Male Kestrels

posted by Jerry Liguori at
on Tuesday, October 8, 2013 

Let me touch on a subject that has been published already and I think is fairly well-known. Juvenile male Kestrels molt their body feathers in their first fall (often on migration). This is unlike other raptors, making them tricky to age in flight. To start, juveniles have whitish chests with black streaks, but can be seen in different stages of body molt until they acquire a complete adult orange breast by late fall. Some birds molt quicker than others, as is true for all raptors. Often, it is possible for bird banders to age male Kestrels during fall migration, but toward the end of fall, it can be difficult. And, of course, and Kestrel molting flight feathers in fall is an adult. Also, bird banders can look to see if fault bars are present in the wings or tail, but this is impossible to see in flight.

Check out these photos below ("click" to enlarge) and see if you can age them...

Blogger Ron Dudley said...

Nope, I can't age them, at least not with any confidence. But I'll be hanging around to see what others might have to say...

October 9, 2013 at 3:50 AM  
Blogger Jerry Liguori said...

Oh, I realize my wording sounds like a quiz, didnt mean for that. Just meant to show juveniles in different stages of fall molt but photographed around the same time. Only one bird is an adult shown for comparison...7th bird down.

Needed a camera sensor cleaning on some of these!

October 9, 2013 at 6:18 AM  
Blogger Bryce said...

The 7th bird down is an adult because it lacks any streaking on the breast? This is good stuff by the way. Glad you are revisiting it.

October 9, 2013 at 11:35 AM  
Blogger Jerry Liguori said...

Yes Bryce, although its tough to see the left over streaking on 5, 6, and 8.

October 9, 2013 at 3:32 PM  
Anonymous Cingez said...

Interesting, something I knew about but really didn't know if you get what I mean. Nice to see these examples.

October 10, 2013 at 9:27 AM  

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