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

Despite one of the warmest and driest springs on record in the UK during 2025, numbers of several migratory bird species, particularly warblers, have declined significantly. Data from the British Trust for Ornithology (BTO), collected through bird ringing and breeding bird surveys, revealed that four warbler species—willow warbler, blackcap, garden warbler, and common whitethroat—experienced notable population decreases. Three additional species—sedge warbler, reed warbler, and lesser whitethroat—also saw declines, though less severe. The chiffchaff was the only warbler species to show an increase, likely due to its wintering grounds being closer to the UK. The BTO’s breeding bird survey also highlighted mixed trends among pigeons and doves. While larger species such as the woodpigeon and stock dove continued to increase in number, smaller species like the collared and turtle doves are facing rapid declines. These contrasting patterns underscore the complexity of factors influencing bird populations beyond immediate weather conditions. Habitat loss, both in the UK and in the birds’ wintering areas, remains a significant threat. Experts caution against attributing population changes solely to weather variations, emphasizing the multifaceted challenges migratory birds face amid the ongoing climate crisis. The increasing frequency of extreme weather events may exacerbate these pressures, making continuous monitoring essential. The BTO’s work, supported by dedicated staff and volunteers, plays a vital role in tracking these trends and informing conservation efforts aimed at protecting vulnerable species. The decline in migratory birds, despite favorable weather conditions during the breeding season, highlights the urgent need for comprehensive conservation strategies that address habitat preservation and climate resilience. These findings contribute to a broader understanding of the challenges facing UK wildlife and the importance of sustained scientific observation in shaping effective environmental policies.