Tree sparrows are on the British Trust for Ornithology's red list for species which have seen a drop of 50% or more in their UK breeding population.

The tree sparrow is on the red list of species of Birds ... Although there have been signs of recovery in the UK, with numbers starting to rise since 1994, the current population estimate for ...

At that season it is frequently mistaken for the chipping sparrow, but the 2 rarely overlap in winter. The American tree sparrow often occurs in flocks of up to 50 birds. In habitat and behavior ...