The Cooper’s hawk I wrote about last week was a bit of an anomaly for me.

It’s not that I don’t see Cooper’s hawks often, but I typically see immature Cooper’s hawks. The one featured last week was an adult. Looking back through my photo collection, the vast majority of Cooper’s hawks I have photographed were immature birds.

With many birds, differentiating young birds from adults can be tricky as the time period between immature plumage and adult plumage is relatively short. With Cooper’s hawks, it’s easier as they retain their immature plumage into their second year. Bald eagles, similarly, do not obtain their classic white heads and tails until they are four or five years old.

As immature birds, Cooper’s hawks (as well as closely related sharp-shinned hawks) are brown with tan-streaked white chests and bellies. As adults, they are blue-gray with reddish-streaked white chests and bellies. Immature Cooper’s hawks have yellow eyes, and adults have red eyes. Interestingly, ospreys are the opposite with adults having yellow eyes and immatures having orange-red eyes.