查看完整版本: Sexing Roseate Tern? 如何分辨粉紅燕鷗的性別？

Sexing Roseate Tern? 如何分辨粉紅燕鷗的性別？

I have read from the book "Terns of Europe and North America, by Klaus Malling Olsne and Hans Larsson" that measurement of [u]tail fork [/u]are different on male and female of Roseate Tern.  The actual numbers for birds in the Caribbean (race [i]dougallii[/i]) are:

Adult male: 80-136 mm, n=50
Adult female: 65-119 mm, n=29
Juvenile: 35-70 mm, n=11

Here is some photo taken in HK (presumably race [i]gracilis[/i] from Australia).
A short-tail adult (likely female)
[attach]1937[/attach]

A long-tailed adult (likely male)
[attach]1938[/attach]

Another long-tailed adult
[attach]1939[/attach]

Photo are taken on 19 July 2008 at Tap Mun.
Thank to a member for pointing out the typing mistakes.

HF Cheung

[[i] Last edited by HFCheung at 13/08/2008 22:36 [/i]]

爸爸來自澳洲？ So papa is from Australia? 3551em43445

（攝於 Taken on 27/7/08 [url=http://www.hkbws.org.hk/BBS/viewthread.php?tid=5571&extra=page%3D1]刧後餘生 The last Surviving Family in southern waters[/url] ）

[IMG]http://i89.photobucket.com/albums/k232/HKBWA/Terns/080727DSC_8627RSatPP.jpg[/IMG]

[IMG]http://i89.photobucket.com/albums/k232/HKBWA/Terns/080727DSC_8775RSfamily.jpg[/IMG]

不過這對的尾羽長度卻差不多。
But the different is not that big in this pair

21/6/08 南部水域 Southern Waters

[IMG]http://i89.photobucket.com/albums/k232/HKBWA/Terns/080621DSC_6088RSmating.jpg[/IMG]

Another pair is true with the assumption.
[url=http://www.hkbws.org.hk/BBS/viewthread.php?tid=5441&extra=page%3D1]http://www.hkbws.org.hk/BBS/viewthread.php?tid=5441&extra=page%3D1[/url]

Gary