House sparrows (Passer domesticus) and tree sparrows (P. montanus) visit my garden. I'm not particularly proud of having a yard full of introduced species but it is interesting to see them side by side. Photographing them is proving difficult because they're very jumpy. Once they spot any movement, they're off. The low light on this overcast day hasn't helped, either. But I did manage to get this passable shot of a tree sparrow before the flock made its getaway.
The two species are easy to tell apart. The males of both species have an inky bib, but the male tree sparrow sports a chestnut cap and a black patch on each cheek, whereas the house sparrow has a grey cap and no cheek patches. Male and female tree sparrows are similar. (Presumably they can tell each other apart.) Female house sparrows are less flamboyant than the males, lacking both bib and cap.