Migratory bird numbers fall in Britain despite last year’s warm spring

British Trust for Ornithology says 2025 breeding season was especially disastrous for warbler species

After a mild, wet and stormy winter in the UK, spring 2025 was one of the warmest and driest ever, while the summer was the hottest since records began, most particularly in England and Wales.

Good news, you might think, for migratory birds – especially for eight species of warblers that travel here from their winter quarters in Africa. Yet according to data from bird ringers, collated by the British Trust for Ornithology (BTO), last year’s breeding season was pretty disastrous.