House sparrows have disappeared from many UK city centres since the 1990s, with welfare implications from loss of food, nesting sites and social flock opportunities.
House sparrows are gregarious birds that form tightly bonded social groups. Small, isolated urban populations face both demographic collapse and welfare harms from reduced social opportunity and inadequate food. Supplementary feeding of the right food at the right time — particularly live or dried mealworms during the breeding season — demonstrably improves reproductive success. Sparrow terrace nest boxes mounted on walls provide multiple adjacent nest cavities that suit their colonial nature.