Male ducks don’t look anything like female ducks, at least during the breeding season. And you can easily tell the boy Black-headed Grosbeaks (right) from the girls (below)… in fact, they don’t look like they even belong to the same species! But with lots of birds, from Steller’s Jays to Canada Geese, it seems that only they know who is who.
I’ve often wondered just how they do that. What is it that tells male Red-tailed Hawks who the ladies are? How do California Gulls avoid courting a gull of the same sex? Well, I just read some fascinating articles that solved this mystery, at least when it comes to Black-capped Chickadees.