One of the most sedentary bird species, a typical sparrow rarely moves more than a kilometre or two. However, some young birds move further away before joining a breeding colony.

They routinely congregate in large, loose groups, flying with urgency from bush to bush, or engaging in communal bathing. They will nest as close as 0.3m from another pair in extensive colonies. Out of the breeding season they roost together, sometimes as many as 100 birds: as dusk starts to fall large groups can be heard chattering noisily in the depths of a thick bush. Early to bed, they seem to be late risers too, waiting for the sun to rise before making their presence known.

Although seed eaters (particularly grasses and low shrubs), they feed their young invertebrates while in the nest and can be seen picking aphids and other insects from growing vegetables. Some also seem to enjoy spinach leaves and maybe those of other vegetables too.

Why have their numbers declined? Surely the loss of weed seeds has contributed both in the wider countryside and in manicured gardens. Also, the massive decline in insect populations may mean the young starve. Other factors may be loss of nest sites, especially where houses have “anti-vermin” guards installed when re-roofed. Removing dense shrubbery from gardens and parks, in which sparrows may hang out, takes away roosting sites and daytime shelter from predators.

It is now thought that on top of such factors, house sparrows have suffered an epidemic of avian malaria; there are indications, however, that the population has stabilised and possibly and numbers are increasing from recent lows.