The BTO’s Winter Thrushes Survey has just entered its second winter season. As we write, the first tens of thousands of immigrant thrushes are arriving from their continental and Icelandic breeding grounds. So now is a good time to set a route for a winter walk for the survey from which you can report your observations over the winter. The overall aim of WTS is to quantify thrush numbers, feeding locations and food as the winter period progresses, all in far more detail than ever before. By including a second winter, we can begin to document differences between winters for the first time.
Examples of ‘Choose a square’ on the Winter Thrushes website. Orange squares are vacant ‘core squares’ and blue squares are already selected. If you don’t want a ‘core square’ you can choose any square you like.
Why a survey on winter thrushes?
Although we know much about the timings of arrival and departure in the UK through BirdTrack, the general patterns of distribution of our winter thrushes through atlas work, and about the way thrushes use gardens through our Garden BirdWatch and Garden Bird Feeding Survey, many important questions still remain unanswered.
For example, how many birds come? Current midwinter estimates of about 700 thousand each of Redwing and Fieldfare) are the best we have but originate from the 1981–84 Winter Atlas and even then were considered to be of low reliability. Is the UK an internationally important haven for winter thrushes, as we suspect?
What is it exactly that brings them here? We know little about thrushes’ choices of habitats or how their feeding behaviours vary by species, geographically and through the winter. A better understanding of such issues, including the relative importance of key habitats such as farmland, gardens and orchards and of the various feeding resources, will benefit these species’ future conservation.
Success in 2012/13
Last winter over 1,600 volunteers carried out counts for the Winter Thrushes Survey between September and April and submitted their data online. More than 3,300 different locations were covered and more than 12,600 visits were made overall. Although coverage in England was highest, with more than 2,400 sites visited, we were pleased that more than 400 sites in Scotland, over 300 in Wales and over 100 in Northern Ireland were also included in the survey.
Though most sites had been selected by the observers themselves, more than 1,400 were ‘core sites’ which had been selected randomly prior to the survey for a coordinated midwinter count. Data from core visits will be used to produce new estimates of midwinter numbers. Far and away the best contribution came from Sussex, where 65 core visits were made. The Birmingham & West Midlands region scored 31 and in eight other BTO regions survey volunteers covered 20 or more squares: Berkshire, Buckinghamshire, Co Down, Fife, Hampshire, Norfolk Northeast, Yorkshire (Richmond) and Yorkshire (York). Smaller totals are no less impressive in regions with few resident observers or with rough terrain.
How to help
Fieldwork is very easy and for many birdwatchers will just be an extension of their patch birding. All the records can be entered online on the BTO website, or submitted on paper. The basic information collected on each visit is the pinpoint location of each sighting of thrushes, Starlings or Waxwings, the number and species of birds at each point and a broad categorisation of their habitat and behaviour, with feeding location and food where known.
We are very grateful for the support the survey has been receiving. From last winter’s observers we are just looking for more of the same. There are two ways that new observers can join in:
1. Choose your own area to survey – set a route that suits you, 1–3 km long and based loosely on a 1-km square, and walk it as many times as you like between now and April.
2. Take on a ‘core survey square’ – core squares have been selected randomly for a synchronised midwinter visit between 27 Dec and 10 Jan. You can make as many additional visits as you like.
Your help will be greatly appreciated!
For further information, please explore the survey’s web pages at http://www.bto.org/volunteer-surveys/winter-thrushes
Dawn Balmer & John Marchant