The garden warbler is a summer migrant to the UK whose welfare depends on dense scrubby vegetation for nesting and an abundance of invertebrates for feeding during the breeding season.
The welfare of garden warblers depends on maintaining the structural diversity of British countryside, particularly the dense scrubby habitats that intensive agriculture has steadily eroded. Individual birds require sufficient invertebrate prey to sustain themselves and their chicks through the breeding season, making insecticide-heavy farming practices directly harmful. On migration, birds face exhaustion, dehydration, and predation. Maintaining UK scrub habitats ensures returning birds can establish territories and breed successfully.