Northern Prairie Wildlife Research Center
Project Scope and Design
One of the problems faced by breeding bird atlas organizers, especially in states like South Dakota with small populations, is the shortage of observers. Overcoming this problem requires dividing the state into a small number of large blocks, or sampling from among smaller blocks.
In South Dakota data were collected from 124 stratified random (3 mile x 3 mile size) blocks throughout the state. In addition, 118 "special blocks" (3 mile x 3 mile) - nominated as good examples of native habitat, and/or known occurrence of special interest species were surveyed, as were 173 various sized, managed areas (e.g., state and national parks, waterfowl production areas, game production areas, etc.). All designated blocks and areas were delineated on county maps for use by atlasers.
In addition to observations from designated blocks and areas, observations of "special interest" species were also recorded outside these blocks and areas and called Casual Observations All Casual Observations were located by Township, Range and Section, as determined from the county maps.
Coverage of Blocks and Areas
The South Dakota Breeding Bird Atlas Project began in 1988 and continued though the 1993 nesting season. However 96% of random block observations were reported in the first 5 years. The sixth year, 1993, was primarily needed to complete the inventory of designated managed areas and search for nests of "special interest" species.
Observers were encouraged to survey all of the habitats available in all blocks and areas visited, however random blocks were the top priority for coverage. The most intensive efforts and greatest number of repeat visits were made to the random blocks - most were visited 3 or more times, plus at least one nocturnal trip in early spring to find owls, with a total time for most of 20+ hours. Only 2 random blocks were visited just once.
The goal in the random blocks was complete coverage (i.e., no new species found during a repeat visit). This goal was met in several blocks, but in most cases at least 1 new species was found on the last visit. Overall coverage of species in random blocks was estimated at 90+% of species expected. Annual variations in habitat conditions, especially wetlands and grasslands made it likely that even "experienced birders" would miss some species unless each block was visited each year of the project, which was not practical.
Managed Areas were the next priority for observer time, especially the USFWS National Wildlife Refuges and Waterfowl Production Areas designated under the terms of an agreement between the USFWS and the SDBBA Project for inventory in 1992 and 1993. These USFWS Managed Areas received intensive coverage in these 2 years and 90+% of expected species present were probably reported, based on comparison with some current refuge checklists.
Special blocks were the lowest priority for observers, and coverage of all species in these blocks was not consistent. However, finding special interest species was the primary focus in these blocks rather than complete coverage of all species. Assessment of coverage progress was made after each field season. Atlasers were asked to visit specific blocks and areas the following year in an attempt to provide more uniform coverage.
Atlasing Procedures and Data Collection
Volunteer atlasers were given an instruction handbook, data sheets for recording observations, and county maps with all of the designated atlas blocks and areas delineated.
In brief, the instructions were: Go to a designated block or area and record location, date, bird species seen and their breeding behavior; record each species only once, at the highest level of breeding evidence observed during the visit. Please include habitat information, as well as an abundance estimate if in a random block. Do not attempt to cover the entire block, but sample all habitats present.
Breeding Behavior Categories
The SDBBA database includes only the highest breeding behavior evidence reported for each species in each block or area where a species was found. A species has only one breeding status record in any particular block or area (i.e., Observed, Possible, Probable or Confirmed). If duplicate records were received the one with the earliest date was entered.
EXAMPLES OF BREEDING BEHAVIOR:
Observed = O = Species observed during its breeding season, but no other evidence of breeding....Not in suitable habitat.
Possible = PO = Species observed in suitable habitat during its breeding season....Singing male in suitable habitat.
Probable = PR = Pair observed in suitable habitat....Defense of territory (chasing of birds of same species)....Courtship behavior....Agitated behavior or anxiety calls by adult.
Confirmed = CO = Carrying nesting materials....Nest building....Distraction display....Flightless young....Adult observed on a nest or entering or leaving a site in circumstances indicating an occupied nest.....Adult carrying food for the young....Adult feeding recently fledged young out of the nest....Adult carrying fecal sac....Nest with eggs....Nest with young.