House sparrows have declined by 71% in Britain since 1977, with the steepest falls in urban areas. Their welfare is affected by lack of nesting sites, reduced invertebrate food for chicks, and loss of seed sources in winter.
House sparrow welfare in declining urban populations is affected by insufficient invertebrate food for growing chicks, nest site loss, and the stress of increasingly isolated small colonies. Chicks fed inadequate invertebrates in their first two weeks develop poorly and may not survive. Urban environments with reduced insect-rich gardens and over-tidy parks cannot support the chick-rearing requirements of sparrows even when adults appear to be doing well. Simple interventions -- leaving garden areas weedy and untidy, installing nest boxes in suitable sites, and reducing pesticide use -- can directly improve sparrow welfare at the household level.