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Wallace's Hawk-Eagle, adult or young adult? Sarawak, Malaysian Borneo (1 Viewer)


Well-known member
Location: Lowland forest, Sarawak, Malaysian Borneo
Date: Nov-2022

Is it possible to tell if this individual is adult or could be young adult? I also made a comparison with another confirmed adult female (nesting nearby with over 30 days old chick), sighted at close proximity area (about 2-3km radius from nest) but not same time and day. If it is young adult, that means there were second family nearby.

My initial thought it could be young adult based on its slow low level flying pattern and lighter plumage. But after I put side by side comparison with adult female, I'm not so sure now.

This individual were flying pretty low. Unsure if this is young adult or is same nesting adult female I'm observing.

PIC-20221125-094618-DSC00167-A7R3.JPG PIC-20221125-094635-DSC00175-A7R3.JPG PIC-20221125-094648-DSC00180-A7R3.JPG

Comparing to confirmed nesting adult female which extracted screenshot from various video footages from other days. Picture boxed within blue color are confirmed adult female.

resize_collage1.jpg resize_collage2.jpg

Same individual nesting adult female boxed in blue color above.
resize_vlcsnap-2022-11-29-12h49m00s157.jpg resize_vlcsnap-2022-11-29-12h51m05s581.jpg resize_vlcsnap-2022-11-29-12h52m29s521.jpg

Appreciated for any help. Thanks.
The tail is post-juvenile, there are secondaries of different age but not apparent juvenile feathers left (but spread wings may still reveal interesting details). Body plumage is quite pale and warm brown, but Bornean adults are often just like this (darker and more contrasting in the Peninsula). It is an adult and I do not see any reasons to call it younger bird. However, plumage development and moult of these birds is not very well known. I do not know of any differences in the plumage between the sexes, but females are distinctly larger.
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