Atlas fieldwork - a few tips

OK, so you've agreed to take on a tetrad (2-km x 2-km square) for the new Bedfordshire Breeding Bird Atlas. What next?

The first job, of course, is to peruse a map and work out the exact limits of 'your' tetrad. Look for streams, rivers, lakes, ponds, woodland and any other features that may give a hint of the variety of different bird habitats within the area. This will make it much simpler to go to the best places on your first recce trip. Obviously, you can't go everywhere, and it's far easier to sample the birds on a river by watching from the bridges than to trudge the whole length of the riverbank (though you may choose to do so later, of course). Woods and parkland are likely to be private, and it is ESSENTIAL to obtain permission to survey these areas. It is worth making direct contact with the owner, as he is also likely to be able to give valuable information about birds such as Barn Owl, Little Owl, Woodcock and Common Buzzard, and even Pied Wagtail or Spotted Flycatcher nests if you are lucky.

If your tetrad contains no conifer wood, it's worthwhile trying a churchyard, where there may be Coal Tits or Goldcrests frequenting the yew trees, and this is also a favourite habitat for Spotted Flycatchers in our county.

It is not necessary to spend time searching for nests. This is an exceedingly time-consuming occupation and is seldom necessary. It is much easier to obtain breeding evidence by watching for adults carrying nesting material, carrying food for their nestlings or fledglings, or carrying faecal sacs away from the nest. In reasonable weather conditions (calm and dry), it is often possible to find evidence for 40 or 50 species in a tetrad in six hours or so. It is usually sensible to move on to another tetrad (or give up for the day) if you have spent, say, an hour finding just one or two new species. Come back another day, later in the season, or at another time of day. At least one visit is needed at dusk and the early part of the night for Woodcock, owls and other crepuscular and nocturnal species, and some birds (such as Tawny Owl, Mistle Thrush and Crossbill) are much easier to find in the early part of the year, whereas others (such as Nightingale) have to be targeted during their short song season, and a few species (such as Yellowhammer) may not start to nest until after most other species have already reared their broods. Visits late in the season (end of June and July) can be especially productive for proving breeding, since newly fledged juveniles can be much easier to spot than their secretive parents (but beware records close to the edge of a tetrad, in case juveniles have wandered from one square to another).

How many visits are needed to cover 'your' tetrad? Well, one is better than none, but the minimum should perhaps be three: one early in the season (say, mid April, one late in the season (say, late June) and one at dusk and the first part of the night. Of course, the more the better. If you live in or near your tetrad you may pay a whole string of visits each year for the duration of the project, but if you have the time available, it is more productive to take on several tetrads than to 'blitz' one tetrad time and again, and let's face it - it's more fun to start again in a new tetrad and find lots of new records.

How long should a visit last? Again, one hour is better than none, but four to six hours is probably the most efficient, though two hours in the early morning and another two hours in the early evening would be better than six or even eight hours in the middle of the day.

Our Bedfordshire atlas aims to discover as many species as possible in each tetrad, so there are no set 'rules' about where or when to go, no transects to follow and no mapping to be done in the field. In each tetrad, you should aim to visit every habitat in order to try to find every species of bird. This does not mean that every part of the tetrad must be visited, just some typical or the best examples of each habitat.

It's great fun, and exceedingly worthwhile. You will be recording today's history for the benefit of posterity. Let's put the birds of Bedfordshire on the map!

Tim Sharrock, on behalf of the Records & Research Committee