Winter Farmland Bird Survey

Newsletter - September 2001

Final winter of the Random Square Survey postponed
– Winter Walks and Casual Records go ahead

This year’s Foot & Mouth disease outbreak was first detected in February, during the final two weeks of the Winter Farmland Bird Survey (WFBS) season.  The British Trust for Ornithology (BTO) was quick to act in suspending many of our fieldwork projects through the spring and summer of this year. Most of our fieldwork can only be carried out with the support and co-operation of landowners across the country. It was vital that our good relationships with landowners were not jeopardised and that caution and sensitivity to the plight of the farming community was utmost in our minds.  Although the number of outbreaks has dwindled from its peak in late March, new cases were still being reported most days through August and September.

Random Square Survey

With uncertainty about the prevalence of Foot & Mouth during the coming winter, and the understandable caution being exercised even in disease free areas, we thought it wise to postpone the third winter’s fieldwork for WFBS Random Square Survey.

However, it is vital that we do complete the third winter of the survey, in order that between winter variations in farmland bird numbers are fully documented.  It is therefore intended that the final winter’s fieldwork will now take place in the winter of 2002/2003 and we very much hope that all participants are able to continue next year, after this winter’s sojourn.

Winter Walks and Casual Records

Most Winter Walks routes and Casual Record observations are from public rights of way such as tracks and footpaths.  As these surveys do not require access to the farmland itself, it may be possible to continue with these surveys this winter in most areas.  We very much hope that all who have participated in the last two winters will be able to continue gathering the wealth of data during the coming winter.  Indeed, we hope that Random Square surveyors will be able to contribute to these surveys during the coming winter, although we must stress the importance of those individuals to revert to the Random Square Survey in it’s final winter next year.

At the time of writing, restrictions were still in place in several areas, particularly across the north of England.  Even where footpaths are open, we urge all BTO volunteers to exercise caution.  If you are unsure whether your survey site is within a restricted area, check details on the DEFRA web site (www.defra.gov.uk/animalh/diseases/fmd) or contact Andy Wilson at the Nunnery.

Copies of the Winter Walks and Casual Record forms can be printed from the BTO web site or by contacting Andy Wilson at The Nunnery.

A big thank you to all WFBS contributors

There can be no doubt the WFBS is an ambitious survey and as such it has provided challenges for fieldworkers, regional organisers and BTO staff alike.  Now that we are able to take stock of what has been achieved in the first two winters of the survey we think that all volunteers should be proud to have contributed to such a wealth of valuable data.  The task of inputting the data for the first two winters has been enormous but we are now able to start analysing these data and present a few preliminary findings in this newsletter.

The government has pledged to reverse farmland bird declines by the year 2020 (see Farmland Bird Indicators below).  This will only be possible if policy is underpinned by sound scientific advice on how this might be achieved.  WFBS will play a vital role in this process.  We very much hope that you will continue to contribute over the next two winters to this very important project.

Over four million birdscounted in first two winters

The fruits of our volunteers’ efforts over the winters of 1999/2000 and 2000/2001 are now being realised as we start the process of analysing the wealth of data gathered.  And what a wealth of data!  Our Winter Walks surveyors covered almost 500 routes over the two winters, counting almost one million birds and in the process walking a total of 18000km – that’s the equivalent of walking from Land’s End to John o’ Groats and back six times!  Over 12000 Casual Records have been submitted relating to around two million individual birds.   During the winter of 1999/2000 our Random Square surveyors covered 869 1-km squares, counting no less than 350000 birds – while almost double that number was noted in the second winter when more species were included.

Table 1 shows that coverage for most of the target species was excellent.  Chaffinch was the most widespread species but Starling was the most numerous – a total of almost 600,000 was noted in the 1999/2000 winter!

Table 1.Totals counts of the 30 target species in the winter of 1999/2000 (Farmland indicator species in bold, woodland indicators in italics – see below)

Comparing the percentage of Random Squares in which each species was recorded with the percentage of Winter Walks on which they were noted shows much agreement between this measure of how widespread each species is (Figure 1).  Most species were found on a slightly higher proportion of Winter Walks than Random Squares – a difference that is to be expected as many Winter Walks routes were covered more frequently than the three visits required to Random Squares.

Figure 1. Percentage of Random Squares and Winter Walks in which each of the 30 target species was recorded in 1999/2000

Figure 1 does reveal that some species, notably Lapwing was recorded on a much higher proportion of Winter Walks (42%) than Random Squares (21%).  This may be partly due to the fact that Winter Walks surveyors could include counts of Lapwings some distance away from their route while only the birds present within the Random Squares were counted.  Only two species were located on a higher proportion of Random Squares than Winter Walks: Grey Partridge and Snipe.  These are species that sit tight, often in dense vegetation and are therefore more likely to be detected using the field by field survey method adopted by the Random Square Survey.  This shows how the three different elements of WFBS complement each other.  It is only by looking at the three data sets in unison that we will get an accurate picture of densities, distribution and habitat associations of the diverse range of target species covered by WFBS.  

Winter Walks and Casual Records will give particularly useful information on species that form large flocks, especially Golden Plover and Lapwing.  Golden Plover, for example, were noted in only 61 random survey squares (Figure 2a) and while the data gathered in these squares will provide valuable information on habitat associations, it will not give a good indication of the geographical range of Golden Plover and how this might change through and between winters.  Far higher numbers were recorded on Winter Walks and especially through Casual Records, providing a much better indication of the winter range of this species and where the main concentrations are found (Figure 2b).  It is interesting to compare this with the distribution of Golden Plover recorded for the BTO’s Winter Atlas between 1981 and 84, which doesn’t show such a high concentration in the east of England (see Atlas of Wintering Birds in Britain and Ireland, P.Lack, (1986), Poyser).    

Figure 2.  Distribution of Golden Plover on Random Squares and from Casual Records in the winter of 1999/2000

Winter habitat association of finches

One of the main aims of WFBS is to determine which farmland habitats are most important for each of the target species and to see whether these change through the winter, between winters or between different parts of the country.

Figure 3.  Habitat preferences of sparrows, finches and buntings

Preliminary analysis of the Random Square Survey data from the 1999/2000 winter demonstrates the importance of stubbles to most of our finches and buntings.  Jacobs Preference indices were calculated for each species to give an indication of relative densities across different field types.  A preference index of –1 indicates a habitat that is completely avoided while a preference index of +1 would only occur where all individuals of that species were found in one habitat.  Figure 3 shows that for most sparrows, finches and buntings, cereal and other stubbles, have positive preference indices - one exception being Corn Bunting, which may be due to the very small sample size for this scarce species.  The habitat data collected for WFBS show that over 80% of farmland during the winter months is either cereal crops, grassland or bare earth, which, as can be seen in Figure 3 is little used by most of these seed eating passerines.

Lowland Grassland Survey

Please note that the Lowland Grassland Survey that was initially planned for summer 2001 is on schedule to proceed in 2002. It would be helpful if you could make it known to your regional representative of your wish to take part in the survey. If you received instructions for 2001 please retain these for next summer, otherwise ask the BTO for replacements again via your regional representative. Further details will be circulated nearer Christmas 2001.

Thank you - Ian Henderson

The Farmland Bird Indicator

In 1998, the government launched its Indicators of Sustainability. One important element of the indicators is the subset of 15 key ‘headline’ indicators. These are intended to raise public awareness and focus public attention on what sustainable development means, and to give a broad overview of whether we are achieving a ‘better quality of life for everyone, now and for future generations to come’.

The 15 headline indicators thus make up a ‘quality of life barometer’, which will be used to measure overall progress. They cover the three pillars of sustainable development, namely social progress, economic growth and environmental protection.

One of the 15 headline indicators is the wild bird indicator.  The reasons given for the inclusion of this indicator were: “We value wildlife for its own sake and because it is an integral part of our surroundings and our quality of life. Birds are recorded as good indicators of the broad state of wildlife and the countryside, because they are wide-ranging in habitat distribution and tend to be at or near the top of the food chain.”

The wild bird indicator, produced by a collaboration between the BTO, RSPB and the Department for Environment, Food and Rural Affairs (DEFRA), makes extensive use of BTO data to provide an overall measure of breeding bird population change in the UK.  A total of 139 species are included in the indicator, rare or introduced species are excluded.  In addition to the overall indicator, separate indicators for farmland and woodland bird species are calculated.  These show that while there been a modest drop in woodland bird numbers, farmland bird populations have been in steep decline since the mid 1970s.

While a range of BTO schemes provide information on breeding population changes (e.g. Breeding Bird Survey and Common Birds Census) and breeding success (e.g. Nest Records Scheme & Constant Effort Sites Ringing) for these indicator species, we have relatively little data to research the winter ecology of these birds.  For some of these species, changes in winter survival could be contributing to the downward population trend shown by the farmland indicator.  Twelve of the 20 farmland indicator species are covered by WFBS along with four woodland indicator species (see Table 1).  WFBS data will provide vital information on the ecology of these birds during the winter months. 

Figure 4.  The National Wild Bird Indicator

Winter Mammal Survey

You may be aware that the BTO and The Mammal Society are carrying out a pilot study this winter to look at how a multi-species mammal monitoring scheme might work. This important project is funded by the Department for Environment, Food and Rural Affairs (DEFRA) and its results will be used as a basis for long-term future mammal monitoring in the UK. We will be carrying out two separate surveys jointly with The Mammal Society.  The first of these will be a sightings transect, based on 1-km squares across Britain.  BBS fieldworkers and other volunteers will be asked to walk line transects of standardised length within their allocated 1-km squares recording all the mammal species that they see. This will be followed by sign transects later in the winter, where observers will be asked to survey slightly longer transects within the same set of 1-km squares, using standardised techniques to look for the characteristic field signs of a range of target species, such as Badger latrines, Harvest Mouse nests and molehills.

You may be wondering why we are running this pilot survey when the WFBS random square surveys have been cancelled this winter because of Foot & Mouth Disease. The simple answer is that the two surveys are being organised differently and have different requirements, so different conclusions have been reached. The WFBS is in its final year and it is important to keep the same protocols & cover the same areas as in previous years. It also requires observers to walk directly across farm fields whereas for the Winter Mammal Monitoring pilot, observers follow linear features and rights of way, much as the Winter Walks and Casual Records components of WFBS do. Also, the Winter Mammal Monitoring study is a pilot and so we can test our methods, even if we do not get data from every area of the country because of Foot & Mouth Disease problems there. We have provided comprehensive guidelines about Foot & Mouth Disease in our information pack.

Ideally, we would like observers to carry out both parts of the survey in their WFBS square so that we can make direct comparisons between the two methods. However, observers can opt to take part in just one of the two parts of the survey. One aspect of this pilot is to examine the results gathered by different groups of volunteers, from those trained on The Mammal Society's 'Look Out for Mammals' courses, through BBS fieldworkers already recording mammals in the summer, to other fieldworkers perhaps with less experience of mammals. So whatever your level of experience, why not get involved in this pilot? The future of multi-species monitoring for mammals starts here, so be part of it!

To find out more or to volunteer to take part please contact the BTO on 01842 750050 or e-mail .

Mike Toms

drawing by Mike Toms

This newsletter was edited by Andy Wilson and Simon Gillings.  Several BTO staff have been heavily involved in the enormous task of inputting and analysing WFBS data and we would especially like to thank Peter Beaven, Greg Conway, Su Gough, Heidi Mellan & Nicki Read for their hard work.  Comments or further information should be addressed to: Andy Wilson, BTO, The Nunnery, Thetford, Norfolk, IP24 2PU.  Tel: 01842 750050.  E-mail: wfbs@bto.org

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