from Zaidam in Central Asia belongs to this race."
The treatment of dealbatus by Hartert and Jackson (1915),
which correctly described it as being larger-billed, but erroneously
concluded it to be otherwise very similar to the nominate race of
Kentish Plover, has become widely accepted. Furthermore, the inclusion
within its distribution of extensive regions of eastern Asia from
which it is in fact unknown (there are no specimens or substantiated
reports from any of these countries or regions mentioned above) has
given rise to the misconception that dealbatus is the widely
occurring form of Kentish Plover in eastern Asia. ‘Swinhoe’s
dealbatus’ then vanished from the public perception,
and subsequent taxonomists and authors throughout the twentieth century
overlooked its distinctive appearance, assuming all ‘eastern’
Kentish Plovers to be dealbatus. |
COMMENTS
ON ADDITIONAL SPECIMENS OF "SWINHOE'S DEALBATUS" IN NHM
Following Hartert and Jackson’s (1915) treatment of Kentish
Plover, it appears that little attention was paid to the separation
of ‘Swinhoe’s dealbatus’ and ‘eastern’
Kentish Plover, as there was little or no perceived difference between
the two taxa. So when further specimens of what are clearly ‘Swinhoe’s
dealbatus’ were registered at NHM, including eight
specimens from the Delacour and Jabouille Collection, taken at the
former French colony of Kouang-Tcheou-Wan [Zhanjiang, Guangxi province,
China] in 1932, and four collected during the Franco-British second
expedition to Indo- China by Delacour and Lowe, mostly from Thuan
An, near Hué, Vietnam, in September (2), November 1925 (1),
and April 1926 (1), all were correctly labelled as dealbatus.
However, with the four from Thuan An, but not distinguished from them,
are nine ‘eastern’ Kentish Plovers, also labelled dealbatus
and collected in November 1925. Consequently, the two taxa were included
together in museum trays without any attempt to separate the pale-mantled
and dark-mantled birds, resulting in dealbatus becoming a
composite comprising two taxa. |
WHAT
ARE "EASTERN" KENTISH PLOVERS?
If the name dealbatus can be applied only to those birds
matching the description given by Swinhoe, then the darker-mantled,
dark-legged Kentish Plovers that occur in abundance along the coasts
of East and South-East Asia must be something else. In fact, these
latter birds are not readily separable from the nominate race of
Kentish Plover, although some individuals show a tendency towards
a larger and heavier bill, which can approach that of ‘Swinhoe’s
dealbatus’.
When reviewing
the extensive material available from East Asia in the US National
Museum, Deignan (1941) remarked that he
‘arrived at conclusions rather at variance with
those of the most recent revisers’
He commented that
‘A good series from Amoy (June, July) are decidedly
paler than birds from Europe, have a longer and more massive bill,
and in every case have the upperparts suffused with rufous. Swinhoe’s
description of dealbatus as a “washed out”, rufescent
tinged alexandrinus fits these specimens perfectly’
He goes on to note that
‘Another series of badly worn birds from Chihli
(July) are probably dealbatus. In addition, I have seen examples
of this race from Hong Kong (October, November), and Hainan (March)’
Outside China, he commented that
‘Two birds from Thailand (November, March) and
two from Malaya (December), all in winter dress, are so remarkably
pale above that they stand out from all other Old World specimens
I have seen and can be fairly compared with nivosus and tenuirostris
of the New World’
It seems
clear that what Deignan had discovered was a series of specimens that
matched ‘Swinhoe’s dealbatus’. Deignan
then compared these paler specimens with a series of birds from breeding
locations in Japan, which he described as having ‘the upperparts
without the least rufescent wash and quite as dark as European specimens,
but differ from the latter in having the bill as long and as massive
as dealbatus’, although this statement is not quantified
or supported by measurements. Deignan proposed the name Charadrius
alexandrinus nihonensis for the Kentish Plovers featuring this
larger, heavier bill structure, with an adult male selected as the
type specimen (USNM 95938), taken at Aomori, Hondo [Honshu], on 23
April 1876 by Captain T. W. Blakiston. We have examined photographs
of the type specimen of nihonensis (Plate 2) and can confirm
that it is a dark-mantled, darklegged male Kentish Plover in breeding
plumage, and closely resembles the nominate form, other than its marginally
larger bill. |
Plate
2. Type specimen of Charadrius alexandrinus nihonensis
described
by Deignan (1941), and held in US National Museum, Washington
DC, USA (USNM 95938), collected by Captain T. W. Blakiston at
Aomori, Hondo [Honshu], Japan, on 23 April 1876. Birds assigned
to
this form closely resemble the nominate race of Kentish Plover but
are
distinguished by a slightly heavier bill structure, marginally darker
upperparts and a richer cinnamon-orange crown. (Brian Schmidt
© USNM, Washington DC) |
Deignan
also noted, however, that birds taken in China to the north of the
range of dealbatus are ‘dark backed and have a bill
somewhat smaller than nihonensis but nevertheless larger
than alexandrinus’. While recognising there is substantial
variation in bill size in Kentish Plover, and also that young birds
tend to have smaller bills than their parents, Deignan concluded that
‘even the shortest billed examples from the Pacific coasts of
Asia have the bill rather more massive than European birds of the
corresponding age and sex—a difference that must be seen to
be appreciated—and are thus better called nihonensis’.
Comments by
Nechaev (1988), who examined Kentish Plover specimens collected
during the breeding season from all parts of the territory of the
former Soviet Union (FSU), support Deignan’s findings. Nechaev
concluded that nominate alexandrinus occupied the breeding
range of Kentish Plover throughout the FSU, with the exception of
Sakhalin, and Kunashir and Moneron in the southern Kuril Islands.
Here, he established that breeding birds differed from nominate
alexandrinus in their larger bill structure, and, to a
lesser extent, longer wing length. He considered the Sakhalin and
Kuril birds to be otherwise identical in appearance to the nominate
form and concluded they belonged to the race dealbatus. In fact,
these slightly larger birds fit the description of C. a. nihonensis,
which was (and mistakenly still is) treated as a synonym of dealbatus.
Nechaev also recognized that the Kentish Plovers breeding in the
southeast Russian region of Primorsky, bordering the Sea of Japan,
had a bill structure that was, on average, slightly smaller than
that of the birds breeding on Sakhalin and Kunashir, but marginally
larger than that of nominate alexandrinus from elsewhere
in the FSU. This suggests that an imperceptible change from nihonensis
to alexandrinus occurs in this region but there is no convenient
geographic division which separates the two races.
Deignan (1941)
went largely unnoticed, and was certainly overlooked by those familiar
with Kentish Plover in Asia, who continued to refer to ‘eastern’
Kentish Plovers as dealbatus. All recent accounts of Kentish
Plover have incorrectly treated nihonensis as a junior
synonym of dealbatus. Other than bill structure, there
are additional minor differences that set nihonensis apart
from nominate alexandrinus, although it is not known to
what extent the intermediate populations on the adjacent mainland
also exhibit these characters. It is marginally darker on the upperparts
and, most conspicuously, the males display a dark, rich cinnamon-orange
crown that nominate birds rarely approach. In addition, ‘eastern’
Kentish Plover shows a greater tendency towards displaying a narrow
but complete breast-band across the upper breast, particularly in
females (and males in non-breeding plumage?), a feature rarely encountered
in nominate alexandrinus (Chandler and Shirihai 1995, Leader
2001).
Outside the
breeding season, it is uncertain which races of Kentish Plover occur
in South-East Asia. It seems probable that birds breeding over an
extensive region of northern Asia, and probably within the range
of nominate alexandrinus, may be occurring alongside larger-billed
birds resembling nihonensis from the east of the range.
In juvenile, first-winter and adult non-breeding plumages, however,
separation of the races of Kentish Plover using bill structure alone
has proved impossible. Although a small minority of Kentish Plovers
wintering in South- East Asia, including birds observed in the field
and specimens from this region examined in museum collections, do
appear to differ from Kentish Plovers occurring to the west, many
are identical and only an insignificant minority are slightly larger-billed;
and there is no way to establish their place of origin. |
ETYMOLOGY
The species was
named Aegialites dealbatus by Swinhoe. Species previously
forming the genus Aegialites, which is no longer recognised,
are now included within Charadrius. The genus name Charadrius
is believed to have its origin in the ancient Greek word kharadrios
meaning ‘a nocturnal waterbird’, while dealbatus
is derived from the Latin verb dealbare, meaning ‘to whiten’.
This was presumably the term which Swinhoe thought best described
the pallid appearance of this plover when compared with the Kentish
Plovers with which he was familiar. |
DIAGNOSIS
OF "SWINHOE'S DEALBATUS"
Size
and structure
Similar in size to migratory forms of Kentish Plover occurring in
Asia, but slightly and consistently larger and heavier-bodied. In
addition, the head appears proportionately larger than that of Kentish
Plover and this, together with the more substantial bill structure,
gives the head a robust and heavier appearance. In this respect,
the bill structure and head shape of dealbatus appear closer
to that of the slightly larger Lesser Sand Plover C. mongolus
than to Kentish Plover. In addition, the tibia appears to be consistently
longer than that of Kentish Plover, but it has not been possible
to substantiate this by measurement from specimens.
To investigate
possible structural differences, a series of measurements was taken
from specimens of ‘Swinhoe’s dealbatus’,
Asian C. a. alexandrinus, C. a. seebohmi and C.
peronii (see legend in Table 1 for details).
Although there
is extensive overlap with Kentish Plover on all measurements, these
demonstrate that ‘Swinhoe’s dealbatus’
is, on average, slightly longer-winged and longerlegged, and also
that it consistently shows a slightly larger, heavier bill than
Kentish Plover (Table 1). These apparently minor structural differences
can be surprisingly apparent in the field where, in particular,
the bill structure of dealbatus appears more massive and
blunt-tipped, and more parallel-edged and ‘tubular’
in shape than that of Kentish Plover. In dealbatus, the
ratio of ‘nail’ length to exposed culmen length has
a mean value of 0.49, compared with mean values of 0.47 in ‘eastern’
Kentish Plover, 0.43 in C. a. seebohmi and 0.51 in C.
peronii (Table 1). Although these mean values are quite similar,
when viewed on birds in the field, they translate to the short,
stubby appearance to the bill of Malaysian Plover and to the short
and relatively slender bill of C. a. seebohmi. Even between
‘Swinhoe’s dealbatus’ and ‘eastern’
Kentish Plover the visible difference can be striking. This feature
is particularly noticeable when the bird turns slightly away from
the observer, fore-shortening the bill length. |
Table
1. Comparison of wing and tarsus length, and bill structure
taken from specimens at NHM, Tring, of ‘Swinhoe’s dealbatus’,
Kentish Plover C. a. alexandrinus from locations in East
and South-East Asia, Kentish Plover C. a. seebohmi from
Sri Lanka and Malaysian Plover C. peronii from locations
throughout South-East Asia. Measurements of sexes are combined.
Wing length (maximum chord) was measured to nearest mm, with measurements
of tarsus and bill structure taken to nearest 0.1 mm. The term ‘nail’
here refers to the dertrum, this being the ‘culmenary bulge’
or distal bill swelling found on the upper mandible. Nail length
is defined as the distance from the bill tip to the point where
the ‘culmenary bulge’ meets the culmen, and nail depth
is the maximum bill depth measured over the ‘culmenary bulge’.
Figures in parentheses represent limits, standard deviation and
sample size.
|
"Swinhoe's
dealbatus" |
C.
a. alexandrinus |
C.
a. seebohmi |
C.
peronii |
Wing |
113.1
(105–121; 3.20; 32) |
111.7(104–117;
3.05; 101) |
101.4(96–106;
3.13; 10) |
98.8(94–102;
2.28; 41) |
Tarsus |
28.2(25.6–29.7;
0.87; 32) |
27.2(24.6–29.4;
1.30; 97) |
26.2(24.9–26.8;
0.74; 10) |
28.8(26.0–31.0;
1.29; 40) |
Bill
length (to skull) |
23.7(21.1–25.7;
1.07; 32) |
22.3(19.5–24.4;
1.02; 101) |
19.5(18.8–20.7;
0.60; 9) |
20.8(19.4–22.8;
0.81; 40) |
Bill
length (to feathering) |
17.8(16.4–19.5;
0.87; 31) |
16.5(14.1–18.7;
1.16; 100) |
15.0(14.1–15.9;
0.76; 9) |
15.0(13.7–16.8;
0.55; 40) |
"Nail"
length |
8.8(8.1–10.2;
0.50; 32) |
8.0(6.2–9.5;
2.14; 94) |
6.5(5.7–6.7;
0.34; 9) |
7.4(6.5–8.0;
0.31; 40) |
Bill
depth at "nail" |
3.8(3.4–4.4;
0.24; 30)
m |
3.6(3.0–4.0;
0.57; 91) |
3.1(2.8–3.4;
0.21; 9) |
3.8(3.4–4.1;
0.19; 38) |
Bill
width at feathering |
4.9(4.1–5.6;
0.39; 29)
m |
4.7(3.7–5.6;
0.34; 94) |
4.3(3.8–4.8;
0.31; 10) |
4.9(4.3–5.6;
0.28; 39) |
Mean
‘nail’ length/bill
length to feathering |
0.49 |
0.47 |
0.43 |
0.51 |
|
Plumage
All birds observed, and the specimens examined to date, have been
on dates ranging between late September and mid-July. Criteria used
to establish ages referred to below are those used to age and sex
similar Charadrius plovers, as described by Prater et al.
(1977). Body moult occurs from late December to early February, and
during this period birds appear transitional in appearance, between
presumed first-winter and first-summer breeding plumages described
below. A selection of images that illustrate a wider range of plumages
than appear here can be found in Bakewell and Kennerley (2007, 2008). |
Plate 3. Adult male Charadrius [alexandrinus]
dealbatus, breeding plumage (early February onwards), Tanjung
Tokong, Penang, Malaysia, 6 February 2007. (David Bakewell) |
Plate 6. Adult female Charadrius [alexandrinus]
dealbatus, breeding plumage (early February onwards), Tanjung
Tokong, Penang, Malaysia, 6 February 2007. (David Bakewell) |
Plate 4. Presumed first-winter male Charadrius
[alexandrinus] dealbatus (October to late December), Tanjung
Tokong, Penang, Malaysia, 24 November 2007. (David Bakewell) |
Plate 7. Presumed adult female Charadrius [alexandrinus]
dealbatus, non-breeding plumage (October to late December),
Tanjung Tokong, Penang, Malaysia, 21 November 2007. (David Bakewell) |
Plate 5. Presumed first-summer male Charadrius
[alexandrinus] dealbatus, breeding plumage (early February onwards),
Tanjung Tokong, Penang, Malaysia, 6 February 2007. (David Bakewell) |
Plate 8. Presumed juvenile Charadrius [alexandrinus]
dealbatus, Karon Beach, Phuket, Thailand, 15 November 2003. (Petteri
Lehikoinen) |
Wing
and tail pattern
Both sexes share a similar wing and tail pattern, which does not
appear to differ with age. Although ‘Swinhoe’s dealbatus’
shares with Kentish Plover a conspicuous white wing-bar extending
across the centre of the upperwing, the overall upperwing colour
and pattern differs substantially. The upperwing-coverts (except
the primary coverts) are much paler than those of Kentish Plover
and therefore provide a greater contrast with the dark alula, primary
coverts and outer primaries than Kentish shows. This pallid appearance
is further enhanced by the extension of white along the outer webs
of the inner primaries, which is longer than on Kentish, while on
the inner wing broad white tips to the greater coverts enhance the
wing-bar width towards the body, so that the wingbar appears both
broader and more conspicuous when compared to that of Kentish Plover.
Unlike Kentish
Plover, the outer greater coverts and the outer median coverts of
dealbatus, which are also tipped white, contrast against the sandy-brown
lesser coverts and slightly darker mid-brown, white-tipped inner
primary coverts to form a short, narrow bar which branches from
the greater coverts and curves towards the alula, but does not reach
the outer edge of the wing. In addition, fairly broad and conspicuous
white tips to the dark brown secondaries create a third white bar
in the wing, along the trailing edge of the wing in flight.
Also visible
in flight, the white in the tail appears more conspicuous than that
of Kentish Plover, with the outer three pairs of rectrices being
almost entirely white, and only the inner two pairs being dark brown
and lacking white.
At rest, differences
in the colour of the fringing to the lesser and median coverts on
the closed wing are apparent. On Kentish Plover these fringes are
buff-brown and show subdued contrast with the feather centres, while
on dealbatus they are whitish and show a distinct contrast, although
this becomes less apparent with time as a result of feather wear.
This difference can also be apparent on birds in flight, with the
paler lesser and median coverts of dealbatus contrasting with the
darker brown marginal coverts, and forming a noticeable dark bar
along the leading edge of the inner wing. In Kentish Plover, the
inner wing appears much darker and there is little or no trace of
the darker marginal covert-bar.
Adult
male breeding plumage (early February onwards). Plate 3
Pattern resembles male Kentish Plover, with white forehead and supercilium,
orange crown and dark lateral breast-patches. Unlike Kentish Plover,
the crown is purer, brighter orange, the loral region and ear-coverts
largely or entirely white—although some birds do show scattered
darker feathering or a dark smudge immediately in front of the eye,
this being most conspicuous when worn but occasionally visible on
birds in fresh plumage in February. Exceptionally, a male observed
by DNB (February in Singapore) showed a narrow, dark line extending
from the eye to the bill-base. The white forehead is broader and
more extensive than in Kentish Plover, so the dark eye is isolated
and surrounded by white feathering, resembling Snowy Plover, and
the supercilium is broader and longer, with white extending well
behind the eye. The blackish frontal bar across the fore-crown is
wider than in male Kentish, and the crown bright orange rather than
dull orange. The nape is white, forming a complete white collar
separating the orange crown from the mantle, whereas on Kentish
a narrow brown line extending down from the crown divides the white
collar. The entire upperparts, including the mantle, scapulars,
wing-coverts
and tertials, are uniform pale sandy-brown, and clearly paler than
the corresponding darker, wet-sand tone to the upperparts of Kentish
Plover. The darker primaries project slightly beyond the longest
tertial. A conspicuous blackish-brown patch on the side of the breast
in front of the carpal bend is narrower, smaller and shorter than
the equivalent patch on male Kentish Plover, resulting in the extent
of white between the breast-patches being consistently wider than
shown by Kentish Plover. Otherwise, the entire underparts from chin
to undertailcoverts are white.
Presumed
first-winter male non-breeding plumage (October to late December).
Plate 4
Resembles the adult male breeding plumage but the head pattern is
subdued, with the supercilium behind the eye lightly washed diffuse
grey, and light grey around and below the lower edge of the eye,
forming a dark ‘shadow’. In front of the eye, this appears
as a small grey spot, but otherwise the lores remain white. The
forehead is white, but the dark fore-crown bar is largely obscured
with whitish tips, and appears pale grey. The crown is pale sandybrown
like the mantle, but the sides to the crown and hind-crown are dull
orange-brown. The dark patches on the sides of the breast appear
slightly greyer and paler than those of the breeding male.
Presumed
first-summer male breeding plumage (early February onwards). Plate
5
Similar to adult male in breeding plumage and some may not be separable
(e.g. see leg-flagged male in Bakewell and Kennerley 2008, plate
11, which was aged as a firstwinter when trapped in October 2007).
Other birds assumed to be this age differ from the adult male in
showing a narrow and broken dark frontal bar on the fore-crown,
which in some individuals can be almost absent. The crown is duller
than bright orange of the adult, particular towards the centre where
it is usually similar in colour to the mantle, but becoming brighter
at the sides and across the lower rear-crown. The lateral breast-patches
are usually smaller and less obvious than those of the adult male,
varying in colour between sandy-brown (as the mantle) and dull blackish-brown,
but at this age often two age classes of feathers are present, creating
a mottled appearance to these patches. The replaced mantle and scapulars
are slightly warmer and darker than in the adult male, and contrast
with the retained, worn and paler juvenile wing-coverts.
Adult
female breeding plumage (early February onwards). Plate 6
The overall appearance of the upperparts is consistently paler than
in Kentish Plover, while the crown and breastpatches are sandy-brown
with a fairly bright rufous or orange wash, and recall female Malaysian
Plover. It usually lacks the entirely white-faced appearance of
the male, although the forehead and supercilium are white. However,
the lores and ear-coverts are pale sandy-brown with a light rufous
or orange wash, forming a distinct eyestripe. The crown is sandy-brown
with a rufous or orange wash, hooking down behind the supercilium
to join the eye-stripe behind eye. The nape is white, forming a
complete collar separating the crown from the pale sandybrown mantle.
The entire upperparts are pale sandybrown as in the male, although
indistinct dull chestnutbrown fringes may be apparent on the scapulars,
giving them a slightly warmer and richer appearance compared with
the mantle. The lateral breast-patches are pale sandybrown with
a rufous or orange wash, similar to the crown colour or slightly
duller and browner and, as in the male, not as deep or extensive
as on female Kentish Plover. The entire underparts from chin to
undertail-coverts are white, and the extent of white between the
two breast-patches is consistently wider than shown by female Kentish
Plover.
Presumed
adult female non-breeding plumage (October to late December). Plate
7
Differs from the adult female breeding plumage by its lack of reddish-brown
on the crown and breast-patches. The extent of the loral line is
variable; on some birds this forms an indistinct sandy-brown line
reaching to the bill, while on others the loral region remains white
or shows an indistinct sandy-brown spot immediately in front of
the eye. The dark coloration on the ear-coverts is much less extensive
than shown by Kentish Plover, not extending onto the lower ear-coverts.
The upperparts including the crown and mantle are uniform pale sandy-brown.
However, scapulars usually contrast with the paler-fringed wing-coverts
when visible.
Juvenile.
Plate 8
Closely resembles the adult female in non-breeding plumage but differs
in appearance by the presence of narrow but conspicuous pale fringes
to the mantle and scapulars, giving the upperparts a slightly scaled
appearance.
Bare
parts
Legs: variable in colour. Adult males vary from
dull midgrey with a slight pinkish tinge to pale flesh, the legs
appearing darker on freshly moulted males in February and March.
The legs of adult females are distinctly paler than those of most
males, with grey tones almost or entirely absent, and replaced with
dull pink or flesh tone, sometimes with a hint of ochre. Importantly,
however, the legs are invariably and conspicuously paler than the
bill. Only the most extreme Kentish Plover will occasionally show
leg colour approaching that of dealbatus, and no dealbatus has been
noted with legs approaching the dark grey of Kentish Plover. Bill:
in both sexes black, apart from the base of the lower mandible which
is yellowishbrown, similar in pattern and colour of the lower mandible
of Malaysian Plover. Eye: black, and appearing
proportionately larger than the eye of Kentish Plover.
Moult
and wear
The moult strategy has not been studied in detail, but is believed
to be similar to that of Kentish Plover. All birds appear to undertake
a pre-breeding moult between December and January, during which
the distinctive breeding plumage is acquired, although in second
calendar year birds the brighter tones of the breeding plumage may
be subdued. As no male specimens (collected between May and July)
show the distinctive orange cap seen in the wintering areas, it
is assumed that this abrades fairly quickly to reveal the pale brown
feather-bases, possibly as early as May, when some small, dark feathering
may appear on the lores, very occasionally forming a solid loral
line.
Following the
breeding season, it is assumed that a complete moult takes place
although the timing for this has not been established. What is currently
uncertain is why some birds wintering in Singapore and Malaysia
adopt a pale, nondescript plumage outside the breeding season, while
birds wintering in Vietnam retain the breeding plumage throughout
the winter months. It now seems likely that at least some of these
early-arriving birds in nondescript plumage are first-winter birds,
which moult into a ‘first-summer’ plumage the following
spring. This would accord with other Asian Charadrius plovers,
which are either resident in the tropical regions or short-distance
migrants which retain the same ‘breeding’ plumage throughout
the year, including Malaysian Plover, Javan Plover, Kentish Plover
C. a. seebohmi and Little Ringed Plover C. dubius
of the south Asian form jerdoni. Further observations should
provide answers to these questions. |
COMPARISON
WITH SIMILAR TAXA
Kentish
Plover
Migratory races of Kentish Plover are similar in size to ‘Swinhoe’s
dealbatus’, but invariably show dark lores and dark
feathering around and behind the eye. In all plumages, the upperparts
of both sexes of Kentish Plover are dull brown and appear considerably
darker and browner than dealbatus. Both sexes of Kentish Plover
also show larger and more extensive dark patches at the sides of
the breast, appearing wider and usually extending well forward of
the carpal bend, on some individuals even meeting across the centre
of the breast (Chandler and Shirihai 1995, Leader 2001), particularly
in ‘eastern’ Kentish Plovers. Another significant differentiating
character, particularly useful on birds in first-winter plumage,
is the extent of dark coloration on the lower earcoverts below and
behind the eye, which is always greater in Kentish Plover. Male
Kentish Plovers in breeding plumage display a dark frontal bar on
the fore-crown but this is usually narrower than that shown by ‘Swinhoe’s
dealbatus’, and the orange crown is slightly duller,
more subdued and shows a distinct cinnamon tone.
The resident
race C. a. seebohmi occurring in Sri Lanka and southern
India is a distinctive taxon that is significantly smaller than
the northern migratory form of Kentish Plover, overlapping in size
with Javan and Malaysian Plovers. Prior to the pre-breeding moult,
males can show restricted black feathering on the lores, with most
birds retaining a small patch of dark feathering immediately in
front of the eye or a narrow, dark line across the lores, flecked
with white feathering. Following the pre-breeding moult, in late
February, all males from a sample of over 80 observed in Sri Lanka
showed a narrow but solid dark line across the loral region. Compared
with other races of Kentish Plover, the head pattern of freshly
moulted male seebohmi is dull, subdued, poorly marked and without
the warm orange and cinnamon tones to the crown, resulting in an
appearance that is like a washed-out version of the northern, migratory
races. Female seebohmi are similar in size to the males,
but closely resemble female Kentish Plovers of the nominate form,
and so are darker than ‘Swinhoe’s dealbatus’.
Javan
Plover
The appearance of Javan Plover is poorly documented, but observations
of breeding birds at the Muara Angke reserve, on the western outskirts
of Jakarta, Java, have established that their appearance is quite
different to that of ‘Swinhoe’s dealbatus’.
In size, it is relatively small and compact, and comparable in size
to C. a. seebohmi. The upperparts vary from dark brown
to a paler dull sandybrown, similar in colour to ‘eastern’
Kentish Plover, while males show a warm rufescent-brown wash to
the lower crown and rear of the supercilium, which extends back
over the ear-coverts where it drops slightly. Importantly, the lores
are entirely dark, the patches at the sides of the breast are rufescent-brown,
not black, and the legs are dull greenish-grey.
Malaysian
Plover
Malaysian Plover is a relatively small Charadrius plover that overlaps
in size with C. a. seebohmi and Javan Plover, but is significantly
smaller than ‘Swinhoe’s dealbatus’ and
the migratory races of Kentish Plover (Table 1). Bill coloration
and structure and upperwing pattern are strikingly similar to ‘Swinhoe’s
dealbatus’. It also shares the dark fore-crown bar
and bright orange crown, and some males show entirely white and
unmarked lores, and appear uncannily like some male ‘Swinhoe’s
dealbatus’. In most, however, a narrow line of dark
feathering extends from the eye to the bill-base. Male Malaysian
Plover always shows a dark collar across the upper mantle, below
the white collar, that joins with the dark patches at the sides
of the breast. These patches are usually longer and deeper on Malaysian
Plover, and on some individuals can almost meet across the breast.
In addition, although the upperpart feathering of both sexes of
Malaysian Plover is paler than shown by dealbatus and Kentish Plover,
the feathers on the mantle and scapulars show a broad, pale fringe
with a darker centre and a conspicuous dark shaft-streak, so the
upperparts lack the relatively uniform appearance of dealbatus.
Females more closely resemble female dealbatus, but the smaller
size and pattern to the mantle and scapulars remain constant differences.
There is a difference in the crown coloration between female Malaysian
Plover and female ‘Swinhoe’s dealbatus’.
Typically, female Malaysian shows orange on the fore, rear and sides
of the crown, while the centre is sandy-brown, while female ‘Swinhoe’s
dealbatus’ shows an even sandy or orange-brown colour. |
DISTRIBUTION
AND STATUS
Accounts from
the early decades of the twentieth century described ‘Swinhoe’s
dealbatus’ as a common breeding bird along the coast
of eastern China from Hainan north to Chihli [Hebei province]. But
this statement is confused by the belief at that time that all Kentish
Plovers breeding in coastal China were dealbatus, and not
just those along the south coast of China. For example, La Touche
(1931– 1934) described dealbatus as breeding ‘in
large numbers both on the coast of South-East China and on those
of Shantung [Shandong province] and Chihli [Hebei province]’.
He also describes finding nests at Swatow Bay [Shantou, Guangdong
province], and near Amoy (within the type locality of dealbatus)
but commented that he did not find any nests at Chinwangtao (Qinhuangdao,
Hebei province], although he had no doubt that it bred there, as
Wilder and Hubbard (1924) had described it as being abundant at
Peitaiho [Beidaihe, Hebei province] from early April to early September.
It is possible that La Touche’s description is an amalgamation
of northern and southern Chinese breeding birds, passage migrants
and wintering birds, based on the misconception of the appearance
of dealbatus and erroneous distribution comments by Hartert and
Jackson (1915), which included Taiwan, the Ryukyu Islands and southern
Japan north to Honshu within its range.
An earlier account
by Jones (1911) described Kentish Plover as ‘one of the commonest
breeding birds on the sandy wastes which border the Yellow Sea and
Gulf of Pechili [Gulf of Bohai] in so many parts of Shantung Promontory’.
Jones clearly assumed these northern breeders to be the same birds
which La Touche found breeding in Swatow, but he did not provide
a description of the birds he saw. Crucially, however, he did include
the comment that all Kentish Plovers here have black legs and none
was seen with pale legs. This strongly suggests that the birds Jones
was observing were ‘eastern’ Kentish Plovers rather
than ‘Swinhoe’s dealbatus’.
Outside the
breeding season Swinhoe considered dealbatus to be resident
in south China, although there is little evidence to support this.
In fact, the only report from south China to date outside the breeding
season relates to a female mentioned by Vaughan and Jones (1913),
who stated that one was obtained on mudflats at Macao [Macau, China]
on 30 January 1906, but provided no supporting details. However,
what is presumably this specimen is held in NHM (BMNH 1910.5.2.57)
and is clearly referable to ‘Swinhoe’s dealbatus’.
An unsubstantiated report was included in Seebohm (1893), who referred
to a female shot at Nagomagiri, Choda, Okinawa in the Ryukyu Islands,
Japan, on 9 February that showed ‘very pale legs’. Based
on this single character, he considered this bird belonged with the
Chinese race Charadrius cantianus dealbatus. But without
additional supporting evidence, there is nothing here to suggest that
this was anything other than a Kentish Plover with unusually pale
legs. In fact, a female Kentish Plover, also with pale legs that may
possibly resemble Seebohm’s bird, was photographed at Okinawa
on 20 March 2002, and can be seen at http://homepage2.nifty.com/stints/
ploveretc/kentishplv-awC.html
All specimens
of Kentish Plover that we have examined from northern China, Taiwan
and Japan, together with photographs of breeding birds taken in
these countries clearly establishes them as Kentish Plovers. While
it is possible, even likely, that ‘Swinhoe’s dealbatus’
bred to the north of Fujian province, we have not seen any evidence
to support this. Outside the breeding season, it is generally believed
that dealbatus ranges widely throughout coastal East and
South-East Asia. However, examination of specimens and photographs
from this region clearly shows that all are Kentish Plovers, with
the exception of those listed below and in Appendix 1.
With such apparent
confusion in the historical literature and museum specimens, it
is unwise to assume that any published distribution data relating
to the range of ‘Swinhoe’s dealbatus’
can be accurate unless supported by specimens or photographs. In
an attempt to establish the true distribution, all specimens of
Kentish Plover from eastern Asia held at NHM, Tring, and the Raffles
Collection, University of Singapore, were examined. Although most
were labelled dealbatus, the vast majority were found to
be ‘eastern’ Kentish Plovers. Only those supported by
specimens, photographs, field notes and sketches are included in
the country summaries below. Appendix 1 details the location of
all specimens which have been identified as ‘Swinhoe’s
dealbatus’, and these are shown in Figure 1.
In an attempt to gather additional distributional data, Bakewell and
Kennerley (2007) published a photo-essay on the Surfbirds website
(http://www.surfbirds.com/
Features/plovers1108/malayplovers.html). In addition to bringing
these birds to the attention of a larger audience, this article included
a review and comparison of those characters considered to be most
useful when separating ‘Swinhoe’s dealbatus’
from Kentish Plover. After publication, several additional reports
were received involving birds seen and photographed in China, Vietnam,
Thailand and Singapore. These, together with specimens, form the basis
of the individual country summaries below.
China
Specimens examined are dated from the period spanning April to July,
which would be the likely breeding season. These include 18 from Amoy
[Xiamen, Fujian province], one from Swatow [Shantou, Guangdong province],
nine from Kouang-Tcheou-Wan [Zhanjiang, Guangxi province], plus four
birds collected on Hainan in March, which could also be breeding birds.
In addition, there is the specimen from Macao [Macau] dated 30 January
1906, representing the only winter record from China. Recent reports
from China depict what appears to be a worn adult, photographed at
Sanya, at the southern tip of Hainan, on 12 July 2007 (see http://www.wwfchina.org/birdgallery/showpic.shtm?id=41638
and http://www.wwfchina.org/birdgallery/showpic.shtm?id=41639),
while J. Wilkins (in litt. 2008) reported two birds at Sanya on 19
May 2000. In addition, a photograph of a male at Beihai, Guangxi,
on 25 May 2005, appears at http://www.wwfchina.org/birdgallery/showpic.shtm?id=9234.
Currently, Xiamen
marks the northern limit of the known range of ‘Swinhoe’s
dealbatus’, although there are no recent reports
from there. There are also no reports from Hong Kong, which lies
approximately 500 km to the south-west of Xiamen. Migrant shorebirds
have been studied extensively in Hong Kong since the late 1970s,
and the lack of recent reports suggests few, if any, occur there.
Vietnam
Four specimens collected at Thuan An, Hué, Central Annam,
Vietnam, during the Third Expedition to French Indo-China, in September
and November 1925, and April 1926 (Delacour et al. 1928), are housed
in the collection at NHM. In addition, photographs show at least
seven birds at Phan Thiet, South Annam, on 27 December 2005 (B.
Anderson in litt. 2007) and at least nine were photographed
there on 20 November 2007 (H. Stamm in litt. 2008).
Thailand
We have examined one specimen from Thailand, collected at Khao Sam
Roi Yot, Prachuap Khiri Khan, on 8 November 1932 and housed in the
USNM collection, Washington DC. Following the publication of Bakewell
and Kennerley (2007), several reports supported by photographic
evidence were received. These include a male photographed at Nopparat
Thara Beach, northwest of Krabi, Krabi province, on 17 February
2003 (P. Backman in litt. 2008), followed by a flock of
seven, photographed at Karon Beach, Phuket, 15 November 2003 (P.
Lehikoinen in litt. 2008). In the Gulf of Thailand, several
reports have come from Laem Phak Bia, Phetchaburi, where R. Wardle
(in litt. 2008) photographed a male on 29 January 2004.
Next came a male in March 2007 (G. Bakker and R. van der Vliet
in litt. 2007), followed by one, supported by photographs,
from S. Daengphayon and Somchai Nimnuan on 15 December 2007. Up
to three birds remained here until February 2008 (P. Ericsson, PDR,
Pinit Saengkaew, K. Sutasha, C.-J. Svensson, C. Thomas and D. Walsh
in litt. 2008) and at least one was still present on 23 March
(V. Picken in litt. 2008). Other recent sightings from
Thailand include one at Bang Berd Bay, Patiu district, Chumphon,
east coast of peninsular Thailand, on 26 January 2008 (Smith Sutibut
in litt. 2008), four at Thai Muang Beach, Phang Nga area,
south Thailand on 22 February 2008 (C. Thomas in litt.
2008), a male at Nopparat Thara Beach, Krabi, on 26 and 29 March
2008 (J. Buckens in litt. 2008) and a male at Ko Libong,
Trang, on 6 and 7 April 2008 (Somchai Nimnuan and PDR). |
Figure
1. Map showing location of all documented occurrences of
‘Swinhoe’s dealbatus’ Charadrius [alexandrinus]
dealbatus up to April 2008. Documented sightings (open circles)
have been reported from the following locations: 1 Beihai, Guangxi
province, China; 2 Sanya, Hainan, China; 3 Phan Thiet, Vietnam; 4
Laem Phak Bia, Phetchaburi, Thailand; 5 Bang Berd Bay, Patiu district,
Chumphon, Thailand; 6 Thai Muang Beach, near Phang Nga, Thailand;
7 Karon Beach, Phuket, Thailand; 8 Nopparat Thara Beach, Krabi, Thailand;
9 Ko Libong, Trang, Thailand; 10 Tanjung Tokong, Penang, Malaysia;
11 Kapar Power Station, Selangor, Malaysia; 12 Tuas, Singapore; 13
Changi Cove, Singapore. 14 Cemara, Jambi province, Sumatra. Specimen
records (solid circles) have come from: A Amoy [Xiamen, Fujian Province,
China]; B Swatow [Shantou, Guangdong province, China]; C Macau; D
Kouang-Tcheou-Wan [Zhanjiang, Guangxi province, China]; E Hainan,
China; F Thuan An, Hue Vietnam; G Khao Sam Roi Yot, Prachuap Khiri
Khan, Thailand; H Pulau Langkawi, Malaysia; I Batu, Selangor, Malaysia. |
Malaysia
We have located five specimens from Malaysia. Three specimens, collected
from Pulau Langkawi in the extreme north-west of the country are
housed in USNM, Washington DC. Two were collected here on 1 December
1899 and the third was collected on 14 November 1963. The remaining
two specimens are held in the Raffles Collection at the University
of Singapore, and were collected on 26 November 1906, and labelled
Batu, Selangor, Malaya. Although the location of Batu is uncertain,
D. Wells (in litt. 2007) comments that Batu refers to a
‘rock’ or ‘milestone’, and he had also attempted
to locate this site. Although he could not be certain, he considers
it most likely to refer to a location on the northern Selangor coast,
to the seaward side of Sungei Buloh, and to the north of Jeram beach,
where there is a large limestone outcrop.
The first recent
record, supported by a field sketch, was made by C. Rose who watched
a bird in the roost at Kapar Power Station, Selangor, in March 1993.
Observations by DNB during winter 2006–2007, supported by
photographs, established that a flock of up to 12 birds wintered
on an extensive land reclamation site at Tanjung Tokong, Pulau Pinang.
The first bird was noted on 11 October 2006, after which numbers
increased to a peak of 12 in December, followed by a decline to
five in February, and the last bird was seen on 28 March 2007. The
first returning bird was located on 21 September 2007, and up to
six were present in January 2008.
Singapore
Up to four birds which spent the winter on the extensive land reclamation
site at Tuas, at the western extremity of Singapore bordering the
Straits of Malacca, from late October 1993 to 14 March 1994, were
described and sketched by PRK. There were no further reports from
Singapore until J. Cheah (in litt. 2007) photographed two
males at Changi Cove, on 12 February 2007, and posted images on his
website (http://www.pbase.com/wkcheah/
kentish_plover). A visit to this site on 8 February 2008 revealed
eight birds, and at least 14 there on 17 February, falling to three
on 13 March and just one on 22 March 2008 (M. Kennewell, S. Cockayne
and Wang Luan Keng in litt. 2008).
Sumatra,
Indonesia
A male was trapped at Cemara, Jambi province, Sumatra on 12 February
2008. (I. Londo/WCS in litt. 2008).
Breeding
and wintering ranges
Based on the established identifications above, the breeding range
of ‘Swinhoe’s dealbatus’ remains uncertain.
There is no evidence to suggest that breeding occurs outside the
range given by Swinhoe, i.e. the south coast of China including
Hainan. But with no evidence of passage through Hong Kong, breeding
may no longer occur in Guangdong or Fujian provinces. There is no
evidence to suggest that ‘Swinhoe’s dealbatus’
has occurred in Taiwan and observers there are unfamiliar with it
(S. Liao verbally 2007), contra Swinhoe (1863) who included Formosa
[Taiwan] within the range of dealbatus.
Outside the
breeding season, recent photographic evidence has established that
‘Swinhoe’s dealbatus’ winters locally
along the coast from southern Vietnam, through the Gulf of Thailand
and south along the west coast of the Malay Peninsula to Singapore,
and the east coast of Sumatra, Indonesia. Undiscovered wintering
sites may exist along the sandier east coast of the Thai-Malay Peninsula,
and the underwatched coasts of Vietnam and Sumatra may holder larger
wintering populations. |
HABITAT
Outside the breeding season, ‘Swinhoe’s dealbatus’
appears to show a distinct preference for coastal sites with an
open aspect, which it requires for roosting and feeding. Natural
sites such as the sandy spit at Laem Phak Bia, Thailand, are favoured
for both roosting and feeding, and birds are present there throughout
the day. Land reclamation sites with a sandy substrate and little
or no emergent vegetation, such as Tuas and Changi Cove, Singapore,
are presumably unsuitable for feeding and are used for roosting
during the day. However, these birds depart the site at dusk and
return the following morning, presumably to visit unknown feeding
sites (DNB pers. obs.). At Tanjung Tokong, Penang, Malaysia, the
preferred habitat was a fine sandy substrate, almost completely
devoid of vegetation, which was used as a high tide roost for shorebirds.
When not roosting, however, these birds fed on the adjacent intertidal
mudflats.
It seems likely
that land reclamation sites represent a suboptimal habitat, and
observations in Thailand and Malaysia show that ‘Swinhoe’s
dealbatus’ prefers sand beaches to mudflats. |
BEHAVIOUR
AND ECOLOGY
At both Tanjung Tokong and Tuas, dealbatus usually associated
with Kentish Plovers when feeding and roosting, although they tended
to feed on harder, sandier substrates, while Kentish Plovers would
feed in softer mud along tidal channels. During low tide at Tanjung
Tokong, the mixed plover flock would feed on the tideline, on or near
an isolated sandbar in the middle of extensive mudflats. On occasion,
they were seen to hunt prey (possibly crabs) in a manner typical of
Greater Sand Plover C. leschenaultii: head lowered, dashing
rapidly across the sand to seize the prey before it could retreat
into its burrow. P. Ericsson (in litt. 2008) also commented
that at Laem Phak Bia, Thailand, ‘Swinhoe’s dealbatus’
seem to prefer the more isolated sandy beaches also frequented by
Malaysian Plovers. One male observed for over an hour was very aggressive
and would promptly chase off any Kentish Plover or Sanderling Calidris
alba which approached it too closely. When feeding, both ‘Swinhoe’s
dealbatus’ and Malaysian Plover are more active than
Kentish Plover, and often run almost non-stop while foraging along
the tide edge, where they have been observed chasing down and eating
small crabs (M. Andrews in litt. 2008).
Differences in feeding posture may also be significant. When feeding,
Kentish Plover assumes a rather horizontal stance, with the head held
hunched into the ‘shoulders’. In contrast, ‘Swinhoe’s
dealbatus’ often adopts a slightly more upright stance,
with more of the neck visible.
On the rising tide, feeding shorebirds at Tanjung Tokong congregated
in a loose mixed flock, prior to roosting. As the mudflats were covered,
the flock selected the same roost site each day, with ‘Swinhoe’s
dealbatus’ always preferring open areas devoid of vegetation
and with a sandier, drier substrate. Roosting occurred both on the
foreshore and on bare reclaimed land at the edge of a construction
site. When roosting, dealbatus showed a propensity to sit
on the sand, legs folded beneath the body and head held low. Frequently,
they selected an area with larger stones and hollows into which they
could crouch and which would conceal them wholly or in part. In contrast,
while some Kentish Plovers also roosted in this manner, they were
as likely to roost standing up. When disturbed at the roost, dealbatus
appeared more nervous and tended to run away fast from the disturbance,
whereas Kentish would adopt a peculiar robotic mincing gait, not retreating
as rapidly as ‘Swinhoe’s dealbatus’. |
VOCALISATIONS
Our observations suggested that dealbatus is largely silent during
the non-breeding months. Three birds disturbed by DNB on 19 January
2007, gave an alarm call as they took flight, described as ‘a
high-pitched tip, sometimes tee’, very similar to that of Kentish
Plover. All vocalisations heard were similar to those of Kentish Plovers
and markedly distinct from the more trilling calls of Malaysian Plover.
Like other Charadrius, it is likely that they will have a ‘display
song’ which is given on the breeding grounds, but this has not
yet been recorded. |
CONSERVATION
With all recent reports coming from outside the breeding season, it
is unclear whether ‘Swinhoe’s dealbatus’
faces any immediate threats. With many coastal land reclamation schemes
in Asia, there would appear to be a plentiful supply of suitable,
albeit temporary, wintering sites. Circumstances in the breeding areas
are unknown. But with massive coastal degradation occurring in coastal
southern China, it seems inevitable that breeding areas must have
been lost. Furthermore, if beaches are the preferred habitat during
the breeding season, these will come under increasing pressure from
China’s developing tourist infrastructure, particularly in Hainan
and Guangxi provinces. The rapid and on-going destruction of much
of the coast of southern China does not bode well for the long-term
future. |
CONCLUDING
REMARKS
Few birds can have had such a confused history as Aegialites
[Charadrius] dealbatus. It is remarkable that this rather distinctive
plover has been overlooked for so long in such a well-watched region.
Both Singapore and Malaysia have a long history and strong tradition
of bird-related research, extending back almost two centuries to
the founding of Singapore. Similarly, it is surprising that this
plover has been overlooked for so long in Thailand, also a centre
for bird research and a popular destination for visiting ornithologists
and birders since the 1970s. Undoubtedly, the close resemblance
of ‘Swinhoe’s dealbatus’ to ‘eastern’
Kentish Plover in non-breeding plumage, and passing similarity to
Malaysian Plover when in breeding plumage, has contributed to this
confusion and masked its true status. Furthermore, its omission
from modern field guides has not encouraged observers to question
the appearance of those ‘funny’ Kentish Plovers they
have encountered.
What has become
apparent from the above discussion is that the taxon referred to
here as ‘Swinhoe’s dealbatus’ has completely
disappeared from the modern ornithological literature, and its place
taken by ‘eastern’ Kentish Plover. Consequently, the
name dealbatus has been erroneously applied to ‘eastern’
Kentish Plover by almost all authorities and authors throughout
much of the twentieth century. Currently not a single taxonomic
authority, handbook or field guide recognises the distinctive appearance
of ‘Swinhoe’s dealbatus’.
Based on comparisons
of morphological, structural and behavioural differences, ‘Swinhoe’s
dealbatus’ is consistently diagnosable from Kentish
and Malaysian Plovers at all ages and in all plumages. At present,
the breeding ranges of ‘Swinhoe’s dealbatus’ and
‘eastern’ Kentish Plover in eastern China are believed
to be allopatric. However, contemporary accounts, including that
of La Touche (1931–1934), allude to the possibility that the
breeding ranges may have overlapped in northeast China, and further
work is required to establish whether this is the case. Research
to investigate the phylogenetic relationships of ‘Swinhoe’s
dealbatus’ with Kentish and Malaysian Plovers is currently
proceeding and the results will appear shortly.
It is hoped
that the publication of this paper will rectify these taxonomic,
historical and nomenclatural errors and reinstate ‘Swinhoe’s
dealbatus’ as the distinctive taxon described here.
If ‘Swinhoe’s dealbatus’ proves to be
a valid species, it is recommended that the name Charadrius
dealbatus be reinstated with the English name White-faced Plover
applied for popular usage. Furthermore, it is also
recommended that the available name Charadrius alexandrinus
nihonensis be reinstated for the large-billed ‘eastern’
Kentish Plovers breeding in northern Japan, Sakhalin and the southern
Kuril Islands.
Finally, we
repeat the appeal in Bakewell and Kennerley (2007, 2008) for anyone
with past or future records and photographic evidence of ‘Swinhoe’s
dealbatus’ to contact us, particularly from the period
spanning March–July, and from anywhere in China.
Note
added in proof
On 7–9 June 2008, members from the Hong Kong and Fujian Bird
Watching Societies visited the Minjiang River mouth near Fuzhou,
Fujian province, China, where several pairs of ‘Swinhoe’s
dealbatus’ were found to be breeding (M. and P. Wong,
and K. C. Lee in litt. 2008). |
ACKNOWLEDGEMENTS
We are particularly grateful to Geoff Carey, Richard Chandler, Nigel
Collar, John Howes, James Kennerley, Angus Lamont, Paul Leader, Brian
Small, Subaraj Rajathurai and David Wells for their suggestions, comments,
advice and enthusiasm during the preparation of this paper. Our thanks
also go to Robert Prys-Jones, Mark Adams and Katrina Cook who kindly
allowed access to the specimen collection at NHM, Tring, to Alison
Harding for locating many of the more obscure references quoted, and
to Chutammas Sukhontapatipak for help in preparing the map. Robert
Prys-Jones, Edward Dickinson and Steven Gregory clarified nomenclatural
issues associated with the selection of a lectotype and the naming
of dealbatus, and Mike Wilson provided Russian reference details.
Wang Luan Keng and Kelvin K. P. Lim, (Raffles Museum of Biodiversity
Research, Department of Biological Sciences, Faculty of Science, National
University of Singapore), kindly arranged for the loan of specimens
to NHM. Brian Schmidt (Smithsonian Institution, Div. of Birds, Washington
DC, USA), and Hein van der Grouw (National Museum of Natural History,
Leiden), kindly provided images of Kentish Plover specimens collected
by Swinhoe and held in their respective collections. Without their
help, the listing of paralectotypes would be incomplete. In addition,
Margaret Hart and Mary LeCroy (American Museum of Natural History,
New York), Iris Heynen (Museum für Naturkunde, Berlin), Henry
McGhee (Manchester Museum) and Nathan H. Rice (Academy of Natural
Sciences, Philadelphia) responded to our requests for information.
Professor Tamás Székely and Clemens Küpper from
the Biodiversity Laboratory of the University of Bath, and Dr Pat
Lee, Department of Biological Sciences Swansea University, recommended
methods by which we could work towards establishing the molecular
phylogeny of these birds. Thanks also go to Andy Birch who agreed
to publish the earlier article on the Surfbirds website (Bakewell
and Kennerley 2007), which encouraged observers to seek out these
birds and submit their sightings to us.
In addition, we are extremely grateful to the many people mentioned
below who provided details of their observations, together with comments
and opinions, in response to our request for information, with apologies
to anyone inadvertently omitted. Singapore: Jonathan Cheah provided
details of his February 2007 sighting. Wang Luan Keng (NUS), Ramakrishnan
and Lin Yangchen (National Parks, Singapore), together with Martin
Kennewell and Simon Cockayne, supplied details of sightings made at
Changi Cove, and are also thanked for their efforts to try to trap
birds there. Malaysia: Chris Rose provided details and a sketch of
a bird at Kapar Power Station Ash Lagoons. Associate Professor Shahrul
Anuar bin Mohd Sah, School of Biological Sciences, Universiti Sains
Malaysia, M. A. Muin, Unisains, Universiti Sains Malaysia, and Hasnan
Yusop, Director, Department of Wildlife and National Parks, Pulau
Pinang, are thanked for their help in attempts to trap the birds at
Tanjung Tokong. Indonesia: Iwan Londo/WCS provided details and photographs
of a male trapped at Cemara, Jambi province, Sumatra. Thailand: Peter
Backman, Garry Bakker, Johan Buckens, Suchart Daengpayon, Peter Ericsson,
Petteri Lehikoinen, Somchai Nimnuan, Verity Picken, Pinit Saengkaew,
Smith Sutibut, Carl-Johan Svensson, Craig Thomas, Rinse van der Vliet,
David Walsh and Robert Wardle provided details of their sightings,
some dating back to 2003. Vietnam: We thank Bjorn Anderson and Hanno
Stamm for providing details of sightings at Phan Thiet. China: John
Wilkins supplied details of his sighting at Sanya, Hainan. Bjorn Anderson
and Jesper Hornskov provided links to websites which included photographs
of Kentish Plovers, including breeding birds in China, and also shared
their opinions on these birds. We also thank an anonymous correspondent
in China who provided details of a bird photographed at Beihai, Guangxi
province. Others: Ed Keeble and Frederic Jiguet commented
on, and provided links to images of pale Kentish Plovers photographed
in the Middle East. |
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the Third Expedition to French Indo-China. Ibis (12)5:
23–
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526–534.
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A. (1967) On the validity of Charadrius alexandrinus javanicus
Chasen and the occurrence of Charadrius alexandrinus
ruficapillus Temm. and of Charadrius peronii Schl.
on Java and in New Guinea. Philippine J. Sci. 95:
209–214.
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156–240. |
APPENDIX
1
List of all known specimens of Charadrius [alexandrinus] dealbatus.
Examined specimens are at NHM, Tring; USNM, Washington; the National
Museum of Natural History (RMNM), Leiden, and the Raffles Museum of
Biodiversity Research at the National University of Singapore, and
identification verified. All locations denoted appear as written on
the original collection labels. Note that location names have changed
as follows: Amoy [Xiamen, Fujian province, China]; Swatow [Shantou,
Guangdong province, China]; Kouang-Tcheou-Wan [Zhanjiang, Guangxi
province, China]; Sam Roi Yot, Siam [Khao Sam Roi Yot, Prachuap Khiri
Khan, iThailand]; Pulo Lankawi [Pulau Langkawi, Malaysia].
Specimen
No. |
Collection |
Location |
Date |
Sex/Age |
Collectors
(s) |
16D |
NHM,
Tring |
Amoy |
1861 |
Male |
Swinhoe |
91.10.1.692 |
NHM,
Tring |
Amoy |
June
1866 |
Male |
Swinhoe |
91.10.1.693 |
NHM,
Tring |
Amoy |
August
1861 |
Male |
Swinhoe |
93.1.25.193 |
NHM,
Tring |
Amoy |
May
1861 |
Male |
Swinhoe |
93.1.25.194 |
NHM,
Tring |
Amoy |
May
1861 |
Female |
Swinhoe |
96.7.1.559 |
NHM,
Tring |
Amoy |
May
1861 |
Male |
Swinhoe |
96.7.1.560 |
NHM.
Tring |
Amoy |
May
1861 |
Male |
Swinhoe |
96.7.1.561 |
NHM,
Tring |
Amoy |
June
1866 |
Male |
Swinhoe |
96.7.1.562 |
NHM,
Tring |
Amoy |
June
1866 |
Male |
Swinhoe |
96.7.1.567 |
NHM,
Tring |
Amoy |
June
1866 |
Female |
Swinhoe |
96.7.1.568 |
NHM,
Tring |
Amoy |
4
July 1866 |
Male |
Swinhoe |
96.7.1.569 |
NHM,
Tring |
Amoy |
4
July 1866 |
Female |
Swinhoe |
96.7.1.573 |
NHM,
Tring |
Hainan |
March
1868 |
Male |
Swinhoe |
96.7.1.574 |
NHM,
Tring |
Hainan |
March
1868 |
Male |
Swinhoe |
96.7.1.575 |
NHM,
Tring |
Hainan |
March
1868 |
Male |
Swinhoe |
1908.1.8.222 |
NHM,
Tring |
Swatow |
2
July 1888 |
Female |
Styan |
1910.5.2.57 |
NHM,
Tring |
Macau,
China |
30
Jan 1906 |
Female |
Vaughan |
1926.9.8.203 |
NHM,
Tring |
Thuan
An, Hue, Vietnam |
22
Sep 1925 |
Juvenile |
Delacour
& Lowe |
1926.9.8.204 |
NHM,
Tring |
Thuan
An, Hue, Vietnam |
25
Nov 1925 |
Juvenile |
Delacour
& Lowe |
1926.9.8.212 |
NHM,
Tring |
Thuan
An, Hue, Vietnam |
22
Sep 1925 |
Male |
Delacour
& Lowe |
1927.6.5.256 |
NHM,
Tring |
Thuan
An, Hue, Vietnam |
11
Apr 1926 |
Male |
Delacour
& Lowe |
1935.10.23.74 |
NHM,
Tring |
Kouang-Tcheou-Wan |
17
May 1932 |
Female |
Delacour
and Jabouille |
1935.10.23.75 |
NHM,
Tring |
Kouang-Tcheou-Wan |
17
May 1932 |
Female |
Delacour
and Jabouille |
1935.10.23.76 |
NHM,
Tring |
Kouang-Tcheou-Wan |
18
May 1932 |
Male |
Delacour
and Jabouille |
1935.10.23.77 |
NHM,
Tring |
Kouang-Tcheou-Wan |
25
May 1932 |
Female |
Delacour
and Jabouille |
1935.10.23.78 |
NHM,
Tring |
Kouang-Tcheou-Wan |
18
May 1932 |
Male |
Delacour
and Jabouille |
1935.10.23.79 |
NHM,
Tring |
Kouang-Tcheou-Wan |
29
June 1932 |
Male |
Delacour
and Jabouille |
1935.10.23.80 |
NHM,
Tring |
Kouang-Tcheou-Wan |
1
Jul 1932 |
Juvenile |
Delacour
and Jabouille |
1935.10.23.81 |
NHM,
Tring |
Kouang-Tcheou-Wan |
3
Jul 1932 |
Female |
Delacour
and Jabouille |
1935.10.23.238 |
NHM,
Tring |
Kouang-Tcheou-Wan |
27
Jul 1933 |
Female |
Delacour
and Jabouille |
107075 |
USNM |
Amoy |
Jun
1866 |
Male |
Swinhoe |
113342 |
USNM |
Hainan |
Mar
1868 |
Unknown |
Swinhoe |
113345 |
USNM |
Amoy |
4
Jul 1866 |
Female? |
Swinhoe |
113346 |
USNM |
Amoy |
4
Jul 1866 |
Male? |
Swinhoe |
113347 |
USNM |
Amoy |
1861 |
Unknown |
Swinhoe |
332671 |
USNM |
Sam
Roi Yot, Siam |
8
Nov 1932 |
Male |
Smith |
172915 |
USNM |
Pulo
Lankawi |
1
Dec 1899 |
Female |
Abbott |
172917 |
USNM |
Pulo
Lankawi |
1
Dec 1899 |
Unknown |
Abbott |
486810 |
USNM |
Pulau
Langkawi, Malaysia |
14
Nov 1963 |
Female |
Gill |
155918 |
RMNH |
Amoy |
April
1861 |
Female |
Swinhoe |
155919 |
RMNH |
Amoy |
April
1861 |
Female |
Swinhoe |
ZRC
3.2540 |
Raffles |
Batu,
Selangor, Malaya |
26
Nov 1906 |
Male |
Unknown |
ZRC
3.2541 |
Raffles |
Batu,
Selangor, Malaya |
26
Nov 1906 |
Male |
Unknown |
|
APPENDIX
2
List of paralectotypes of Aegialites [Charadrius] dealbatus
held at NHM, Tring; USNM, Washington DC, and the National Museum of
Natural History (RMNH), Leiden. All specimens were collected by Robert
Swinhoe prior to 1870 from the type
locality (i.e. ‘the South coast of China, including Formosa
and Hainan’), and form the basis of his recognition of Aegialites
dealbatus as a distinct taxon (Swinhoe 1870). The lectotype (BMNH
1896.7.1.559) is marked with an asterisk. Due to past confusion, the
taxon dealbatus is a composite, comprising both Aegialites [Charadrius]
dealbatus and Kentish Plover C. alexandrinus. This table
distinguishes between those specimens identified as Aegialites
[Charadrius] dealbatus, listed here as dealbatus; and
those identified as ‘eastern’ Kentish Plover, listed as
alexandrinus. All locations denoted appear as written on
the original collection labels. Note that some location names have
changed as follows: Amoy [Xiamen, Fujian province, China]; Talienwan
[Dalian Bay, Liaoning province, China]; Takow, Formosa [Kaohsiung,
Taiwan]. The location of Oseukeo cannot be traced but may be in Taiwan
where Robert Swinhoe lived from 1856 to 1866.
Specimen
No. |
Location |
Date |
Sex/Age |
Collection |
Taxon |
16D |
Amoy |
1861> |
Male |
NHM,
Tring |
dealbatus |
91.10.1.692 |
Amoy |
June
1866 |
Male |
NHM,
Tring |
dealbatus |
91.10.1.693 |
Amoy |
August
1861 |
Male |
NHM,
Tring |
dealbatus |
93.1.25.193 |
Amoy |
May
1861 |
Male |
NHM,
Tring |
dealbatus |
93.1.25.194 |
Amoy |
May
1861 |
Female |
NHM,
Tring |
dealbatus |
*96.7.1.559 |
Amoy |
May
1861 |
Male |
NHM,
Tring |
dealbatus |
96.7.1.560 |
Amoy |
May
1861 |
Male |
NHM.
Tring |
dealbatus |
96.7.1.561 |
Amoy |
June
1866 |
Male |
NHM,
Tring |
dealbatus |
96.7.1.562 |
Amoy |
June
1866 |
Male |
NHM,
Tring |
dealbatus |
96.7.1.567 |
Amoy |
June
1866 |
Female |
NHM,
Tring |
dealbatus |
96.7.1.568 |
Amoy |
4
July 1866 |
Male |
NHM,
Tring |
dealbatus |
96.7.1.569 |
Amoy |
4
July 1866 |
Female |
NHM,
Tring |
dealbatus |
96.7.1.573 |
Hainan |
March
1868 |
Male |
NHM,
Tring |
dealbatus |
96.7.1.574 |
Hainan |
March
1868 |
Male |
NHM,
Tring |
dealbatus |
96.7.1.575 |
Hainan |
March
1868 |
Male |
NHM,
Tring |
dealbatus |
107075 |
Amoy |
Jun
1866 |
Male |
USNM |
dealbatus |
113342 |
Hainan |
Mar
1868 |
Unknown |
USNM |
dealbatus |
113345 |
Amoy |
4
Jul 1866 |
Female? |
USNM |
dealbatus |
113346 |
Amoy |
4
Jul 1866 |
Male? |
USNM |
dealbatus |
113347 |
Amoy |
1861 |
Unknown |
USNM |
dealbatus |
155918 |
Amoy |
April
1861 |
Female |
RMNH |
dealbatus |
155919 |
Amoy |
April
1861 |
Female |
RMNH |
dealbatus |
4.25 |
Amoy |
1861 |
Male |
NHM,
Tring |
alexandrinus |
4.3 |
Amoy |
Aug
1861 |
Male |
NHM,
Tring |
alexandrinus |
5.55 |
Amoy |
Jan
1860 |
Male? |
NHM,
Tring |
alexandrinus |
91.10.1.694 |
Amoy |
1861 |
Unknown |
NHM,
Tring |
alexandrinus |
91.10.5.157 |
North
Formosa |
Mar
1862 |
Unknown |
NHM,
Tring |
alexandrinus |
93.1.25.195 |
Amoy |
Oct
1866 |
Female |
NHM,
Tring |
alexandrinus |
93.1.25.196 |
Amoy |
Oct
1866 |
Unknown
|
NHM.
Tring |
alexandrinus |
93.1.25.197 |
Amoy |
Jan
1867 |
Juvenile |
NHM,
Tring |
alexandrinus |
93.1.25.198 |
Talienwan |
Jul
1860 |
Unknown |
NHM,
Tring |
alexandrinus |
93.1.25.199 |
South-west
Formosa |
1861 |
Male? |
NHM,
Tring |
alexandrinus |
93.1.25.233 |
Amoy |
Nov
1866 |
Unknown |
NHM,
Tring |
alexandrinus |
93.1.25.234 |
Amoy |
Nov
1866 |
Unknown |
NHM,
Tring |
alexandrinus |
93.1.25.235 |
Amoy |
Nov
1866 |
Female |
NHM,
Tring |
alexandrinus |
93.1.25.236 |
South-west
Formosa |
1861 |
Female |
NHM,
Tring |
alexandrinus |
96.7.1.558 |
Oseukeo |
14
Nov 1857 |
Female |
NHM,
Tring |
alexandrinus |
96.7.1.563 |
Amoy |
Jan
1860 |
Unknown |
NHM,
Tring |
alexandrinus |
96.7.1.564 |
Amoy |
Nov
1866 |
Unknown |
NHM,
Tring |
alexandrinus |
96.7.1.566 |
Amoy |
Nov
1866 |
Unknown |
NHM,
Tring |
alexandrinus |
96.7.1.570 |
Amoy |
Nov
1866 |
Unknown |
NHM,
Tring |
alexandrinus |
96.7.1.572 |
North
Formosa |
Mar
1862 |
Unknown |
NHM,
Tring |
alexandrinus |
93.1.25.192 |
Oseukeo |
14
Nov 1857 |
Unknown |
NHM,
Tring |
alexandrinus |
107076 |
Amoy |
Oct
1866 |
Unknown |
USNM |
alexandrinus |
113343 |
Amoy |
Oct
1866 |
Unknown |
USNM |
alexandrinus |
113344 |
Amoy |
Jun
1866 |
Unknown |
USNM |
alexandrinus |
113348 |
Amoy |
Jan
1860 |
Unknown |
USNM |
alexandrinus |
113349 |
Takow,
Formosa |
Oct
1865 |
Unknown |
USNM |
alexandrinus |
155916 |
China |
April
1861 |
Female |
RMNH |
alexandrinus |
155917 |
China |
Feb
1861 |
Unknown |
RMNH |
alexandrinus |
|
Kindly
submitted by:
Peter Kennerley, 16 Coppice Close, Melton, Suffolk, U.K. IP12
1RX. Email: peterkennerley@onetel.net
David N. Bakewell, c/o Whimbrel Cottage, Wilby, Eye, Suffolk, U.K.
IP21 5LE.
Philip D. Round, Regional Representative, The Wetland Trust and Assistant
Professor, Department of Biology, Faculty of Science, Mahidol University,
Rama 6 Road, Bangkok 10400, Thailand. |
|
|
|