God rest ye chilly gentle Wren

01 Dec 2010 | No. 2010-12-61

The recently launched British Trust for Ornithology (BTO) Roosting Survey is already yielding exciting results. Householders across the UK are watching hundreds of birds come in to roost in their gardens during the freezing weather, with the tiny Wren scrumming down in the greatest numbers. 

Wrens are piling into nest boxes

Harsh weather presents a substantial problem for small birds striving to survive the long winter nights. Few come smaller than the Wren but householders appear to be providing them a lifeline through a network of cosy bedrooms. Results just in from the BTO’s Roosting Survey show that Wrens are piling into nest boxes, bespoke roosting pouches and even old House Martin nests to stay warm overnight, with most (26%) roosting in groups of 5–9 individuals and, in one nest box in snowy Devon, 30–34 individuals recorded snoozing together.

The most frequent roosting visitor is the Blue Tit but this feisty acrobat usually sleeps alone, with most records (63%) being of solitary individuals. Similarly, Great Tits have tended to bed down alone. The familiar House Sparrow has, however, been its usual gregarious self, with few (8%) opting to go solo, most (42%) roosting with at least four others and, in one instance in West Sussex, ten individuals roosting together.

The survey is also revealing a great diversity of roosting birds in our gardens. Perhaps the most unusual visitor is the Treecreeper which has made a single appearance, although a Dunnock spending the night in a roosting pouch in South Humberside has been a turn up for the books. Squeezing more than one Robin in a nest box seems unlikely given their fierce territoriality, but two snuggled up together in Greater London earlier this month.

The BTO Roosting Survey runs throughout the 2010-11 winter, and it is great fun to take part. For more information, go to www.bto.org/gbw.

Dr Tim Harrison, of the BTO Garden Ecology Team, commented: “The survey is beginning to show fascinating roosting patterns in many species. The tits tend to sleep alone, while Wrens and House Sparrows seem to prefer the company of others. We are aware of how much nest boxes are used during spring but, with the help of the public, we are now beginning to appreciate how important these and other cavities might be to roosting birds during winter.”

He added: “We really want to encourage other householders to get involved with this simple survey. Being in the grip of an unusually harsh winter, now is a great time to find out more about how important our gardens are for roosting birds. With urban temperatures being that bit warmer than in the wider countryside, garden nest boxes and roosting pouches could prove the difference between life and death.”

Notes for Editors

  1. BTO Roosting Survey. Participants choose one evening this winter to see if, and how many, birds use a nest box, roosting pouch, or natural cavity in their garden to spend the night. Observations can be made using a nest box camera, by eye at dusk, or by counting bird droppings in the nest box in the afternoon before and the morning after the sleepover evening. For more information see: www.bto.org/gbw.
  2. 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.

Contact information 

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: 07585 440910 (anytime)
Email: press [at] bto.org

Images are available for use alongside this News Release
Please contact images [at] bto.org quoting reference 2010-12-61

The BTO has an ISDN line available for radio interviews
Please contact us to book an interview
Office: 01842 750050 

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