BTO Bird Atlas 2007-2011
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BTO Atlas - ‘Bird of the Day’ - Click on highlighted text for random daily winter tetrad results.
Bird Atlas 2007-11 is a huge and exciting project that will map the abundance and distribution of birds in Britain and Ireland during the breeding season and winter. It will be fascinating to look at the changes in distribution since the last breeding and wintering atlases. There have been two previous breeding atlases (1968-72 and 1988-91) and just one previous winter atlas (1981-84). Have Buzzards continued to expand? Have Ravens spread eastwards? Have Wood Warblers disappeared from our woodlands? Where do we find Snipe in the winter? Are Siskins in the same places in summer and winter?
So given we have already had three previous atlases, and have regular monitoring through surveys like Breeding Bird Survey, Wetland Bird Survey and bird recording through BirdTrack, why do we need another atlas? It’s important to remember that long-term surveys such as the BBS are sample surveys and provide us with information on trends in populations. They do not aim to cover all of Britain and Ireland; rather they aim to have a good geographical spread of survey sites. Atlases give us the opportunity, about every 20 years, to visit all 10-km squares in Britain and Ireland and tell us what is there and approximately how common they are. It’s a snapshot of bird distribution and abundance in time.
Atlases have provided vital information for bird conservation. One of the important findings from the last breeding atlas in the late 1980s was the widespread range contraction of many of our farmland birds. This led to detailed research into the causes of these declines. Will the results from Bird Atlas 2007-11 show similar results for some woodland bird species? Will the conservation efforts for farmland birds have made a difference? One thing is for sure; the results from this atlas will be the basis for the conservation of birds in Britain and Ireland for the coming decades.
As birdwatchers, many of us are interested in numbers, distribution and change. It will be fascinating to see the changes between the two previous breeding atlases. It’s amazing to think that Little Egret was only recorded as a non-breeding visitor in three 10-km squares in the 1988-91 Atlas and now they are breeding in many counties. Looking at maps for Wood Warbler (Figure 1), we can see a mixture of gains and losses between the two breeding atlases, with an indication of an expanding population in Ireland. Information from BBS suggests a decline of 52% between 1994 and 2004, although the number of plots is quite small (53). What will comprehensive coverage in the atlas period reveal? Given it is over 25 years since the last Winter Atlas, we can also expect to see some significant changes in the distribution of birds in this season. The map for Great Grey Shrike (Figure 2) shows a fairly even distribution across Britain, with just one record in Ireland. Between 1981-84, they were recorded in 239 10-km squares and the winter population was thought to be around 150 individuals (and low during the atlas fieldwork period). In recent years, numbers have been much reduced. Conversely, for Pink-footed Goose (Figure 2) we can expect to see an increase in range and abundance. In November 1983, Pink-footed Goose numbers reached 101,000 individuals and this has increased to around 271,000 in October 2004. The winter distribution map for the 2007-11 Atlas will certainly be different.
Thousands of birdwatchers will take part in fieldwork throughout the Britain and Ireland. We need all your records – whatever you see, whenever, wherever! There are two components to the fieldwork: Timed Tetrad Visits (TTVs) and Roving Records. TTVs involve two visits in the breeding season (April – July) and two in the winter (November – March) to a tetrad (2 km x 2 km square). Each visit is for a minimum of one hour and the idea is to record species you see and hear along with numbers, so we can calculate the relative abundance of species in the 10-km squares. We are aiming to cover a minimum of eight tetrads in every 10-km square (there are 25 tetrads in a 10-km square). Of equal importance are general birdwatching visits to 10km squares (Roving Records) where the aim is to compile a species list of everything you see and hear. We will also be gathering evidence of breeding in each 10-km square as we go along. With over 80,000 tetrads in Britain and Ireland there is a lot of counting and recording to be done!
One of the common questions about Atlas fieldwork is “How can we find all the species in a tetrad in a one or two hour visit?”. It is important to remember that the mapping in the national Atlas is at the 10-km level, even though the fieldwork (TTVs) is carried out at the tetrad level. We don’t expect you to find all the species in a tetrad, because some species are scarcer than others, and some are harder to detect than others. We will be able to calculate relative abundance at the 10-km level by using the information collected during the TTVs at the tetrad level. Pilot fieldwork has shown that by covering a minimum of eight tetrads out of 25 in a 10-km square, we will have enough information to produce good estimates of relative abundance. Fieldwork for the 1988-91 Atlas explored the potential biases in choosing a minimum of eight tetrads (birdwatchers are bound to choose the best ones!) through the Key Squares Survey. The Atlas aims to produce maps of relative abundance and not absolute abundance.
Discovering a rare or scarce breeding bird in your area would be thrilling, but you may also have some concern about the sensitivity of the record. BTO have produced a policy on the mapping of rare and scarce birds in conjunction with the Rare Breeding Birds Panel and a copy of the policy can be viewed at:
http://www.bto.org/birdatlas/taking_part/confpolicy.htm If you have any concerns about a record of a rare breeding bird then you are encouraged to submit details on paper, in confidence, to the Atlas Coordinator at BTO.
Get involved with fieldwork
You can make a real contribution to the Atlas. From 1st November, simply make a note of every species you see and record which 10-km square you are in, and then enter the records online at www.birdatlas.net or fill out a Roving Records form (available from BTO HQ or download from the website). Over 25 counties are also conducting ‘local atlases’ over the period of the national atlas and will be aiming to achieve 100% coverage of tetrads. To help these counties, try to record your Roving Records at the tetrad level where possible.
Bird Atlas 2007-2011 is a partnership between BTO, BirdWatch Ireland and the Scottish Ornithologists’ Club. Fieldwork for the Timed Tetrad Visits is being organised through a network of local Atlas Regional Organisers. To find out more, visit the website www.birdatlas.net where you can or contact the Atlas Co-ordinator at BTO HQ.
The Atlas Regional Organiser for Cornwall is: Stephen Jackson. Tel: 01362 313533 Email: Stephen.f.Jackson@btinternet.com
Dawn Balmer, Atlas Coordinator, BTO, The Nunnery, Thetford, Norfolk, IP24 2PU. Email: dawn.balmer@bto.org
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