Subject: [Frigatebirds] Great Frigatebird 黑腹軍艦鳥 [Print This Page] Author: wleepoin Time: 27/04/2008 18:11 Subject: Great Frigatebird 黑腹軍艦鳥
Po Toi Outing today (27Apr08)
South-West Water of Lamma Island
Thanks for Paul & all the experienced birders who found & help to ID this lovely bird!
Amazing!!
PWMK Author: hpippen Time: 27/04/2008 18:22
Thank you so much for Paul & all the experts who found & help to ID this dream bird of me. ops:
and Thanks to PWMK for leading the wonderful trip!
Author: sammysam Time: 27/04/2008 19:23
What's a wonderful trip! Thanks to all experts and HKBWS! Author: cchristina Time: 27/04/2008 19:48
Thanks to Great Frigatebird for showing up and let us got a wonderful tick!
Thanks Paul, Mike and all bird experts for finding this amazing bird. Thanks Peter and Michelle for your leading the trip!
Author: lmichael Time: 27/04/2008 21:23
Thank you Christina for such great photos. Really useful. A great tick for us all!
Mike Leven Author: lmichael Time: 27/04/2008 21:25
I didn't check properly who posted....thank you ALL photographers for great work.
Mike L Author: kmatthew Time: 27/04/2008 21:53
:shock: Wow!! What a great bird to see!! Great photos to all photographers!! Author: cthomas Time: 27/04/2008 22:17
Thanks for all experts lead me to see this great bird!
27/4/2008
Southern Water of HK 香港南區水域
Leica 800mm + 20D
ISO200 f7.1 1/640s Author: cmichaell Time: 28/04/2008 22:45 Subject: Great Frigatebird
Congratulations to all photographers for a great set of pics, and to Paul for finding this bird at long range in the mist. Identifying juvenile frigatebirds is not easy, but these photos clearly confirm the field identification as Great Frigatebird.
By its much larger size and wingspan compared with the two nearby Black Kites, it could be seen from far off that this was one of the larger species [ie Christmas Island or Great], and not the smaller Lesser Frigatebird which is nearer to Black Kite in size. Seen closer the bill was also too long for Lesser. Christmas Island has the longest bill on average followed by Great. However there is a large overlap which is further complicated by females of each species being bigger than their respective males. Thus a female Great is similar to a male Christmas Island.
The main feature seperating juvenile Great from Christmas Island is the shape and extent of the white underparts. From directly underneath, the shape appeared classic for typical Great with a curved [convex] boundary with the dark breast band, tapering sides which narrowed towards the rear, and a rounded or square-cut [not pointed] cut-off across the lower belly in front of the feet and ventral area. The clincher is the absence of prominent solid white axillary spurs extending out from the sides of the middle of the white underparts onto the axillaries and leading forward onto the underwing area, which is a diagnostic feature of Christmas Island.
However, when viewed from the side, the shape of the white underparts can be seen to be more complex and variable. On the right side there is a clear short white spur extending out across the upper flanks, but not across the axillaries onto the underwing. Curiously, this is assymetric and not matched by a similar strong feature on the left. The spur is accentuated by the dark rear flanks cutting in behind. Individual Great Frigatebirds can show short spurs or even extended scalloping across the underwing, and the pattern on the HK bird is within the range observed for Great and not Christmas Island.
A final point is that the alar bars [the pale diagonal areas across the inner upperwings] appear buffish and not whitish. All juveniles have prominent alar bars, but Christmas Island has the most marked which often appear whitish after bleaching and wear. The less prominent alar bars on the HK bird further reinforce its identity as Great.
It is interesting to note that the date fell within the same period [14 April to 20 May] as the three previous accepted records.
Mike Chalmers Author: hpippen Time: 29/04/2008 01:08
Thanks for the details! Mike
Here is a record shoot for the size comparison.
Please note that the Black Kite was much closer to us.
Pippen
Author: cywong Time: 30/04/2008 19:02
Thanks to Michelle and Peter for leading the trip and all the bird experts for finding the seabirds. It's a wonderful trip!
Author: DCW Time: 21/04/2011 22:18
Welcome to HKBWS Forum 香港觀鳥會討論區 (http://hkbws.org.hk/BBS/)
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