Sometimes even familiar birds can fool you. This is a picture taken just outside my house a month ago. I suspect most birdwatchers would do a double-take when they see this bird for the first time. The beak is just not right. After struggling with it for a day, I figured out that it was just an immature northern mockingbird with a funny overgrown bill, and confirmed it with an expert. They are usually shorter with a slight downwards curve (see, for example, the Wikipedia picture ).
It also made me ponder whether one is more likely to see variations among the very young of a species. Mutations that are not well-suited to their lifestyle or the environment are likely to result in earlier deaths, making significant mutations as a whole less likely to be observed in grown-up birds.
