These are simply the feathers attached to the thumb. The join is
on the wrist (or carpal joint) - obviously. Certainly not the elbow. Easiest seen
on chicken wings (either cooked or not yet cooked). Presumably on all birds.
Not all birds can be seen extending the thumb outwards though.
Philip
From: Birding-Aus
[ On Behalf Of Chris Shaw
Sent: Sunday, 30 October, 2022 1:35 PM
To: Birding Aus
Subject: [Birding-Aus] Bastard Winglets on a Nankeen Kestrel
Alula
flight feathers or, bastard winglets are small wings at the elbow of birds
especially raptors... and probably many others. I took some photographs of a
Nankeen Kestrel displaying them in strong up-draughts hovering above the cliffs
south of my home in Adelaide... and an Australasian Pelican sans alula's...
...
can be seen on my blog above…
+61 409 675912
https://www.ararelitus.com
After the game, the King and the Pawn go into the same box. -
Italian proverb