Date: 2/22/21 6:36 am From: Cliff and Lisa Weisse <CliffandLisa...> Subject: Re: [inland-NW-birders] Finches.
On 2/22/21 2:29 AM, Ron Louderback wrote: > The bill of a Purple Finch is shorter and slightly curved. A Cassins’ is sharply triangular and larger
Some Cassin's have really long bills but the main difference is is shape. Cassin's reliably has a straight culmen with slight droop at the tip while Purple has a more evenly curving culmen. This is usually pretty easy to observe in the field but beware of bill shape in photos. It's hard to judge angles correctly and I've seen the same individual appear to have both straight and curved culmen in a series of photos. My two cents' worth.
-- Cliff and Lisa Weisse Island Park, Idaho <cliffandlisa...>