In the fall, brown-plumaged NOHAs can be aged by eye color...ad females have yellow eyes just as the gray-plumaged ad males, while brown-eyed birds in brown plumage are imm males and females. I do not know when the color transition from brown to yellow takes place, so it may or may not be applicable now.
This color transition is the exact opposite of what occurs in buteos like Red-tails and Rough-legs where imm are yellow and ad brown. I've had Red-tails in hand whose age I knew by wing molt pattern that were 2 to 3+ years old yet still retained some yellow in the eye, sometimes quite noticeably yellow.
From: Hector Galbraith <[log in to unmask]>
To: VTBIRD <[log in to unmask]>
Sent: Wed, Mar 28, 2012 12:50 pm
Subject: [VTBIRD] oops harriers
My last posting should have stated that "I do not know if females and
immatures are separable".
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