Barn swallows are iconic farmland and wetland birds whose populations are declining across much of Europe. Their welfare depends on a complex interplay of factors spanning three continents.
Barn swallow welfare is directly linked to aerial insect abundance, which has declined dramatically due to agricultural intensification, pesticide use, and habitat loss. Insect scarcity forces adults to fly further for food and reduces chick nutrition. Cold, wet summers cause mass chick starvation when insects are unavailable. Climate change is affecting both breeding season insect availability and conditions on African wintering grounds. Farm-level changes to increase insect abundance - including wildflower strips and reduced pesticide use - have measurable benefits.