The house sparrow was once the quintessential British urban bird, but populations have declined dramatically in cities where food, nesting sites, and invertebrate chick food have been lost.
House sparrow decline in cities is a welfare crisis for individual birds and a biodiversity signal of urban ecological impoverishment. Chick starvation due to invertebrate scarcity is a particularly significant welfare impact - nestlings that die from insufficient food experience prolonged hunger and weakness. The interventions that would most help urban sparrows - reducing pesticide use, increasing insect-friendly planting, and retaining nesting sites in buildings - are achievable at household and community scales. Urban wildlife gardening that prioritises invertebrate abundance would benefit house sparrows and dozens of other insectivorous species.