The U.S. Fish and Wildlife Service (USFWS) Southwest Region Migratory Birds Program, the USFWS National Raptor Program, and private citizen Tig Tillinghast have released a new publication to help with accurate age estimates for nestling raptors. 

A Photographic Guide For Aging Nestling Cooper’s Hawks has been produced to aid biologists, wildlife rehabilitators, and bird watchers in accurately aging raptor chicks. The guide includes dozens of photographs and descriptions of hatch through fledging to illustrate developmental changes in nestling Cooper’s hawks. It also include a section depicting plumage and eye color changes in adults to assist readers in estimating age beyond fledging.