Every spring, Department of Natural Resources (DNR) staff members and volunteers conduct spring roadside surveys throughout Michigan. During the spring breeding seasons, many different birds and animals are easily detected because of the displays and sounds they make. This makes spring the best time to do wildlife population surveys. Many of these surveys are done from the roadside, where observers are stationed to count the number of individual birds and animals detected. Comparing the results of the survey from year to year helps determine if the population is increasing or decreasing.
The DNR Wildlife Division staff focuses on ruffed grouse and woodcock surveys statewide, sharp-tailed grouse surveys in the eastern Upper Peninsula and mourning dove surveys in southern Michigan. Staff members and volunteers travel the same routes on about the same day each year. This allows population numbers to be monitored from year to year.
Grouse (both ruffed and sharp-tailed) and mourning doves are most active in the morning, so surveys start 30 minutes before sunrise. The driver turns off and exits the vehicle, and listens for the bird he or she is surveying. A male ruffed grouse will “drum” or rapidly beat its wings while standing on logs in order to attract females. The “drumming” starts out slow and increases to the point that it may sound like a two-cycle engine starting. Male sharp-tailed grouse will cluck and make a rattling noise with their tails in a communal dancing ground called a lek.
In the case of mourning doves, the driver is listening for the dove call and counting the number of birds seen. Although doves are not game birds in Michigan, they are hunted in many other states so the Michigan DNR participates in the surveys as part of the nationwide effort to manage the species.
Woodcock surveys are done in a similar manner as the grouse routes, although woodcock exhibit aerial and vocal courtship behavior in the evening, so the survey is conducted near sunset. The exact start time is determined by the cloud cover the evening of the survey. The male woodcock will start to send out calls sounding like “peent” near sunset. Shortly after the “peent” the male woodcock will lift off into the air and fly straight up and circle and chirp before he comes back down.
Spring roadside wildlife surveys, along with hunter cooperator surveys and mail harvest surveys, have helped the DNR to monitor wildlife populations. Data from these three annual surveys can then be compared to determine whether populations are increasing or decreasing. Other surveys are used for other types of birds and animals.
“The surveys we complete help us to monitor population trends throughout Michigan,” said research supervisor Steve Beyer. “We wouldn’t be able to complete all of the surveys we do without the help of volunteers and other organizations.”
The DNR partners with organizations such as the Ruffed Grouse Society, U.S. Fish and Wildlife Service and U.S. Forest Service, as well as many other volunteers and college students, to complete these annual surveys.