Migratory bird numbers fall in UK despite warm spring 2025

Migratory bird populations in Britain declined during the 2025 breeding season despite one of the warmest and driest springs on record and a summer that was the hottest since measurements began, particularly in England and Wales, according to data from the British Trust for Ornithology (BTO).

The BTO’s bird ringing data showed that out of eight warbler species that migrate from Africa, four — willow warbler, blackcap, garden warbler and common whitethroat — experienced significant population falls. Three others, sedge warbler, reed warbler and lesser whitethroat, also declined but at a less severe rate. Only the chiffchaff, which winters in north Africa and Iberia or stays in southern Britain, recorded an increase.

The BTO’s separate breeding bird survey revealed mixed trends among pigeons and doves. While woodpigeon and stock dove numbers continued to rise, the two smaller species, collared dove and turtle dove, maintained their rapid decline.

Researchers caution against attributing these population changes solely to the weather conditions of a single year, noting that many other factors, including habitat loss both in Britain and in the birds’ wintering grounds, may play a role. However, with the climate crisis causing more extreme weather events, vigilance remains essential.

The findings underscore the critical importance of ongoing monitoring by BTO staff and volunteers to track and respond to these trends, the organization said.