Instructions and guidance for the Breeding Atlas

The aim of this part of the Atlas is to determine the distribution and abundance of all birds breeding in Cheshire and Wirral. Our birdlife is changing rapidly. The Breeding Bird Atlas of Cheshire and Wirral was published over 10 years ago (1992) based on fieldwork now over 20 years old (1978-84), and the only mapping survey of the area in winter was in 1981-84 for The Atlas of Wintering Birds in Britain and Ireland, using 10km squares. This Atlas will allow comparison with the breeding birds of twenty years ago; it will produce data for winter, never before mapped in detail; and it will measure the abundance of birds as well as their distribution. It is essential to have as good information as possible on the birds’ present status, and this Atlas will be a key tool to help their conservation.

Fieldwork is planned to cover three breeding seasons (April to the end of June each year) and three winter periods (mid-November to the end of February), from April 2004 to February 2007. Records for other times of year are requested to improve our knowledge, and will be included in the annual Cheshire and Wirral Bird Reports, but they will not be mapped in the Atlas as many birds are moving through our area then. Please e-mail your records for other times of year to; for further advice please e-mail

We hope to achieve as good coverage as possible during the first year of the survey, so please try to carry out the fieldwork in your chosen tetrads during 2004. If you cannot do so, please let your Area Coordinator (names on the enclosed list) know as soon as possible.

The basis for recording is the tetrad, a 2x2km square defined by the even-numbered lines on the National Grid. Use of an Ordnance Survey map is essential; the 1:25000 series is recommended, and a GPS device, if you have one, is very helpful. There is a map provided for each tetrad that you have volunteered to cover. For supplementary records from other areas that you visit, please identify the appropriate tetrad from the enclosed list.

Please feel free to visit your chosen tetrad as often as you like and to spend as long as you like on survey visits. If you cannot visit very often, the minimum to achieve reasonable coverage is to survey your tetrad twice, at least four weeks apart, once between the beginning of April and middle of May, and once from the middle of May to the end of June. Such visits should last at least two hours to stand a reasonable chance of finding all species. We aim to get as complete coverage as possible, so please plan to visit every type of habitat within the tetrad that is likely to hold any different species. Try to conduct your surveys during periods when birds are most likely to be detected, by sight and sound – preferably in the early morning, avoiding extremes of weather (heat, cold, wind and rain); if such conditions are unavoidable, please make a note of the weather in the ‘general comments’ box at the end of the form.
Record every species that you see or hear that is using the tetrad for breeding. Do not include birds that are merely moving through the area (such as gulls, corvids or herons, unless there are breeding birds in the tetrad) or passage migrants. As well as identifying them, watch and listen to find out what the birds are doing, and record the highest level of breeding status (the category closest to the bottom of this list) for each species in the tetrad, using the codes:

O         Bird Observed (seen or heard); no more knowledge of the species' status or of habitat suitable for breeding
H         Species present in suitable nesting Habitat; no other indication of breeding
S          Singing male heard, or breeding calls heard
P          Pair observed in suitable nesting habitat
D         Display or courtship
N         Bird visiting a probable Nest site
B         Birds seen Building a nest, carrying nesting material, or excavating nest cavity
A         Agitated behaviour or anxiety calls from adults suggesting a nest or young nearby
I           Active brood patch on trapped bird, probably Incubating
DD       Distraction Display or injury-feigning from adults
UN       Recently Used Nest (used this season), or egg-shells
ON      Occupied Nest in use (e.g. high nest or nest-hole whose contents cannot be deduced)
FY       Adults carrying Food for Young
RF       Recently Fledged young, still dependent on parents
FS        Adults carrying Faecal Sac away from nest site
NE       Nest with Eggs, or adult sitting on nest
NY       Nest with Young, or downy young of nidifugous species

The first two categories (‘O’ and ‘H’) are the ones that most often cause problems for some observers. Those recorded as ‘O’ are of limited value - because they tell us nothing about the possible breeding status - and will not be mapped in the Atlas, although they will be entered into the CAWOS database. So, please try to observe what the bird is doing and use a higher level of coding if appropriate. On the other hand, birds listed as ‘H’ must be in the normal breeding season for that species, and in suitable nesting habitat. It is not sufficient merely to see a bird during the April-June period.

It is only necessary to record one code of breeding status - the one closest to the bottom of the list - for a species in each tetrad. If, for instance, you find NY on your first visit, you do not need to record any more, although finding the species breeding in different habitats will be useful information. But if you find a species with activity corresponding to one of the single-letter codes, please try to find further evidence to upgrade it to one of the higher levels (a two-letter code) of breeding status on a subsequent visit if you can.
Note that, to record breeding birds, it is not necessary to find nests and please do not approach a suspected nest-site unless you know what you are doing. However, please consider completing a BTO Nest Record Card for any nests found (contact the Atlas Coordinator for advice). For those species on Schedule 1 of the Wildlife & Countryside Act 1981 (marked with shading on the record sheet) it is an offence to disturb them whilst at or near a nest, or with dependent young, unless you have a special licence.
An asterisk * denotes a ‘county rarity’ for which a reporting form should be completed. If you find a rare breeding species for Cheshire and Wirral, please contact the Atlas Coordinator or County Recorder as soon as possible, so that the record can be followed up.

If you are not sure of a record, do not include it. Record only what you find, not what you expect to be there. If you are told of a bird’s presence please do not rely solely on hearsay evidence, but try to see or hear the species yourself.
Please enter on the recording form the dates of your visits and the length of time taken: please spell out the month as April, May or June so that the date is written as, e.g. ‘5 June 2004’ rather than 5/6/04, to avoid confusion with American-style date formats which put the month first.

Extra visits can be made at any time. Visits before April and after June might be helpful in recording the earliest and latest breeding species, and visits at night will be useful for finding the nocturnal species. For extra visits please put the breeding status code and date in the ‘comments’ column for the species.

If you are covering a tetrad on the boundary, shared with another county, please ensure that you cover all of the habitats within Cheshire.  Ideally, if time allows, visit the whole of the square and record birds in all of the tetrad, even though some of it is not in Cheshire, but please indicate under comments which species were only recorded outside the Cheshire boundary.
Records from areas other than your chosen tetrad are very welcome. Please use a ‘Supplementary Records Form’ for these, unless you have a lot of records for one tetrad, in which case complete a standard Atlas record sheet.

Any additional comments can be very helpful in interpreting records. Please use the ‘comments’ column alongside each species, or for more general comments, use the box at the end of the form.

Habitat recording
One of the main uses of the Atlas data will be for conservation of birds. To do this, it is important to link the birds to their habitat. Please try to visit every significant habitat type within the tetrad. This may require maps and some local knowledge to identify suitable areas. Local landowners will be able to help if there are, for instance, ponds, woods or reedbeds that are not visible from a road or footpath.

Some species are significantly shifting the types of habitat they use, and work for this Atlas may help us understand some of the changes. Please enter onto the recording form every habitat type in which you found the species breeding, using the habitat codes given on the enclosed list. These codes have been developed by the BTO for use in all sorts of bird recording. They look terribly daunting at first, but don’t worry! You will soon get used to them. Just enter a letter and a number for each type of habitat in which you encounter the species; for instance, A1 = broadleaved woodland, C9 = saltmarsh, F2 = suburban human site, G10 = large canal (more than 5m wide). Some of the codes do not apply for Cheshire and Wirral, such as C1 = chalk downland, but are included for completeness.

One of the key things for habitat recording is to look at the habitat from the birds’ point of view. For example, you might find a Grey Wagtail nesting amongst the roots of a tree on a river bank, and a Blackbird in the same tree; for the wagtail the crucial habitat is the river (G7) but the Blackbird chose the area because of the cattle-pasture (E1) adjacent to the river. The habitat is mainly determined by where the birds find their food, rather than where they nest. Rooks and Grey Herons, for instance, need fairly tall trees to nest in, but the habitat is defined by the adjacent farmland or ponds and ditches where they feed.

Any extra information on habitat (e.g. species of livestock, dominant crops) is valuable and should be entered in the ‘general comments’ box at the end of the form.

Please feel free to contact the Atlas Coordinator for advice if you have difficulty with recording habitats.

Access to land
Before entering any land away from public rights of way, please ensure that you have the owner’s permission to do so. The ‘letter of introduction’ provided can be used as an aid to obtaining permission and indeed many landowners, farmers, etc. will be interested in the survey and can often provide valuable local knowledge and data. In case of difficulty, your Area Coordinator or the Atlas Coordinator may be able to help.

We have received valuable assistance from the Cheshire County Council Public Rights of Way Unit. In return they have asked us to inform them of any footpaths that are blocked or otherwise inaccessible.  If you find one, please contact David Cogger with the grid reference. Any such footpaths in the local authorities of Halton, Warrington and Wirral should also be reported and will be passed on to them.

All surveyors should be aware that, even during the breeding season, extremes of hot or cold weather can occur. Such conditions are best avoided for fieldwork, as they are not usually the best for finding birds, and can present a hazard to the unwary. You are advised to check a local weather forecast before undertaking fieldwork; always wear appropriate footwear and clothing, including a hat and sunscreen; and take a supply of food and drink with you. When visiting remote areas always tell someone where you are going and how long you are likely to be away. Stick to your advised route wherever possible. If you have a mobile ’phone, take it with you.

Abundance measurement
An important additional element of the Cheshire and Wirral Atlas will be measuring the abundance of birds. This involves making accurate, timed counts in a number of randomly selected tetrads. If you are interested in volunteering for this aspect of the project, please contact the Atlas Coordinator.

Record Forms
Paper record forms have been included with these instructions, but if you require further copies please contact David Cogger (or simply photocopy them). However, we urge you to send in your records electronically if at all possible, either on a floppy disc, or preferably via e-mail or via the Atlas website. To enable this we will be e-mailing you (if we already have your e-mail address) with electronic record forms. If you need further advice regarding electronic submission please e-mail:

Finally …
This survey is a chance not only to get to know the birds of an area much better, and probably to come up with some surprises, but also to contribute to a major project that will see your work published and put to good use for conservation. We hope that you enjoy it. Please let us know how you get on. We shall be producing occasional bulletins on the Atlas, and articles or anecdotes about your tetrad surveying will be very welcome.

Please complete your Atlas Survey Record Cards and return to your Area Coordinator (given on the enclosed list) by 31st July each year (for records on paper), or e-mail your records to by 31st August.