Despite a warm and dry spring in 2025, migratory bird numbers in Britain have fallen sharply, according to data from bird ringers collated by the British Trust for Ornithology (BTO). The 2025 breeding season proved especially disastrous for several warbler species, with four out of eight species showing significant declines.
Warbler Species Hit Hard
The willow warbler, blackcap, garden warbler, and common whitethroat all experienced notable drops in numbers. Three other species—sedge warbler, reed warbler, and lesser whitethroat—also declined, though less severely. Only the chiffchaff, which winters in North Africa and Iberia and sometimes stays in southern Britain, showed an increase.
Pigeon and Dove Populations Mixed
The BTO's breeding bird survey revealed mixed fortunes for pigeons and doves. While woodpigeon and stock dove numbers continued to rise, collared dove and turtle dove populations continued their rapid decline.
Climate Crisis a Factor
Experts caution against attributing population changes solely to weather, as habitat loss and other factors play a role. However, with the climate crisis causing more extreme weather, vigilance is essential. The BTO emphasizes the critical importance of ongoing monitoring by staff and volunteers.
