BTO/JNCC WINTER FARMLAND BIRD SURVEY - WINTER 2002/2003
INSTRUCTIONS FOR FIELDWORKERS
SURVEY AIMS
To gain insights into the numbers and species of birds using different agricultural habitats or crop types in
winter. The survey will run over three winters and began in 1999/2000 – this is the final winter postponed from
2001/2002 due to the Foot and Mouth disease outbreak. We aim to survey the same squares in each winter.
CHANGES AND IMPROVEMENTS SINCE 1999/2000 – no changes have been made since 2001/2002
Many thanks for comments in 2000 - we tried to take these into account and improve the survey where possible.
As a reminder, these were the 6 key changes:
1. Transects are no longer required. This is in part a response to comments, but also because we feel we
have gained sufficient data from one year of transect coverage.
2. We have given the option of recording extra species.
3. Some parts of the instructions have been clarified, not least the interpretation of the time limit.
4. Several habitat codes have been added at the request of observers.
5. The forms have been improved for easier use in the field.
6. Simple classifications of available boundary habitats are required this winter.
METHODS
1. Divide your 1-km square into patches of agricultural habitats (usually a patch = a field).
2. Visit your square three times per winter between November and February, with at least 2 weeks between
visits. Use the white forms for field visits and transfer to the blue ‘top copies’.
3. On each visit walk around as many fields as possible within 4 hours, counting birds and describing habitat.
4. Surveying is difficult (and unpleasant) during poor weather - try to avoid heavy rain, strong winds and poor
visibility (although lying snow is OK).
5. If the square was surveyed last winter, please start by surveying the same patches as before
(number them the same too - last year’s map is copied on the reverse of the Visit Summary Form).
Since transects are no longer required you may have time spare to survey more patches in addition to those
surveyed last winter.
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WE DO NOT EXPECT YOU TO SURVEY THE WHOLE SQUARE - THE MAXIMUM AMOUNT OF TIME YOU
SHOULD SPEND ON EACH VISIT IS 4 HOURS, COVER AS MUCH AS YOU CAN WITHIN THIS TIME
PERIOD - ideally spend between 2 hours and 4 hours surveying per visit and record the remaining patches as
uncovered. On subsequent visits cover at least the same part of the square and if you have time, continue on
into previously unvisited parts of the square.
Which habitats to survey?
When dividing your square into patches of similar habitat (e.g. fields) please only include patches containing the
following habitat types found on farms and small-holdings:
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Arable fields - any stages of growth of crops, stubbles, bare tillage, flower/bulb fields but not tree nurseries;
Set-aside/fallow - typically grassy/weedy fields;
Permanent and temporary pasture - include downland and grazings for sheep, cattle and horses but
exclude upland rough grassland (above 300m altitude);
Farmyards - including the yard buildings, farm house and garden (but no other gardens);
Field boundaries - include hedges, dykes etc;
Orchards;
Livestock fields including open-air pig and poultry farms;
Woodland, including small farm woods - only survey the outer edge (2m wide) from the adjacent patch and
treat as a boundary, i.e. like a hedge (see page 3).
Do not count birds within woodland, fish farms, watercress beds, plant/shrub nurseries, allotments, rarebreeds/childrens’ farms, animal sanctuaries, plantations, common land, grazed heathland, grazed saltmarsh,
grazed airfields or grazed cemeteries.
When defining patches, uncropped strips (e.g. grass strips, wildflower strips) around fields that are narrower
than 20m wide should be included as integral parts of the main field rather than patches in their own right.
Narrow strips of game cover crops should be defined as separate patches.
On the front of the Visit Summary Form is a photocopied map of your square (at a scale of 3cm:250m).
 On your first visit check and amend patch (e.g. field) boundaries as appropriate. Include new boundaries
and temporary fencing - divide and number such fields as separate patches even if the habitat is identical
on either side since the two halves may change through the winter (e.g. different grazing).
 Label all the farmland patches with consecutive numbers starting from 1 (see example). This is very
important! If the square was surveyed last year, wherever possible please label the patches with the
same numbers as last year. If a patch has been split up since last year, use the next available numbers to
label the new bits of the patch (e.g. patch 1 becomes patch 1 and patch 27). If 2 or more patches have now
been combined, label this year’s patch with the lower of the numbers and do not allocate the higher number
to any other patches (e.g. patches 1 and 2 become patch 1, patch 2 remains blank on the form).
 Identify all the non-farmland patches clearly with cross-hatching (see example).
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Which bird species?
The focus of this survey is 30 Priority Species of farmland birds (see Codes Sheet) including declining
farmland species of conservation concern (e.g. Tree Sparrow), scarce or localised users of farmland (e.g. Snow
Bunting) and representatives of widespread species that use farmland in winter (e.g. Pied Wagtail). These
species should be counted on every visit. You can select which other group of species to survey:
 Optional species - a range of farmland/hedgerow species but not woodland species (see Codes Sheet).
 Gulls - can be time consuming to count - tick in Yes or No column on Visit Summary Form if surveyed.
 Woodpigeon - can be time consuming to count - tick in Yes or No column.
 Black crows - Rook, Carrion Crow and Jackdaw can be time consuming to count - tick in Yes or No column.
Prior to the survey decide which set of species you wish to survey. Though we have given the option of
ignoring the three problem groups we would greatly value counts of these species. Whichever set of species
you chose to look for, tick the appropriate box(es) on the Visit Summary Form and then survey all of that group.
Remember, tick what you surveyed (i.e. what you looked for) even if none were actually present.
Bird Surveying
To accurately count birds on farmland in winter you need to walk around fields - the survey cannot be done
adequately by viewing fields from public rights of way. This means that you will need to speak to farmers on or
before your first visit - most will be happy for you to walk around the edges of fields, many are keen to know
what birds live on their farms and can be very helpful, especially when identifying crops. The formal ‘Letter of
Introduction’ included with this pack should be helpful when meeting farmers.
At the start of the visit note the date and start time in the boxes provided on the Visit Summary Form. If you can
only survey some of the patches (e.g. time limitation), try to start the survey near the middle of the square if
possible and cover patches that fall wholly within the square rather than those that fall across the square
boundary. If you have time, continue by surveying the fragments of peripheral patches that fall within the
square. For such patches do not include the edge of the square as a boundary.
For each patch, walk around the perimeter and allocate all birds
seen to one of the following zones (see diagram, right of a
simplified patch and these zones):
The patch boundary - features such as hedges or stone walls,
plus any ‘verge’ vegetation between that
and the crop or uncropped margin;
The patch margin the outer 20m of the crop;
The patch interior everything beyond 20m into the crop.
Patch margin
Patch interior
When surveying fields, birds should be recorded in the zone in which
they are first detected - if a bird is flushed from the margin into the
Patch boundary
hedge, it should be recorded in the margin. However, if a flock is
continually moving between the margin and the hedge, record them
in the margin category since this is likely to be where they are
feeding. If a field is so narrow that the whole of it is taken up by the
margin zone (i.e. less than 40m wide) record birds in either the boundary or the margin since there is no interior.
Do not survey woodland except where it abuts a field and then only record birds in the outer 2m of the wood, i.e.
as if it was a hedge and allocate birds to the boundary of the patch you are in using the suffix TH for ‘tall hedge
or wood edge’ (see next page).
For orchards, farmyards and gardens record everything as being in the boundary or interior (no margin).
During the survey take care not to count the same birds twice (a matter of judgement). Please also take care to
scan field vegetation carefully for skulking birds, flocks etc. Do this at least once on each side of the field (e.g.
at positions indicated by the dots on the diagram).
Ideally you should walk around each field separately. Inevitably this means walking down both sides of some
boundaries. Only where the boundary is open (e.g. fence line, low wall or ditch) can you survey both sides of
the boundary from one field. If you see birds in an adjacent patch record these sightings in the usual way,
taking care to avoid counting the same birds twice.
Every time you encounter a bird or flock, enter the patch number (from your map) in the first column of the bird
section of the Bird and Habitat Form and the species code, then enter the number of that species seen in each
zone of the field. You do not need to enter zero for a species in the other zones. Only enter details of species
you see - i.e. if you saw no Redwings there is no need to enter a zero for each patch.
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For boundaries divide birds and flocks in to the following different boundary types:
LH = Low hedge (less than 2m high)
D = Ditch or other water course
TH = Tall hedge (more than 2m high) or wood edge F = Fence line or wall
TL = Tree line (e.g. shelter belt)
V = No structure, just vegetation between crops
B = Buildings
X = Other boundary type (describe separately)
Record this in the Boundary column of the Bird and Habitat Form using the codes above as suffixes after the
number of birds in each boundary type (e.g. 10TH, 5LH means 10 birds in tall hedge and 5 in low hedge).
Birds in flight should not be counted unless they are clearly associated with a patch or boundary. Birds that are
about to land or just flushed should be included - as should raptors and owls hunting over patches, but not, for
example, a flock of Fieldfares flying over. Any birds not conclusively identified (e.g. flushed partridges or distant
finches) should be ignored.
Field Habitat surveying
For each patch surveyed for birds we need a field habitat code and a boundary habitat code. Since cropped
field habitats change so much during the winter we need a field habitat code for each visit.
On your first visit select the field habitat code that best describes the majority of the habitat for each patch.
Enter the code in the Patch habitat column of the habitat section of the Bird and Habitat Form against the
appropriate patch number. If the habitat changes within part of a patch on a later visit use the code for the
majority of the field. If for some reason you cannot visit certain farmland patches, enter an X in place of a patch
habitat code. This is important because then we know that the lack of birds for such patches on the bird section
of the Bird and Habitat Form is because the patches were not surveyed rather than being poor for birds.
See the Codes Sheet for details about how to use the codes. On the inside of the sheet are some brief
explanations of some of the codes and pointers to identifying crops. If you are still unsure do not guess - please
ask the farmer or assign a more general code.
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Boundary Habitat surveying – continued from 2000/01
For each patch please list, in decreasing order of importance, the boundary types present using the 8 types
described above (LH, TH, TL, B, D, F, V and X). For example, if a boundary consists mostly of tall hedges but
with a short section of fence write “TH, F” in the Boundary habitat column. If there are equal amounts of two
types record with an equals sign (e.g. TH=V for a field with half its boundary as tall hedge and half vegetation
only).
Fieldworkers should not put themselves in a position which would place them, or others, in danger. The BTO does
not take responsibility or liability for any actions and subsequent consequences from the activities of fieldworkers.
If you run out of forms either download extra copies from the BTO’s web page at www.bto.org or contact Simon Gillings at
the address below or telephone 01842 750050, fax 01842 750030 or e-mail wfbs@bto.org
At the end of the winter return completed forms to your Regional Rep. If you do not have a Rep return to:
Winter Farmland Bird Survey, British Trust for Ornithology, The Nunnery, Thetford, Norfolk, IP24 2PU.
Please return completed forms by 31st March 2003
PTO for examples of completed forms 