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Chinese Crested Tern Thalasseus
bernsteini
The Chinese Crested Tern Thalasseus bernsteini is one
of the world’s rarest birds with the entire population
reported to be fewer than 50 birds.
Little is known
about this species and only a few sightings have been reported
(Dickinson and Eck 1984, del Hoya et al. 1996, Liang et al.
2000, Candido 2006).
For most of the
20th century, it was thought extinct – confirmed
sightings in the wild ceased in 1937. But a chance discovery
in the year 2000 in the Matsu Islands was made by film maker
Liang Chieh-de (Liang et al. 2000). A few terns have been seen
in the Matsu Islands since 2000 with the greatest single day
count of 12 birds. The
non-breeding range of this rare tern includes southern China,
Indonesia, Malaysia, Thailand and the Philippines (Mees 1975,
Harrison 1983, Dickinson and Eck 1984, Del Hoyo et al. 1996,
Liang et al. 2000,
Collar 2003). The only known breeding site is the Matsu Islands, in the Republic of
Taiwan (25˚56’N, 119˚51-120˚01E). Sightings have been reported from as far
north as the Huang Ho Estuary (
Easton no date). It is now possible to join
birdwatching tours to see the species in the
Matsu Islands.
References
Candido, E. P.
M. 2006. Chinese Crested Tern: observations on juveniles in
the Matsu Archipelago of Taiwan. BirdingASIA 6: 34-35.
del Hoyo, J.,
A. Elliott, and J. Sargatal 1996. Handbook of Birds of the
World. Vol. 3. Hoatzin to Auks. Lynx Edicions,
Barcelona.
Collar, N. J.
2003. A third Philippine specimen of Chinese Crested-tern
Sterna bernsteini
Forktail (Journal of Oriental Ornithology) 19: 151.
Dickinson, E.
C. and Eck, S. 1984. Notes on Philippine birds, 2: A second
Philippine record of Sterna bernsteini. Bulletin.of the
British Ornithological Club 104: 72.
Harrison, P. 1983. Seabirds: an identification guide. Houghton
Mifflin, Boston.
Liang, Chieh-te.
2001. The mythical bird; the Chinese Crested Tern. Council of
Agriculture, Lienchiang
County Agricultural
Improvement Field, Taiwan. DVD
Liang, C.T.,
S.-H. Chang, and W-h. Fang. 2000. Little known Oriental bird:
Discovery of a breeding colony of Chinese Crested Tern.
Oriental Bird Club Bull. 32: 18-20.
Mees, G. F. 1975. Identiteit en status van Sterna
bernsteini Schlegel.
Ardea
63: 78-86.
Chinese Crested Tern
Distribution Map
Chinese Crested Tern Behaviour
Very little is
known about the behaviour of this species. Adults carry small
fish in their bills to nesting islands and feed them to their
chicks. These fish were likely caught in the estuaries of the
Min and Lien rivers or in the shallow waters around the
island. Typical of terns, the flight is strong and direct.
Nothing is known about the displays of this species.
Thousands of
nesting seabirds nest in the
National Matzu
Nature Reserve for Terns.
The tern nesting islands are rocky outcrops that form part of
the much larger Matsu Island archipelago. Chinese
Crested Terns nest with other species of terns
including the
Great Crested Tern (Sterna bergii), Roseate Tern (S.
dougallii), Bridled Tern (S. anaethetus), Black-naped
Tern (S. sumatrana), and Black-tailed Gull (Larus
crassirostris).
Single chicks
have been seen with parents leading to the assumption the
clutch size is a single egg but this is not confirmed. The
egg(s) are laid on the ground in a shallow depression. The
incubation period is not known but is probably about three
weeks long. Some nesting behaviour of this species was
documented on DVD by Liang (2001).
Chinese Crested Tern Science
It is puzzling
that this species is so rare when several other species that
nest on the same islands in the Matsu Archipelago appear to be
thriving. There is an urgent need to learn more about the
ecology of this species so that conservation efforts can be
directed at possible causes for its scarcity. In particular,
we need to know the causes of nesting failures. We also need
to know where the species resides in the non-breeding season.
Chinese Crested Tern Conservation
The Chinese
Crested Tern is designated as
Critically Endangered by the IUCN Red Data Book because of
very small numbers of birds and possibly loss of eggs. Liang
(2001) showed that eggs of several species of terns including
the Chinese Crested Tern were often taken by fishermen. The
Taiwanese Coast Guard has been intercepting and informing
fishermen that the practice is disallowed with some success.
The conservation of this rare tern will require information on
its distribution and population size so that efforts can be
focused where it most needed.
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