[CT Birds] White-tailed Kite ageing and sexing

julian hough jrhough1 at snet.net
Mon Aug 2 12:56:41 EDT 2010

For those that are interested, based on the literature and field observation, 
the kite is a 2nd cal-year (“first-summer”) aged as such particularly by the 
retained two outermost juvenile primaries which are worn and brown. Unlike 
falcons, White-tailed Kites replace most of their juvenile plumage via a body 
moult in the first fall of life but retain the juvenile primaries and tail (this 
moult is only partial). Between January and June, inner primaries and central 
tail feathers are replaced and another body moult occurs at the same time. The 
secondaries are also replaced subsequently and the outer sets of tail feathers 
too. This fits perfectly with the Stratford bird which has new, fresh adult-like 
body feathers, retained outer primaries and is growing in new secondaries and 
tail feathers – it  is thus currently undergoing its first complete moult.

Due to the variation in size, although the bird appeared to be largeish, without 
comparison it may be unwise to assign a sex to this individual.

Since it is in active moult it may hang around for a while since moult requires 
energy to complete. I never saw the bird catch prey during the day so it may 
move on if it doesn’t find anything to eat. We shall see.

As others have mentioned, Dennis Varza is to be congratulated on a superb find 
and we appreciate him getting the word out as quick as he could to allow many, 
many birders a fantastic day out in CT!! And to Scott for his wardening of the 

Julian Hough,
New Haven, CT

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