Supplementary feeding of mealworms enhances reproductive success in garden nesting House Sparrows Passer domesticus

Capsule Mealworm provisioning increased clutch size and chick survival in garden-nesting House Sparrows. Aim We tested experimentally whether invertebrate availability limits reproductive success in garden-nesting House Sparrows Passer domesticus. Methods Mealworms were provided in feeders as supplementary food for House Sparrows nesting in suburban and rural domestic gardens. Surveys of provisioning adult sparrows were used to determine mealworm usage and nest outcomes were monitored. Results Provisioning parent sparrows travelled up to 165 m from nests to collect mealworms, but most usage of supplementary food was confined to nests within 30 m of feeders. Mealworm provisioning increased clutch size and chick survival which together increased fledgling production by 55%. Conclusions Management interventions that increase the availability of invertebrate prey for garden-nesting House Sparrows have the potential to stimulate substantial increases in reproductive success.