[CT Birds] White-tailed Kite ageing and sexing
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
New Haven, CT
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