New results from the British Trust for Ornithology’s (BTO’s) Garden BirdWatch suggest that the harsh winter could be having lasting effects on Britain’s smallest bird.
It’s not easy being a small bird, particularly during freezing weather. Weighing a mere 6g – less than a ten pence piece – the Goldcrest appears to have suffered substantially this winter, occurring in 48% fewer British and Irish gardens from January–March 2010, compared with the long-term average (as calculated from 1995–2009). Although the decline was widespread, regional differences were apparent, with massive 60% losses in three corners of the UK: north Scotland, south west England and eastern England (see map below).
Goldcrests use gardens increasingly during winter as they feed on fat-based foods provided by householders. During severe winter weather a greater proportion of the overall Goldcrest population would be expected to use gardens, so the substantial decline in BTO Garden BirdWatch observations suggests a crash in the population at large.
Other small birds also declined. As winter mellowed into spring, the rich trill of the tiny Wren was absent from numerous gardens, with a 22% decline compared with the long-term average. The similarly diminutive Treecreeper, which scuttles up tree trunks in search of invertebrate food, was recorded in 15% fewer gardens from January–March 2010.
Dr Tim Harrison, BTO Garden BirdWatch, commented “The Goldcrest is a ‘boom and bust’ species – after cold winters only a quarter of the autumn population may be left to breed, but numbers can rally with pairs sometimes rearing more than 15 chicks in the following spring and summer. It remains to be seen how the population will shape up after the current breeding season.”
He added “Through their participation in the year-round survey, BTO Garden BirdWatchers, with their weekly reports, have provided an early warning of possible large-scale declines in the Goldcrest – something that the BTO is investigating currently.”
For more information about BTO Garden BirdWatch and for a free enquiry pack, please telephone 01842 750050 and ask for the GBW team, email gbw [at] bto.org or write to GBW, BTO, The Nunnery, Thetford, Norfolk, IP24 2PU.
Notes for Editors
- Decline of Goldcrests: Regional changes in the percentage of British and Irish gardens occupied by Goldcrests from January–March 2010 versus the long-term average (as calculated from January–March in 1995–2009).
- The BTO is the UK’s leading bird research organisation. Over thirty thousand birdwatchers contribute to the BTO’s surveys. They collect information that forms the basis of conservation action in the UK. The BTO maintains a staff of 100 at its offices in Norfolk and Stirling, who analyse and publicise the results of project work. The BTO’s investigations are funded by government, industry and conservation organisations.
- The BTO Garden BirdWatch is the only nationwide survey of garden birds to run weekly throughout the year, providing important information on how birds use gardens, and how this use changes over time. Currently, some 15,000 people take part in the project. The project is funded by participants’ contributions and is the largest year-round survey of garden birds in the world. For more information see www.bto.org/gbw
- The Goldcrest is the smallest bird species in the UK, with adults weighing around 6g. Goldcrest usually inhabit coniferous and mixed woodland but are found with increased regularity in gardens during winter. In harsh winter conditions the invertebrates upon which Goldcrest normally feed become less available, and this problem could be exacerbated by heavy snow. More information on Goldcrest and other garden birds can be found on the BTO website: www.bto.org/birdfacts and www.bto.org/gbw/Species/index.htm
Tim Harrison (BTO Garden BirdWatch Development Officer)
Office: 01842 750050 (9am to 5.30pm)
Email: gbw [at] bto.org
Paul Stancliffe (BTO Press Officer)
Office: 01842 750050 (9am to 5.30pm)
Mobile: 07845 900559 (anytime)
Email: press [at] bto.org
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Please contact images [at] bto.org quoting reference 2010-6-26
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