For many birdwatchers, the summer months are distinctly anti-climatic. Birding excitement begins in mid-March with the arrival of the first red-winged blackbirds and builds steadily through the raptors and waterfowl of April to the frenzied peak of May's returning warblers. By the end of May, however, migration activity has slowed down-and so have a lot of birders.

Starting in 1986, however, summer is going to be different for hundreds of birders in the Maritimes. In fact, the latest avian pastime reaches its zenith in June and July, providing a two-month extension to the birding season. A new project, the Maritimes Breeding Bird Atlas, is bringing nesting into the limelight by focusing attention on the reproductive cycle of birds, a process which has gone relatively unnoticed among amateur birdwatchers in the pat.

The end product of a breeding birds atlas project is a book of maps. Each species of bird which breeds in the Maritimes will have a map showing its distribution. Although many field guides contain range maps with information similar to this, they are usually compiled from scattered records and from "best guesses" by the author. An atlas map is composed of evidence recorded by volunteers specifically looking for breeding in their area. This means that the maps in an atlas are much more accurate than those in a field guide and thus have a great deal of scientific merit.

While a breeding bird atlas is new for the Maritimes, the concept itself has existed for several years. The first atlas project was undertaken in 1968 in Great Britain and was published in 1976. Since then, the atlas egg has hatched in many countries, including Canada and the U.S. In North America there are 38 atlas projects in various stages of completion. These include Ontario (1981-1985) and Quebec (1984-1988) with projects being organized in some of the Western provinces.

The data collected for the breeding bird atlas have many conservation applications. After determining which birds are where, it is possible to pinpoint areas that art ecologically import and meriting high priority for preservation. It also shows the distribution of rare, threatened and endangered species. Since atlas methods are standardized, the procedure may be repeated at some point in the future so that researchers can detect any changes in bird distribution. Equally important, an atlas is an excellent way for participants to improve their knowledge of the natural history of birds.

To obtain records which are evenly spread across the Maritimes rather than clustered around population centres, observers are asked to work within the bounds of a grid cell. Canadian topographic maps have the Universal transverse Mercator (UTM) grid printed on them. This grid delineates squares, 10 km to a side, each with a unique number/letter code for identification. This is ideal for atlas purposes as it provides a standard grid readily available to volunteers, and the data from each square can be computerized using the UTM square codes. There are roughly 1600 of these 10km x 10km squares in New Brunswick, Nova Scotia and Prince Edward Island - quite a task to get a birder in each one!

The initial goal of the Maritimes atlas is to completely cover one quarter of these squares over five seasons (1986-1990). An atlas volunteer completing their square in less time would have the opportunity to take on a new one and thus give us more than 25% coverage.

Once a volunteer has located their square, the first step is to determine the different habitat types present. Driving through the square or exploring it on foot will make these differences apparent. Surveying a sample of each of the various habitats will reveal most bird species to be expected in a square while eliminating the need to explore the whole area. this will save considerable effort in squares with relatively uniform habitat, particularly if the road access is poor.

A square is completely surveyed when two criteria are met: at least 20 hours have been spent in the square over the 5-year period, and breeding evidence has been recorded for 75% of the species expected to breed in the square. the time factor is an estimate based on the results from previous atlas projects. In general, it will take an experienced observer 20 hours at the height of the breeding season to meet the expected species totals.

The number of potential species is estimated using a formula which predicts a given number of species for each different type of habitat. The British found that even a top-notch birder could not find every breeding species in a square in 100 hours. These figures are applied as a guideline to help volunteers know when to devote most of their energy to a new square.

The fun part, however, is looking for breeding evidence. Nests themselves are often difficult to find, as they can be built high up in the tree canopy of hidden in the center of shrubs. Fortunately, birds indicate breeding activity through their behaviour, so it is not necessary to find a nest in order to record evidence. The males of many species sing to attract mates, and by identifying the species a birder can record evidence for the "Possible" category. "Probable" records, the next level of evidence, constitute observations such as a male-female pair of birds, courtship displays, and agitated behaviour.

The highest category is for "Confirmed" records like birds gathering materials for nest-building, fledged young birds, sightings of adults carrying food for the young, and, of course, finding a nest containing eggs or young. because confirmed records have the highest degree of certainty, atlas volunteers are encouraged to collect evidence in this category for as many species as possible.

There are a few tricks one can employ to confirm breeding, but one of the easiest is to visit a square in the latter part of the season to look for adults carrying food.

Besides breeding evidence the birders are also interested in abundance. It would be virtually impossible to actually count numbers of a species, but it is relatively simple to make an estimate. The categories for abundance are based on a logarithmic scale (e.g. 1 pair, 2 -10 pairs, 11 - 100 pairs, etc., up to more than 10,000 pairs). Estimates are made by assessing the amount of suitable nesting habitat for each species within the 10 km square. Having a general idea of the abundance of a species will be particularly useful as a reference in the future. Knowing that a breeding colony has declined from 101 - 1000 pairs to 2 - 10 pairs provides more information about the status of the species than merely knowing that it is still there.

The completed atlas will provide the first comprehensive look at the status of breeding birds in the Maritimes. Amateur naturalists can make a tremendous contribution to the base of scientific knowledge. Several federal and provincial government agencies, including the N.S. Department of Lands and Forests, are providing financial and/or logistical support to the atlas.

Nonetheless present - and likely future - restraints on government spending mean that more of the responsibility for monitoring environmental changes may rest with interested volunteers. It isn't necessary to be an expert in order to provide useful information. Anyone with a moderate ability to identify birds is welcome to participate. Keep your binoculars out this summer; spring migration is only the opening act.