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CHINESE
CRESTED TERN
Sterna bernsteini
a brief history
by Andrew Easton
The Chinese Crested Tern has always been rare and little known; further confusion was caused by it being independently described and named twice, first as Sterna bernsteni by Schlegel in 1863, and then S. zimmermanni by Reichenow in 1903.
Photo by Chang Show-Hwa
Reproduced with permission of the Wild Bird Federation Taiwan http://bird.org.tw/
Its breeding
grounds had never been discovered, but in 1937, 21 were killed for specimens
on islands near Qingdao (Tsingtao) on the Shandong Peninsula in north east
China. Some of these were reported to be in breeding condition, so it has
always been assumed that this was a breeding area.
There were some old winter records from the south east coast of China near
Fuzhou (Foochow) in Fujian province, and neighbouring Guangdong province;
south Thailand; north west Borneo; Halmahera and the Phillipines.
After
the 1937 massacre (I can think of no more appropriate word for it) the species
was not recorded again until June 1980 when 10 were seen near Libong in south
Thailand, and three probable ones were seen in the Huang Ho delta in September
1991, just to the north of the presumed breeding range.
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Dark blue represents
the known wintering areas. No doubt the true distribution will prove to be much more extensive when the identification features for this species are properly sorted out. |
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The immature plumages and eggs are undescribed, hardly surprising, as killing all the birds that turn up to breed and putting them into draws in museums does tend to inhibit reproductive success.. Similarly its diet and behaviour are completely unknown.
Then in the summer of 2000 quite out of the blue came news that four pairs, with four young between them, had been discovered breeding on an island just off the coast of Fuzhou in China, but administered by Taiwan. This is a long way to the south of the earlier records, but where it has previously been recorded in winter, whether this indicates it to be resident in that area, or just that it returns early to the nesting sites remains to be seen. Provided they are given a chance. Fortunately the island is already a nature reserve so there is a degree of protection here, but egg poaching for food is quoted as a problem in the area.
Article from the Hong Kong iMail newspaper 8th August 2000
Click here to view BBC News website article - this link will open in a new browser window
The photograph
released to the press taken by the discoverer, Liang Chieh-teh, shows two
adults with one small chick, nesting next to pairs of Crested Terns
S. bergii. The most striking feature is the very extensive white fore
crowns of the Chinese Crested Terns, this came as quite a surprise as all
illustrations of summer plumaged adults were depicted with full black crowns.
The photographs were taken in mid summer in June, so would be expected to
show typical summer plumage. So not only are its behaviour, nesting details,
and immature plumages unknown, but the seasonal variation in the plumages
of the adult birds is now thrown into some confusion.
It seems quite probable that some Chinese Crested Terns viewed distantly,
when the black tip to the bill would not necessarily be discernible, but which
had a white fore crown, may have been passed over as Crested Tern. So much
for the collecting of specimens helping the identification process.
Observation
of the living birds should reveal the true plumage patterns of the species
far more reliably than individual corpses frozen at a moment in time ever
can.
REFERENCES:
del
Hoyo, J., Elliot, A., & Sargatal, J. eds (1996) Handbook
of the Birds of the World. Vol. 3. Hoatzins to Auks. Lynx Edicions, Barcelona.
King, Warren B. compiler (1981) Endangered Birds of the World, The
ICBP Red Data Book. Smithsonian Institution Press, Washington, D.C.