The bird displays an even split down the middle between male and female feather coloring, leaving researchers to label it a “unicorn.” ...

How many female birds can you find in a day? Can you tell males from female birds? Some are easy, some are tricky, some are nearly impossible.

Female European robins (Erithacus rubecula) sing throughout autumn and winter – and their songs are just as physically and mentally challenging as those of males.

In a robin couple, a male brings his female partner nesting material as she constructs the robins’ nest. The female builds the cup-like nest with mud as its foundation and lines it with grasses ...