Flight more direct, often higher, than native sparrows. Bill thick, conical; legs short; stocky build. One molt per year, but seasonal variation pronounced. Adult male: worn (breeding) male ...

Poland’s sparrow population has declined by more than 20%, shedding around 1.5 million breeding pairs in the last ten years.

You've probably heard of invasive plants, but what about invasive birds? These common nonnative species are now abundant in ...