Procedures - Rare animal surveys: Breeding birds
Photo copyright Warren Nelson.
The Minnesota Biological Survey (MBS) conducts field surveys for breeding birds primarily from late May through June. For early breeding species, such as Red-shouldered Hawks, surveys may begin as early as April. For other species, such as Loggerhead Shrikes, surveys may extend through July after the young have fledged and are more visible. Survey techniques include the following:
Point counts are the primary survey method employed by MBS. At several points within a given habitat, all birds seen or heard singing during a 5-minute interval are identified and evidence of breeding or nesting is recorded. Point counts are conducted from sunrise to 9:30 am, during suitable weather conditions.
Tape-recorded playbacks of bird calls are played to elicit responses by resident birds. Depending on the targeted bird species, taped calls of territorial male birds or avian predators are played through an amplified speaker. All species reacting to the call are recorded and their behavior noted.
Photo by G. Nordquist
Road surveys are conducted to locate large or conspicuous birds associated with open country, such as agricultural areas and grasslands. Roads by selected sites are traveled, stopping every half mile to scan the area for birds.
Other observations, such as road-killed birds, nests, and incidental observations are recorded when encountered.