Date: 2/11/18 12:02 pm From: Michael J Mefford <mjm...> Subject: [obol] Re: Signs of Spring
Maurice A Jenkins,
I never bother even attempting making bald eagle sex. Plumage is no help. Females are slightly larger. However, only when a pair are perched side-by-side have I noticed the female's slightly larger neck girth (same with gulls) and the only trait I've ever been able to pick out, and even then it can be questionable.
Peregrine falcon males are known as "tierce", meaning the male is a third smaller than the female. That's a huge difference in size, but it is surprisingly difficult to make the sex of nestlings, even though they are side by side for comparison, and even when full grown ready to fledge. In the air, however, a male peregrine's faster wing beat (because of shorter wings) is an easy clue.