Immigrants put strain on scant resources

01 Oct 2012 | No. 2012-37

Reports from across Britain indicate that fruit and seed crops are poor this autumn, suggesting that many birds will face tough times over the months ahead. Competition for tree seeds and hedgerow berries will be fierce, with added strain coming from large numbers of immigrant finches and thrushes, on the move and heading this way from Scandinavia and Eastern Europe. The BTO is calling for volunteers to help monitor these welcome visitors so that researchers can find out which habitats and resources are the most important.

Blackbirds are currently pouring into the country

Britain is a key wintering destination for immigrant thrushes, including the many thousands of Blackbirds, Redwings and Fieldfares currently pouring into the country. Once here, these birds compete with resident individuals for resources, including the berries that adorn our hedgerows, bushes and garden shrubs. With some thrush populations in widespread decline, the BTO is keen to find out how our wintering thrushes are using the resources available to them, highlighting which habitats and berry stocks are used and when.

There are two components to the BTO study this winter:

Out and about – The Winter Thrushes Survey

The BTO needs volunteers, particularly those who walk a regular route, willing to record the thrushes that they see while out and about. By noting the locations of the thrushes that they see and submitting simple notes of what the birds are doing, volunteers can make an important contribution to our understanding.

As John Marchant, the Survey Organiser at the BTO, notes, “This is a survey that anyone can take part in, whether new to birdwatching or an experienced BTO surveyor. There will be a wealth of online resources, from species identification videos, photographs and audio material, to guides on berries, fruit and crops that are likely to be important for thrushes. If you have a regular winter walk, and you see thrushes, then this survey is for you.”

More information on the Winter Thrushes Survey can be found at

From the comfort of your home

A parallel piece of work, organised by the BTO’s Garden Ecology Team, is looking at how thrushes use the berries available on garden shrubs. This aspect of the study is ideally suited to those who watch the birds in their garden and is open to anyone.

Mike Toms, Head of Garden Ecology at the BTO, explains, "We are really keen to involve gardeners and garden birdwatchers in this new project and need their help to build up a national picture of which fruits and berries are available and which birds are using them. In addition to some simple weekly recording throughout the winter, we also need some people to carry out some more detailed work by participating in timed counts of birds eating berries.”

A free enquiry pack, containing more information on the survey, recording forms and advice on making your garden more attractive to birds is available from Birds and Garden Berries Study, BTO, The Nunnery, Thetford, Norfolk, IP24 2PU, by calling 01842-750050 or by emailing gbw [at]

Notes for Editors

  1. 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 14,500 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
  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,  Stirling and Bangor, who analyse and publicise the results of project work. The BTO's investigations are funded by government, industry and conservation organisations.

Contact Details

Paul Stancliffe
(BTO Media Manager)

Office: 01842 750050
(9am to 5.30pm)
Mobile: 07585 440910 (anytime)
Email: press [at]

Mike Toms
(BTO Head of Garden Ecology)
Office: 01842 750050
(9am to 5.30pm)
Email: gbw [at]

John Marchant
(BTO Survey Organiser)

Office: 01842 750050
(9am to 5.30pm)
Email: john.marchant [at]

Images are available for use alongside this News Release
Please contact images [at] quoting reference 2012-37

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

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