Recruitment of fieldworkers
Recruitment was started by placing notices in Bird News, the CAWOS newsletter, and by announcements at indoor meetings. The call was taken up by many of the county’s local natural history and ornithological societies and RSPB groups, and several members from CAWOS were invited to visit groups to seek out new recruits. Notices were placed in the local press, in local and national birdwatching publications, and in hides and visitor centres throughout the recording area, and a website was created. CAWOS members and birdwatchers covering BTO surveys were often asked to cover tetrads in which they either lived or surveyed.
Recruitment was aided when the Public Rights of Way Unit of Cheshire County Council provided us with laminated maps of the recording area; these were marked with dots to indicate when coverage of a tetrad was complete and, when displayed at many indoor meetings, spurred more volunteers to help to fill the blank areas. In return we helped the Unit by informing them of any footpaths which had been blocked or were difficult of access. It was emphasised that fieldworkers must obtain permission from landowners for access to private land, and a letter was written by the Atlas Coordinator to facilitate these approaches. In practice, almost all landowners agreed to fieldworkers’ requests and in many cases showed considerable interest in the project and provided extra information themselves.
Over 360 birdwatchers sent in records for the Atlas, for some of whom this was their first experience of systematic bird recording. Contributors were divided almost equally between CAWOS members and non-members. The former covered two-thirds of the tetrads, but we were keen to stress throughout that all records were valued, from whatever source.
We had hoped to be able to solicit records from a wider community, including farmers, wildfowlers, schools and the general public, with information about nocturnal species hoped for moth, bat and badger groups; but, apart from a few instances of personal contacts, procuring such data proved beyond the resources of our amateur project.
Training
After the initial recruitment phase, over 70 prospective participants attended a one-day meeting on 28 February 2004, just before the start of the project, for training especially in the categories of breeding status and habitat coding. We were able to obtain from the BTO cassette tapes or CDs for those unsure of bird songs. Notes and discussion of recording techniques and data submission protocols were included in the Atlas newsletters and in a ‘Frequently Asked Questions’ (FAQ) section on the Atlas website, and the Atlas Coordinator provided advice in person, by telephone or by e-mail to many fieldworkers, especially in the first year or so.
Area coordinators
An important part of the organisation was the Area Coordinators, who volunteered to cover, typically, a 10x10 km square, containing 25 tetrads, but ranging from two tetrads, in areas at the west and east of the county, to several areas where a coordinator took responsibility for several 10-km squares. Their function was to act as an intermediate level between the Atlas Coordinator and the individual fieldworker, helping with the recruitment of volunteers, keeping in touch with them and giving help where necessary; ensuring full coverage and checking that fieldwork was being done and records submitted; overseeing the data being sent in, including examining for consistency and acting as the first level of quality control. The best of the Area Coordinators added real value to the process, encouraging and supporting fieldworkers in their area, some of them holding discussion meetings with their surveyors, sorting out many small problems and contributing their local knowledge, generally doing more than expected. On the other hand, some were worse than useless, failing to fulfill what they had agreed, sitting on records for long periods, holding up the project and making lots of extra work for others, including causing some tetrads to be surveyed twice where they failed to keep in touch with their fieldworkers or to respond to requests to submit data.
Instructions and Guidance
Considerable effort was expended to try to make the fieldwork and the recording as straightforward as possible, especially as we recognised that some of those taking part were not used to systematic bird recording. Copies of the Instructions and Guidance notes for the breeding and wintering parts of the survey are included at the end of this Appendix. These were sent to each registered participant, along with a map of their tetrad.
Effort
We asked observers to record the dates on which they recorded in their tetrad, and the approximate amount of time that they spent on fieldwork. It is recognised that this is not a precise figure, especially for the one-third of fieldworkers who lived or worked in a tetrad that they were surveying.
The mean figures were 30 hours per tetrad for the breeding survey and 18.3 hours per tetrad for winter atlas work, a total of over 32,500 hours. This does not include supplementary records, nor time spent in fieldwork in other organisations from whom we obtained records, or the other sources of recording (such as WeBS, BBS, heronries counts and so on) whose records and results were incorporated in the Atlas.
We thus estimate that about 50,000 hours of fieldwork were expended on this project.
In addition, countless hours indoors were committed by the Atlas Coordinator, other members of the Steering Group, Area Coordinators, the database manager, artists, photographers and numerous other people involved in this project.
Efficiency of coverage
Given a finite number of observers and finite time available, there is a clear trade-off between continuing to visit a tetrad to find every species and moving on to cover more tetrads. Some dedicated fieldworkers felt that they wanted to persevere in ‘their’ tetrad and try to find every species present and, in the breeding season, to try to prove breeding for all of them if possible. After investment of a few hours’ of effort, however, the exact amount depending on the diversity of habitat, the experience of the observer, the stage of the season, and so on, it became increasingly difficult to add extra species and the best option, for the good of the Atlas project as a whole, was to move on to cover a different tetrad. Some observers were reluctant to do that when they knew that there were species probably in the tetrad that they had not yet found, and many surveyors enjoyed getting to know better a tetrad that they had not previously visited. Some other atlases have given fieldworkers guidance on what would be considered a reasonable level of coverage – the 2nd Pennsylvania Breeding Bird Atlas, for instance, advised surveyors that 75% of the expected number of species was a satisfactory result – but we did not set any targets.
There is clearly an element of uneven coverage from one tetrad to another depending on factors such as the observer’s familiarity with the area, their tenacity and temperament. In one or two areas the Area Coordinator was more assiduous than most in urging fieldworkers towards ‘complete’ coverage but, in general, there were not wide variations across the county and we can be reasonably confident that most of the differences seen in the maps are real differences in bird distributions rather than the effects of varying effort or competence.
During this Atlas we had an interesting experiment in efficiency of coverage. Two very experienced observers, who covered more than 10 tetrads each, inadvertently both surveyed two tetrads in the 2006 breeding season, independently of each other, this only being realised months after the end of the season. One tetrad received about 6 and 10 hours of effort from the two surveyors and the other about 8 and 12 hours respectively. Out of the total number of species found, both observers recorded 75% of them; of the remaining one quarter of species, each fieldworker found some birds that were missed by the other, roughly in proportion to the time spent surveying.
Our winter instructions called for observers to ‘Please feel free to visit your chosen tetrad as often as you like and to spend as long as you want on surveying. The minimum to achieve reasonable coverage is to visit twice, once from 16th November to the end of December, and once from 1st January to the end of February. The two dates should be at least four weeks apart. … 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. To stand a reasonable chance of finding all species, each visit should last at least two hours.’
This advice was similar to that for the Breeding Bird Survey, and has recently been validated by pilot fieldwork for the BTO Bird Atlas 2007-11 (Gillings 2008). For a wide variety of species, the pilot study showed that, given a finite quantity of field effort, to maximise the number of species found and to minimise error in relative abundance estimates, it is better to distribute survey effort by visiting more tetrads for a shorter period than vice versa.
