UK's Warmest Spring on Record Boosts Breeding Success in Several Songbird Species
During the spring and summer months of 2025, the UK experienced its warmest spring on record, leading to above-average breeding success in 14 songbird species. This period, from May to August, included species such as chiffchaff, garden warbler, whitethroat, coal tit, blue tit, great tit, and robin.
Data collected by the British Trust for Ornithology's Constant Effort Sites scheme, which monitors 29 songbird species through consistent methods at fixed locations, revealed that the milder and drier conditions of 2025 contributed to this improved breeding success. This favorable weather potentially allowed some birds to raise second broods, increasing productivity compared to the wet spring of 2024.
Among migratory birds, chiffchaff, reed warbler, blackcap, garden warbler, and whitethroat showed above-average breeding successes. Resident birds with statistically significant breeding increases included coal tit, blue tit, great tit, Cetti’s warbler, long-tailed tit, robin, dunnock, chaffinch, and goldfinch.
However, not all species fared well; willow warbler and garden warbler numbers were recorded at their lowest ever in 2025. Moreover, despite some species experiencing better breeding outcomes, overall adult numbers of popular songbirds declined due to a poor breeding season in 2024 and ongoing long-term population decreases.
The impact of climate breakdown poses further risks to wild bird populations. The current Red List of Birds of Conservation Concern highlights declines mainly among farmland species such as skylark, starling, woodcock, house martin, house sparrow, and swift, emphasizing the need for continued monitoring and conservation efforts.
