Note that a measurement of Absolute Abundance may only account for a specific segment of a population. For example, if the objective is breeding pairs, separate abundance calculations will have to be made for pairs and for other birds recorded. Similarly, if nests are being surveyed, the result will give nest abundance but will not account for birds in the study area that did not build nests.
Note also that results from these methods can be considered estimates of total abundance only if all biases have been eliminated. If this is not the case, then the survey will measure relative rather than absolute abundance. Biases that can not be eliminated should be measured (usually with more survey effort) so that counts can be corrected.
Recommended method(s): See Tables 2 and 3 for species-specific recommendations.
Observation Stations - Absolute Abundance for all stages of life cycles. It is the preferred method for counting breeding pairs, nests, and broods for all but the most conspicuous waterfowl species (e.g., geese and swans).
Helicopter Surveys - Absolute Abundance for breeding pair counts / brood counts for the most conspicuous species (e.g., loons, geese, swans) and when necessary for dabbling ducks in large, inaccessible areas.
Ground Transects - Absolute Abundance for non-breeding bird counts, particularly where 100% coverage can be achieved from roads or trails.
Boat Transects at sea - Absolute Abundance for detecting non-breeding birds on the ocean and in large wetlands (e.g., lakes or rivers) or along shorelines. Boat transects are suitable for surveying flocks of moulting and wintering sea birds in defined areas (Savard 1982). However, for large and/or dense flocks of birds, boat surveys may yield a count or estimate with a large error.
To achieve absolute abundance, a boat transect must systematically cover an area of interest so as to record all birds or to sample a known proportion of the area. It is most useful in relatively small, well defined areas. If the area being surveyed is along a shoreline, only one transect is required.
Aerial Transects - Absolute abundance for swans: breeding pairs, incubating birds, or broods in open habitat. Transects must have a known width so that densities can be calculated.
Nest Counts - Absolute Abundance for almost all breeding waterbirds (except ducks). Nest Counts may be conducted using chestwaders or a canoe to search for nests of species that nest over water. These counts are also used for surveying upland ducks breeding in open habitat in confined areas.
Aerial Photographs - Absolute Abundance for concentrated non-breeding flocks of large bird species that contrast with their background (swans and B-SNGO).
Mark-resight/recapture - Absolute Abundance for non-breeding birds (swans, geese, and Sandhill Cranes). This method is useful only for very specialized kinds of surveys.
See Tables 2 and 3 for species-specific recommendations. Absolute Abundance can be obtained for all stages of life cycles. It is the preferred method for counting breeding pairs, nests, and broods for all but the most conspicuous waterfowl species (e.g., geese and swans).
The close proximity of an observer to the birds means that ground surveys are the most accurate technique for counting birds, especially breeding birds which are more difficult to detect (because they occur at relatively low densities on wetlands partly covered in emergent vegetation). Therefore, with enough time and effort, ground surveys can be used to obtain estimates of absolute abundance. If absolute abundance is the objective, the observer must be confident that enough stations have been used to obtain either complete coverage or enough samples to enable a reasonably accurate extrapolation to account for birds in the unsampled areas.
*These techniques are also used for relative abundance surveys. Only differences from the relative abundance survey are listed here. For details on how to conduct this type of survey see section 3.4.2.
For each Study Area or wetland: