Cheryl Cronnie asks if this is a house sparrow (Passer domesticus) or a tree sparrow (Passer montanus) that she has photographed in the reserve.

House sparrows are sexually dimorphic, which means that the males and females have different plumages. The male’s most distinctive feature is his bright chestnut coloured head, topped with a grey cap, whereas the female is camouflaged all over in grey and brown freckles. Tree sparrow males and females look exactly the same, very like a male house sparrow but without the grey cap.

Cheryl’s sparrows (images 1&2) are house sparrows; the male is wearing a grey cap and the female is in camouflage.

Header image by Cheryl Cronnie

[1]&[2] house sparrow [3]&[4] tree sparrows

Their common names reflect their differing habitats. House sparrows, opportunist feeders that are happy to scavenge in back yards and gutters, are more commonly found close to human habitation, nesting under house eaves and in roof spaces. Tree sparrows eat seeds and insects and stick to farmland hedges and edges for their nest sites.

Both species were very common in the past but have suffered significant declines since 1970. Tree sparrows have suffered a horrifying 93% decline; house sparrows, not doing much better, have declined more than 70% in the same time. Both are recent additions to the UK Red List of Birds of Conservation Concern. The latest data suggests that numbers of both species may have stabilised at a breeding population of house sparrows of 5,300,000 pairs and of tree sparrows at 200,000 pairs.

So far, we do not have the tree sparrow on the reserve’s species lists. Keep an eye out for a small brown bird with a chestnut head (no grey stripe!) and a black bib.