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By Nick Upton 24/03/06
Research
Techniques Assignment 1
BSc (Hons) Wildlife and Countryside Conservation,
Year 2
Note:
This essay is not intended to be a thourough scientific
review of the known ecology of White-eyed
River-Martin nor is intended to by an attack on
the orignal article by Joe Tobias who I hope will
be flattered to know that out of millions of articles
I could have chosen to review it was his that
interested me enough to do so. The remit I was
given for this assignment was to choose an article
from a peer-reviewed publication and write a balanced
critique of it, with the highest grades given
to those who are able to show a high level of
critical thinking and originality. I have included
my work here as I feel that some of the points
I make will be of interest and may stimulate some
thought upon the subject which in turn may contribute
to rediscovering this species if it still exists;
something that was also the intention of the original
article which is reproduced here in the appendices
with kind permission of the Oriental
Bird Club (OBC) and referred to throughout
the essay by paragraph number.
Please
support the OBC's conservation work by visiting
their website and becoming a member.
Contents
1.
Introduction
2.
Literary Style
3.
Factual Accuracy and Analysis
4.
Conclusion
5.
References
6.
Appendices |
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Introduction
Figure
1: White-eyed
River-martin (McClure, No date). |
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Even a cursory glance at one of the few photos
in existence of the White-eyed River-martin
(See figure 1) immediately conveys a feeling
that it is a special creature, indeed, it
has something about it that makes one wonder
if it is in fact a real species and not a
clever hoax. Add to this its mysterious discovery
and disappearance, and the unusually low number
of these birds that have ever been encountered,
and the result is a bird of almost mythical
proportions. This article attempts to clarify
some of the facts that have become clouded
since its discovery in 1968 (Thonglongya),
to summarize the speculation surrounding its
ecology and taxonomy, to rekindle hope that
it may be rediscovered by proposing areas
where it may persist and ultimately to introduce
a new generation of ornithologists to a little-known
and neglected species. To achieve this, the
author employs a blend of historical narrative,
extrapolation and speculation from scientific
fact with an informal style of writing.
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Literary
Style
From the beginning of the article the author attempts,
rather successfully, to create an almost fairy-tale
like atmosphere, giving the reader an early sense
of how mysterious this species is and by using vocabulary
such as “spectacular”, “enigma”,
“mythical” and “cryptic”
from start to finish, the reader is constantly reminded
of this theme. This element of mystery is created
by placing the reader at the scene of discovery,
making one feel part of the story from the first
paragraph; setting the scene for suggesting that
the reader has a part to play in the rediscovery
of the species towards the latter stages of the
discussion. By employing this style, the author
has created a connection between the reader and
the River-martin that not only results in reading
the article to completion, but hopefully continues
beyond by stimulating the reader to interpret the
facts in their own way and to make further research
into the subject. A discussive style of writing
also helps to keep the reader at the centre of the
article and by asking questions before answering
them (Paragraph 7), it almost feels like one is
having a conversation rather than reading an article.
The system of referencing by numbers adds to this
high level of readability, maintaining the flow
of the argument without confusing the eye with large
amounts of names in brackets or italics, although
this is contrary to the system used by many authors.
These points all draw the reader further into
the article once it has been commenced, but a
certain aspect of the layout does not add to its
attraction; there are no sub-headings to break
the script into more digestible chunks for the
reader with lower powers of concentration. It
might be useful for the author to use headings
such as “Discovery”, Ecology”
or “Where to look” to give the reader
an at-a-glance summary of the topic of each section.
This is a minor point, but as it seems that widening
the awareness of the White-eyed River-martin is
an aim of the article it would seem sensible to
employ tactics designed to attract as large an
audience as possible.
Although the style of writing is largely excellent
in terms of the atmosphere it creates and in its
clarity, the second paragraph is uncharacteristically
unclear in the way it attempts to explain that
knowledge of the precise site of discovery may
not be as reliable as is often stated. This is
cleared up in the third paragraph, but it remains
that the information in paragraph two is rather
clumsily delivered. By using the words “Bung”
and “Nong”, an assumption that the
reader has some knowledge of the Thai language
is made and this is ill-advised, further confusing
the point, and when a poor translation is also
used (fen would be more appropriate (Pers. Obs.;
SE-Education, 2002; Phiromyothee, 2006)) it does
not help the reader paint a clear picture of the
site of discovery.
Paragraph
two apart, the style of the article is interesting,
it is easy to understand and very readable.
Factual
Accuracy and Analysis
Before
examining the factual content of the article,
or any of the explanations it offers, it should
be praised for bringing the story of the River-martin
to a wider audience. If the reader is tempted
to further his research on the subject, it immediately
becomes clear how difficult this is to achieve
with most of the referenced articles being difficult
to obtain due to their age or storage in Thai
libraries. In this respect, this article does
a wonderful job of bringing the entire White-eyed
River-martin story a new level of accessibility
through the traditional media of scientific bulletin
and, for the first time, through the internet.
The
first nine paragraphs of the article outline the
circumstances surrounding the discovery and disappearance
of the species, and these facts are hard to dispute.
Indeed, the author does a good job of questioning
the accuracy of what has been long taken for fact,
highlighting that the original research team never
actually saw the species in the field (Paragraph
3). The author does, however, fall short of specifically
pointing out that this included Kitti Thonglongya,
who originally described the species (Birdlife
International, 2001); this point would have given
weight to the theme of keeping an open mind to
the accuracy of some of the original reporting.
Whilst speculating on the location of roosting
Barn Swallows Hirundo rustica, and consequently
where the River-Martin might be located, the author
does well to highlight the changing ecology of
Beung (Bung) Boraphet due to lotus harvesting
(Paragraph 9), but completely omits to mention
that the fen was totally drained of water in 1959
and 1972 (Jintanugool & Round, 1989) and again
in the early 1990s (Stewart-Cox, 1995), with further
disturbances during this latter period (Round,
1990). These facts have surely effected the stability
of the ecosystem and could prove critical to whether
the site remains suitable for White-eyed River-Martin.
This section of the article also informs the reader
that a reserve ranger was killed by poachers at
Beung Boraphet; very useful in providing an insight
into the problems of conservationists in Asia,
as well as rather macabrely adding to the mystique
of the narrative. |
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Figure
2: African River-Martin (Sinclair,
2004). |
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The remainder of the article discusses the
possible ecology of this species in order
to speculate upon where rediscover might occur,
and in doing so draws the reader’s attention,
in paragraph 10, to another little-known species,
the African River-Martin Pseudochelidon
eurystomina. As the closest relative
of White-eyed River-martin this is a natural
progression of the discussion, but despite
providing excellent photos of sirintarae
there is no image of eurystomina
for comparison (See figure 2); whilst this
is not a necessity it would be of interest
to the reader. Having invited comparison with
the African species, the author fails, at
this point, to explore this line of thinking
further, instead a summary of what can be
inferred from the few specimens ever studied
is provided. |
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These facts are of obvious merit, however, it
would make sense to alert the reader to these
before suggesting a look at African River-Martin
and then to subsequently discuss its affinities
to sirintarae in entirety.
Speculation
based upon African River-Martin’s behaviour
is made without properly discussing the most critical
point when assessing the merits of this theme;
in which genera are the two species to be placed?
Mentioned in only fragmentary form, in paragraph
four and in the penultimate paragraph, is the
fact that some authors consider sirintarae
deserving of its own genus and others consider
it congeneric with eurystomina. To so
briefly deal with this issue, and in broken fashion,
would seem rather a pity, as the two species’
similarity, or difference, is vital when assessing
the possible ecology and behaviour of White-eyed
River-Martin; issues that are critical when speculating
upon where it might be rediscovered due to the
scarcity of factual information. Presumably this
author considers that sirintarae should
be placed in the genus Eurochelidon as
this is the taxonomy used in the article’s
title, but no explanation as to why this view
has been taken is given other than a few anecdotal
observations (Paragraph 4). Perhaps this is because
this view does not really hold up to scrutiny;
on re-analysis of the data taken from the original
samples there is apparently no significant difference
in the bill measurements of the two species (Zusi,
1978), previously the only non anecdotal evidence
for different feeding ecologies and thus different
genera (Turner & Rose, 1994). When it is also
taken into account that the decision to place
sirintarae in its own genus was based
on data from just nine to twelve samples, certainly
not enough to be conclusive, it may explain the
author’s reluctance to discuss this issue.
Whilst the author does well to encourage the reader
to keep an open mind regarding the behaviour and
ecology of White-eyed River-Martin throughout
this section of the article, he might do better,
considering the lack of evidence to the contrary,
to concentrate on using African River-Martin as
a model when considering the habits of the Asian
species.
The
article does in fact follow this theme up to a
point, going on to propose regions that would
most likely harbour this elusive species if it
still exists, and this optimistic aspect is vital
for the article to inspire any ornithological
expeditions. Assumptions about sirintarae’s
ecology here are indeed drawn from knowledge of
African River-Martin in that large river systems
(Turner & Rose, 1995; Birdlife International,
2000) are deemed the most likely regions to examine;
with rivers in Thailand, Myanmar, China, Laos
and Cambodia all suggested. The author does well
to name the last of these as since publication
there have been possible, if unconfirmed, sightings
of White-eyed River-Martin there (Silver, 2003;
Judell, 2006). However, this is simply recycling
established views and although the stated aim
is just this; “to compile our knowledge”
(Paragraph 1), the author would be well advised
to provide a new interpretation to improve the
chances of achieving another stated aim; “in
hope that it might lead to a dramatic rediscovery”
(Paragraph 1). Indeed, it is here that the author,
having made comparisons with the African species,
stops short of further extrapolation; it is known
that the African River-Martin breeds inland and
migrates down the Congo river to winter in coastal
regions (Birdlife International, 2000; Birdlife
International 2005), so why not consider that
the Asian species behaves the same? It has often
been suggested that sirintarae might
breed somewhere in China and migrate (Dickinson
& Dekker, 2001), so the author does well to
suggest the Salween, Irrawady and Mekong, but
he would be well advised to consult an atlas to
see that the Yuan in Vietnam would be equally
likely (See figure 3). Indeed, this river, and
the delta of the Mekong, would surely deserve
consideration in respect of the number of scientific
discoveries, and rediscoveries, in Vietnam since
the end of the war. If beasts as large as the
Vu Quang ox (Dung et al., 1995) and Javan
rhinoceros (Newsweek International, 1999) can
go unnoticed then surely there is hope for a bird
as small and as mobile as the White-eyed River-Martin?
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Figure
3: River systems that could harbour
White-eyed River-Martin (Adapted from Microsoft,
2006). |
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A
short article like this does well to touch
upon, if sometimes too briefly, so many issues,
and it may well be the intention of the author
to simply provide a spark to rekindle a forgotten
debate, and in this he has done well. One
issue, though, does not seem to have been
dealt with at all; the possibility that White-eyed
River-Martin might only have ever occurred
in Thailand as a vagrant, something others
have subsequently proposed (Birdlife International,
2001). It is mentioned that the species was
assumed to be regular in this country because
the locals knew it by the name nok ta phong,
“swollen-eyed bird”, however,
this is a name so simple that it could have
been made up on the spot by even a child,
and carries no implication that it is a long-standing
name. The article does observe, though, that
rediscovery is most likely in another country,
but by refusing to outline the possibility
of vagrancy, denies the reader a vital clue
to rediscovering the species. In this theme,
the article
could have gone on to suggest analysing weather
patterns at the time of discovery in 1968
to see if anything unusual occurred. In fact,
this reluctance to discuss vagrancy is perhaps
similar to omitting a full discussion of taxonomy
in its Siamocentricity, a line of thought
that may have held back rediscovery of the
species and may continue to do so. |
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The final paragraph of the article sees the author
back to his best, with a splendidly optimistic
and atmospheric summary of the likelihood that
rediscovery will occur, pointing out the fact
that it escaped ornithologists attention for a
long period before being discovered. The last
sentence, in particular, is well-designed to encourage
the reader to further investigate the species
and possibly claim his “prize”.
Conclusion
This
article does an excellent job in collating the
current knowledge of the species and revealing
avenues of further thought that the reader might
take when considering this species. The style
of writing is interesting, upbeat and atmospheric,
although at times the structure of the discussion
does not seem as logical as it might. The author
does well to draw attention to using the African
River-martin as a comparison, but stops short
of exploring the full range of possibilities this
might lead to, even failing to recognise some
of the basic inferences one might draw from this.
There is also a failure to provide any conclusive
evidence to explain why African and White-eyed
River-Martins should not be considered congeneric;
something that is at the centre of deciding upon
their behavioural similarities or differences
and consequently where the search for sirintarae
might resume.
It
can be said that the author achieves his stated
aim of compiling current knowledge in an informative
and thought-provoking way. By provoking the reader
to question the facts, the author also goes some
way to stimulating the road to rediscovery, but
by not taking the opportunity to follow his train
of thought to its conclusion he fails to make
any ground-breaking speculation of his own to
further this aim. Indeed, since publication a
breakthrough has yet to be made (Butchart et al.,
2005).
References
Birdlife
International (2000). Threatened birds of the
world. Barcelona & Cambridge, UK.
Birdlife
International (2001). White-eyed River-martin
Eurochelidon sirintarae, Red Data
Book; Threatened Birds of Asia. Online at
http://www.rdb.or.id/detailbird.php?id=257
[Accessed 21/02/06].
Birdlife
International (2005). African River-martin; Birdlife
Species Factsheet, Birdlife International
website. Online at http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=70
[Accessed 22/03/06].
Butchart,
S.H.M., Collar, N.J., Crosby, M.J & Tobias,
J.A. (2005). Asian Enigmas: “Lost”
and poorly-known birds: top targets for birders
in Asia, Birding Asia-Bulletin of the
Oriental Bird Club, No 3, June
2005.
Dung, V.V., Giao, P. M., Chinh, N. N., Tuoc, D.
& MacKinnon, J. (1995). Discovery and conservation
of the Vu Quang ox in Vietnam, Biological Conservation,
Vol 72, No 3, pp 410-410(1).
Jintanugool,
J. & Round, P. D. (1989). Beung Boraphet,
Asean Regional Centre for Biodiversity Conservation
(ARCBC) website. Online at http://www.arcbc.org/wetlands/thailand/tha_beubor.htm
[Accessed 02/03/06].
Judell,
D. (2006). Personal communication.
McClure,
H. E. (No date). Photograph of White-eyed River-martin
reproduced in Tobias, J.A. (2000). Little-known
Oriental bird, White-eyed River-martin Eurochelidon
sirintarae, Oriental Bird Club Bulletin
31; June 2000.
Microsoft
Corporation (2006). Encarta Atlas online.
Online at http://encarta.mas/encnet/features/MapCenter/map.aspx
[Accessed 28/03/06].
Newsweek
International (1999). In Vietnam, a Shot in the
Dark (first photograph of the world’s most
endangered animal, a Javan Rhino in Vietnam).
Newsweek International, July 26, 1999.
Phiromyothee,
S. (2006). Personal communication.
Round,
P. D. (1990). Bird of the month: White-eyed River-martin.
Bangkok Bird Club Bulletin, Vol
7, No1, pp10-11. Cited in Tobias, J.
(2000). Little-known Oriental bird, White-eyed
River-martin Eurochelidon sirintarae,
Oriental Bird Club Bulletin 31;
June 2000.
SE-Education
(2002) SE- ED’s Modern English-Thai
& Thai-English Dictionary (Contemporary
Edition). SE-Education, Bangkok, Thailand.
Silver,
G. (2003) Bangkok Morning/ Prek Tol, Cambodia
Trip Report. Birdchat Website. Online
at http://listserv.ccit.arizona.edu/cgi-bin/wa?A2=ind0302d&L=birdchat&O=D&P=3796
[Accessed 24/03/06].
Sinclair,
I. (2004). Photograph of African River-martin
reproduced in Trip report from Gabon, Sao Tome
& Principe, and Camaeroon, 14 February –
11 March 2004, Tropical Birding website.
Online at http://www.tropicalbirding.com/tripreports/STP-Cameroon-Feb2004FEW-pix.htm
[Accessed 23/03/06].
Stewart-Cox,
B. (1995). Wild Thailand. Asia Books,
Bangkok, Thailand.
Thonglongya,
K. (1968). A new martin of the genus Pseudochelidon
from Thailand. Thai National Scientific Papers,
Fauna Series no 1. Applied Scientific Research
Corporation of Thailand, Bangkok, Thailand. Cited
in Tobias, J. (2000). Little-known Oriental bird,
White-eyed River-martin Eurochelidon sirintarae,
Oriental Bird Club Bulletin 31;
June 2000.
Turner,
A. & Rose, C. (1994). A Handbook to the
Swallows and Martins of the World, Christopher
Helm, London.
Zusi,
R. L. (1978). Remarks on the generic allocation
of Pseudochelidon sirintarae. Bulletin
of the British Ornithology Club, Vol
98, No 1, pp13-15.
Appendices
Appendix 1:
Little known Oriental Bird: White-eyed River-Martin
Eurochelidon sirintarae by Joe Tobias
Paragraph 1 In January
1968, during the course of ringing activities
at a wetland site in south-central Thailand, fieldworkers
discovered a strange swallow amongst large numbers
of migrant hirundines. It proved to be a new species
and was christened the White-eyed River-Martin
Pseudochelidon sirintarae by Kitti Thonglongya
who dedicated this spectacular and beautiful bird
to Princess Sirindhorn Thepratanasuda. Over the
next three years several more specimens were collected
at the same site, but apart from these, and a
fleeting observation in 1978, this remarkable
bird has effectively vanished. An avian enigma,
it has come to epitomise the mythical allure of
rarity to the birdwatcher, and for three decades
it has symbolised the Asian mystery of the ornithological
world. As such it has appeared in logo form in
the pages of this journal as the archetypal little-known
bird. The time has come to compile our knowledge
of the species and to present it afresh in the
hope that it might lead to a dramatic rediscovery.
Paragraph 2 To begin
with, we need to retrace the events of January
and February 1968 and glean what we can from the
available facts. The site of discovery is first
misleadingly given as a big marsh on the Chao
Praya River (1). The type-locality is then specified
as Bung (= Nong = Lake) Boraphet, Amphoe Muang,
Nakhon Sawan Province, central Thailand (1), and
from its subsequent description as a shallow,
marshy, reed-filled lake of 25,000 hectares it
seems clear that this is the big marsh originally
mentioned (a point confirmed by Thonglongya (2)).
Rediscovery efforts in 1980-1981 were apparently
concentrated on an island where all of Kitti's
river martins had been captured (3), suggesting
that, at one time, confidence was high that a
very precise origin was known.
Paragraph 3 This
no longer appears to be the case. The first White-eyed
River-Martins were reportedly caught while night-trapping
roosting swallows (Hirundo rustica, H. daurica,
Riparia riparia), wagtails and warblers by
casting a fishing net over a reedbed (1) a method
repeated by subsequent authors (3,4,5). However,
according to a local technician who worked with
the original field team, the birds were neither
seen in the field nor trapped by any of the team
members, but rather were brought in to the teams
hotel in nearby Nakhon Sawan by villagers following
a broadcast appeal for live wild birds for ringing
purposes (6). It seems likely, therefore, that
the precise site of collection is impossible to
determine, but that it is certainly in the region
of Bung Boraphet, and most likely at the lake
itself.
Paragraph 4 Whatever
their exact origins, nine specimens were initially
collected: one each on 28 and 29 January (although
the label on specimen 53-1218 actually states
27 January 1968 (6)) and seven on 10 February
1968 (1). From analysis of the resultant skins
its closest ally was deemed to be the African
River-Martin Pseudochelidon eurystomina
(1). Initially described as congeneric (1), the
African species and the Asian species differ markedly
in the size of their bills and eyes, suggesting
that they have very different feeding ecologies,
sirintarae probably being able to take
much larger prey and perhaps in different microhabitats
(7). The gape of sirintarae is swollen and hardened,
unlike the softer, fleshier, much less prominent
gape of eurystomina(1,19). The feet and claws
of sirintarae are unusually large and
robust for an aerial feeder (1) and the two species
also have different toe proportions, which might
suggest dissimilar nesting habits (19). These
differences are sufficiently pronounced in the
view of some taxonomists to permit the allocation
of its own genus, Eurochelidon (7), although
other authors support the retention of both species
in Pseudochelidon, arguing that they
mirror patterns in other congeneric hirundines
(8). Whether treated as one genus, or two, the
syringeal structures of the two river-martins
are divergent enough from those of the Hirundininae
to confirm subfamily distinction from the true
swallows, and apparently enough to suggest that
they might belong in a separate family (1,9).
Paragraph 5 Shortly
after these first specimens, a tenth bird was
caught in November 1968 (2) and brought alive
to Bangkok where it was photographed in December
1968 (3). Furthermore, at least two birds (one
pair) reached but soon afterwards died in Dusit
Zoo in Bangkok in early 1971 (3). The only widely
reported field observation was of six individuals
flying low over Bung Boraphet towards dusk on
3 February 1978 (10). In addition, four probable
immature White-eyed River-Martins were reportedly
observed perched in trees on Temple Island in
Bung Boraphet in January 1980 (3,5), and one was
reputedly trapped by local people in 1986 (11).
Both these records remain unconfirmed. Several
subsequent searches have tried to locate the species
around the site. For example, eleven amateur birding
groups surveyed the lake unsuccessfully during
1979 (3). Investigations were carried out between
December 1980 to March 1981 by a team from the
Association for the Conservation of Wildlife but,
despite netting many roosting Barn Swallows in
reedbeds, they failed to reveal any river-martins
(12). In 1988 another concerted effort to relocate
the species was undertaken at Bung Boraphet, ending
with failure as the swallow roosts were highly
disturbed and mobile (13).
Paragraph 6 The
real number of White-eyed River-Martins trapped
in the 1960s and 1970s may have been much higher
than these figures suggest. In the wave of public
and media interest following the sensational discovery
of the species, trappers are rumoured to have
caught around 120 individuals and sold them to
the director of the Nakhon Sawan Fisheries Station
(3,5). Moreover, local markets were reported to
have had several other specimens in January-February
of succeeding years (10). Having been found on
Thai soil and decorated with the name of Thai
royalty, there was a significant local demand
for specimens or caged examples of the species,
for zoos, presentation to dignitaries or as curios
for the affluent.
Paragraph 7 What
has become of the White-eyed River-Martin? Did
this harvest of hirundines extinguish it entirely?
Were these last known individuals merely the doomed
remnants of a population displaced by disturbance
from a specialised breeding habitat? (5) Perhaps.
It is quite conceivably extinct, and if it still
survives its population seems likely to be tiny.
The original series of specimens taken in early
1968 were outnumbered by hordes of trapped Barn
Swallows by a ratio of 9:6,000 (1). In spite of
this exceptional rarity, it was thought that the
species might be regular at Bung Boraphet since
the local bird-catchers had a name for it, nok
ta phong, the swollen-eyed bird (1). Unfortunately,
there has been a drastic decline in the Bung Boraphet
swallow population from hundreds of thousands
reported around 1970 to maximum counts of 8,000
made in the winter of 1980-1981, although it is
not certain if this represents a real decline
or a shift in site in response to persecution
(3). However, an estimated 100,000 swallows were
present at a roost near Chotiravi, near Bung Boraphet,
in August 1986 (11) and there were 30,000 at Bung
Boraphet in May 1988 (11). Nevertheless, a dealer
working the large Chotiravi roost claimed never
to have encountered the species (11). The general
feeling is that an absence of sightings since
early 1980, despite numerous observational efforts,
cast ominous doubts over the survival of the White-eyed
River-Martin (3).
Paragraph 8 Unfortunately,
the habits of swallows around the lake appear
to have altered recently, with very few birds
roosting in the reedbeds until late winter (13).
Much of the population now roosts in sugar cane
plantations, moving back to the reedbeds after
the cane has been harvested (13). The roosts also
form well after dark, whereas they once gathered
before dusk (13). These changes are probably the
result of prolonged disturbance by trappers (11).
In any case, the swallow roosts are more mobile
and difficult to locate, factors that have further
obstructed the rediscovery of the White-eyed River-Martin.
Paragraph 9 The
reduction in Barn Swallow populations in the Bung
Boraphet area is difficult to explain but intensive
trapping activities for the purpose of selling
birds as food in local markets must have played
a major role, as must the annual destruction of
roosting sites to make way for lotus cultivation
(3). Huge areas of reedbed in areas frequented
by roosting swallows were being burnt in February
1986 (11). The hunting of hirundines without a
licence has been illegal since 1972, although
this legislation is rarely enforced (3). Relations
between conservationists and bird trappers at
Bung Boraphet are occasionally fraught, to the
extent that a reserve ranger was killed when trying
to apprehend poachers at roosts in 1987 (13).
Paragraph 10 It
seems that any rediscovery efforts should now
be targeted away from Bung Boraphet, and indeed
perhaps away from Thailand. How might we judge
where best to look? What secrets have hitherto
been disclosed that might help direct our search?
Unhelpfully, the ecology of this bird remains
almost totally unknown, and thus ornithologists
have looked to its presumed relative, the African
River-Martin, to provide clues. Since P. eurystomina
feeds largely over both forest and open grassy
country, nesting colonially in tunnels dug in
sandbars of large rivers (14) it has been inferred
that E. sirintarae possibly does or once did the
same (4). However, the differently shaped toes
might suggest otherwise (19). At least one of
the initial specimens had mud or sand adhering
to its claws, and while this perhaps suggests
a terrestrial perching habit (6), most swallows
occasionally do the same, especially when collecting
nest material. Another clue: in holding cages
used during the swallow ringing programme, the
birds stood quietly in the corner of the cage
in strong contrast to other swallows which move
rapidly from perch to perch calling repeatedly
(1).
Paragraph 11 In
the unconfirmed report of 1980, individuals were
flying after insects with some Barn Swallows and
sometimes perching on the tops of trees (20).
During the 1978 sighting they were apparently
skimming the water surface, possibly to drink
(10). While these accounts describe behaviour
characteristic of most swallows, the only direct
dietary evidence is the fragment of a large beetle
found in the stomach of a specimen (1). This fact,
along with the mandibular morphology of the species,
implies that it consumes sizeable prey.
Paragraph 12 What
about breeding season, distribution and migratory
behaviour? Five of the nine specimens collected
in late January and early February 1968 were immature
(1); they were later termed juvenile, and some
of the other material as subadult (2) (although
this is not mentioned in the original description).
A breeding site within Thailand was initially
considered plausible on the grounds that so many
of the type series were young (2). It has also
been speculated that if nesting occurs in Thailand
it is most likely to do so between March and April,
as this coincides with the local nesting season
for the majority of insectivorous birds, while
the monsoon rains from May onwards presumably
raise water levels above the riverine sandflats
postulated to be the favoured nesting habitat
of the species (5,6,10). It is unlikely, however,
that juvenile plumage would be retained for eight
months, and thus these two facts are difficult
to reconcile. The White-eyed River-Martin has
otherwise been thought a non-breeding visitor
to south-central Thailand (20) and clearly migratory
(4), but these assumptions should also be treated
with care. Although it has only been found between
December and February, and despite the above disparity,
there is insufficient information to rule out
breeding in the Nakhon Sawan area (6,11). In conclusion,
it is unclear whether the species is, or was,
a migrant at all.
Paragraph 13 As
recent searches around Bung Boraphet have been
unsuccessful, let us assume it is a migrant. If
it travelled across Thailand, where did it come
from? The riverine nesting grounds might possibly
lie along one of the four major watercourses (the
Ping, Wang, Yom and Nan) which drain northern
Thailand, either in the immediate vicinity of
Nakhon Sawan or to the north (5,6). If it came
from further afield, perhaps these putative breeding
grounds lie on one of the other major river systems
of South-East Asia, such as the Mekong in China,
Laos or Cambodia, or the Salween and Irrawaddy
in Myanmar (5,6). Evidence that the species breeds,
or has ever occurred, in China is scant, although
a painting by a Chinese artist held in the Sun
Fung Art House of Hong Kong appears to depict
the species (15). This tentative clue has failed
to lead to any further information, and in any
case the subject of the painting is more likely
to be an Oriental Pratincole Glareola maldivarum
(16).
Paragraph 14 A survey
of the Nan, Yom and Wang rivers in northern Thailand
was carried out in May 1969, but was not comprehensive
and relied chiefly on interviewing villagers,
none of whom seemed to know the bird (2). Rivers
near the Chinese border of Laos were searched
in April 1996, local people being shown illustrations
of the species, but without success (W. Robichaud
verbally 1997). Very few other surveys have looked
for it outside Thailand and there is still scope
for research in remote regions where a population
might survive.
Paragraph 15 Throughout
its possible range there is a catalogue of pressures
potentially imposed on the species (5,6). Man
has drastically altered the lowlands of central
and northern Thailand: huge areas are now deforested,
agriculture has intensified, pesticide use is
ubiquitous and urban environments have spread
extensively (5,6). In addition, all major lowland
rivers and their banks suffer a high level of
disturbance by fishermen, hunters, vegetable growers
and sand-dredgers (5,6). Whole communities of
nesting riverine birds have vanished from large
segments of their ranges in South-East Asia owing
to habitat destruction, human persecution and
intense disturbance of most navigable waterways
(5,17,18). Local people routinely trap or shoot
birds for food and for sale in local markets (5,6).
Even at Bung Boraphet Non-Hunting Area (established
in 19793) the trapping of birds has continued,
at some level, up to the present (5,6). If the
species preferentially forages over forest, its
numbers could already have declined to a perilously
low level at the time of its discovery because
of deforestation and the intensification of agriculture
in river valleys (5,6).
Paragraph 16 These
threats are based on the ecological traits inferred
by its suspected taxonomic affinities. It should
be borne in mind that riverine nesting habits
and preferences for forest are only an assumption,
and that it might conceivably utilise some entirely
different habitat. Even the name river-martin
is perhaps a complete misnomer, as the species
has never been seen on a river and is no longer
considered congeneric with the African River-Martin
(7). Interestingly, the most recent scrutiny of
specimens suggested that it was perhaps nocturnal,
or at least highly crepuscular, based principally
on its unusually large eyes (19). This raises
the possibility that it is normally a cave dweller
or a hole-rooster in trees or rock, emerging to
feed in twilight or darkness, and this opens up
new avenues of exploration. There are, for example,
limestone caves not far from Bung Boraphet, and
many more in Laos and southern China.
Paragraph 17 While
there is only a faint chance that this, one of
the most elusive species in the world (15) still
survives, it bears the extraordinary distinction
of being highly unusual in appearance yet overlooked
by naturalists in a well-worked country until
the late 1960s. As it is thus either extremely
rare or inexplicably cryptic, it is not yet time
to give up hope for the swollen-eyed bird. Its
possible range should be revisited with a broader
outlook. The prize, to any successful searcher,
is considerable: solving one of the most puzzling
mysteries of Asian ornithology.
References
1. Thonglongya, Kitti (1968) A
new martin of the genus Pseudochelidon
from Thailand. Thai
National Scientific Papers, Fauna Series no. 1.
Bangkok: Applied Scientific Research
Corporation of Thailand.
2. Thonglongya, Kitti (1969) Report
on an expedition in northern Thailand to look
for breeding
sites of Pseudochelidon sirintarae (21 May to
27 June). Bangkok: Applied Scientific Research
Corporation of Thailand
3. Sophason and Dobias (1984)
The fate of the Princess Bird, or White-eyed River
Martin
(Pseudochelidon sirintarae). Nat.
Hist. Bull. Siam Soc. 32(1):
1-10.
4. Turner and Rose (1989) Swallows
and martins of the world. Bromley, UK: Christopher
Helm.
5. Round, P. D. (1990) Bird of
the month: White-eyed River-Martin. Bangkok
Bird Club Bulletin 7(1):
10-11.
6. BirdLife International (in
press) Threatened birds of Asia.
7. Brooke, R. K. (1972) Generic
limits in old world Apodidae and Hirundinidae.
Bull. Brit. Orn. Cl. 93:
53-57.
8. Zusi, R. L. (1978) Remarks
on the generic allocation of Pseudochelidon
sirintarae. Bull. Brit.
Orn. Cl. 98(1): 13-15.
9. Mayr, E. and Amadon, D. (1951)
A classification of recent birds. Amer.
Mus. Novit. 1496: 1-42.
10. King and Kanwanich (1978)
First wild sighting of the White-eyed River-Martin,
Pseudochelidon sirintarae. Biol.
Cons. 13: 183-185.
11. D. Ogle in litt.
(1986).
12. Anon. (1981) A search for
the White-eyed River Martin, Pseudochelidon
sirintarae, at Bung
Boraphet, central Thailand. Bangkok: Association
for the conservation of Wildlife of Thailand.
Unpublished report.
13. D. Ogle in litt.
(19871988).
14. Keith. S., Urban, E. K. and
Fry, C. H. (1992) The Birds of Africa,
volume 4. London: Academic
Press.
15. Dickinson, E. (1986) Does
the White-eyed River-Martin Pseudochelidon
sirintarae breed in
China? Forktail 2: 95-96.
16. Parkes, K. C. (1987) Letter:
was the Chinese White-eyed River-Martin an Oriental
Pratincole?
Forktail 3: 68-69.
17. Scott, D. A. (ed.) (1989)
A Directory of Asian Wetlands. IUCN,
Gland, Switzerland and
Cambridge, UK.
18. Duckworth, J. W., Salter,
R. E. and Khounboline, K. (compilers) (1999) Wildlife
in Lao PDR:
1999 Status Report. Vientiane: IUCN-The World
Conservation Union/Wildlife Conservation
Society/Centre for Protected Areas and Watershed
Management.
19. P. M. Rasmussen in litt.
(2000).
20.
Ogle, D. (1986) The status and seasonality of
birds in Nakhon Sawan Province, Thailand. Nat.
Hist. Bull. Siam Soc. 34:
115-143. |
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