Bats and swifts are both aerial insectivores that depend entirely on flying insects for food. Both groups have experienced significant population declines linked in large part to the collapse of aerial insect populations across Britain. Understanding and supporting the insect-rich habitats these animals depend on is foundational to their conservation.
The Aerial Insect Crisis
Aerial insect biomass has declined by an estimated 50-80% in parts of Europe since the 1970s, driven by agricultural intensification, pesticide use, light pollution, and habitat loss. This decline has cascading effects on aerial insectivores: swifts, swallows, martins, and all bat species are food-limited in many areas. Population declines in these groups are therefore linked to a broader ecological crisis.
Key Foraging Habitats
Traditional hay meadows and permanent pasture: Rich in invertebrates through varied sward structure, diverse plant communities, and absence of pesticides. Critical foraging habitat for many bat species and hirundines.
Woodland edge and rides: Sheltered corridors of insect activity used by many bat species including lesser horseshoes, barbastelles, and Bechstein's bats.
Watercourses and wetlands: Rivers, ponds, and wetlands generate high densities of flying invertebrates (midges, mayflies, caddisflies) and are particularly important for Daubenton's bats and some hirundines.
Urban green spaces: Parks, gardens, and urban trees provide foraging habitat for common pipistrelle and soprano pipistrelle bats, swifts, and house martins in urban areas.
What Landowners and Gardeners Can Do
Reduce or eliminate pesticide use — particularly insecticides that directly kill flying invertebrates
Create or restore wildflower areas (meadow grassland) that support diverse invertebrate communities
Maintain hedgerows and mature trees as bat roosting sites and foraging corridors
Reduce garden and security lighting — light pollution disrupts bat activity patterns and kills night-flying insects
Maintain water features — even small garden ponds support invertebrate diversity