The warmest and sunniest spring on record this year has led to a surge in breeding for some of Britain’s best-loved songbirds, data shows.
Scientists said the dry, warm spring had offered a glimmer of hope for threatened wild birds. During the 2025 breeding season, from May to August, breeding success was above average for 14 species, including the chiffchaff, garden warbler, white-throated, great tit, blue tit, great tit and blackbird.
In 2025, volunteer bird ringers from the British Trust for Ornithology monitored 29 songbird species at specified locations as part of a project known as the Constant Effort Sites Program.
Participants capture birds in the same location and in the same way throughout the summer, allowing scientists to see how the number of newly fledged adults and young change over time and whether they survive better or worse than in previous decades.
Compared to the very wet spring of 2024, the 2025 breeding season saw above-average success.
Dr Ellie Leech, ringing program manager, said: “Thanks to the fantastic efforts of BTO bird banders, we know that the breeding success of 14 species was above average in 2025, largely due to mild weather. This is good news.”
Leech said the contrast between the sunny, dry spring of 2025 and the continual downpours of 2024 couldn’t be more stark. “[It] shows how important the weather can be; this is particularly true for young birds which are less well insulated and less experienced in finding food in difficult conditions.
Above average breeding success has been recorded for migratory birds including Chiffchaff, Reed Warbler, Black-headed Warbler, Garden Warbler and White-throated Warbler. For resident birds, nine species – black tit, blue tit, great tit, Cetti’s warbler, long-tailed tit, blackbird, dunnock, finch and goldfinch – recorded statistically significant increases in reproduction compared to the five-year average.
The report states: “It is likely that all species benefited from the mild, dry weather of spring and summer and that the prolonged good weather of summer 2025 increased the probability of second broods, leading to higher productivity. »
Despite the above-average breeding success of 14 species, adult numbers of some of the most popular songbirds declined this year, which was attributed to last year’s poor breeding season.
For the willow warbler and the garden warbler, the numbers recorded in 2025 were the lowest on record.
Leech said the effects of climate change could worsen the situation for wild birds, with several regularly monitored species showing long-term declines.
Britain’s wild birds continue to experience serious decline. The most recent Red List of Birds of Conservation Concern, which lists species at risk of extinction, includes much-loved British birds such as the Skylark, European Starling, Woodcock, House Swallow, House Sparrow and Swift.
Most of the declining species are farmland birds, according to the RSPB, which says intensive agricultural practices, including the use of pesticides and fertilizers, are the main driver of declining bird populations.
