Michigan
Songbird Protection Coalition
Sandhill Crane Population Status
The sandhill crane has been a bird in crisis since the pioneer settlement of Michigan. The history of cranes in the state is marked by episodes of cruelty and indifference: human-caused injuries like recreational hunting, as well as the conversion of vast wetland habitats to agricultural use. Because of this, sandhill cranes have suffered both in the significant reduction in geographic distribution and their population numbers. Without traditional non-game status protection, the effects of local, regional, and national "human use" activities will continue to impact this vulnerable species during times of decline and also recovery.
The Eastern Population (EP) of sandhill cranes (Grus Canadensis) has been in recovery after approaching near extirpation in the late 1800s (Walkinshaw 1949, 1973; Leopold 1949). A population bottleneck crisis in the early 1900s reduced the EP to fewer than 50 breeding pairs in the Great Lakes Region of Wisconsin, Michigan, Minnesota and Ontario (US Fish and Wildlife Service, et al.).
Since the signing of the Migratory Bird Treaty Act in 1916 (i.e., closure of hunting in 1918), sandhill cranes have been in a slow recovery, and only just recently, the EP is thought to be achieving a relatively stable status. However, much is still not known or understood about the sandhill crane due to lack of research and inconsistent research standards. The failure to use principles of sound science to determine population indices with any degree of certainty, as well as complications caused by the genetic isolation of the still-recovering fragmented populations (each with their own unique genetic clusters), yield data difficult to analyze or compare.
Several surveys and population indices exist attempting to monitor the EP sandhill crane numbers as a whole, as well as the number of sandhill cranes in Michigan. Unfortunately, long-term population survey studies cannot be relied upon or be considered useful because they are not consistent with scientific research standards needing to be specific to the sandhill crane. Population studies are tagged in status reports as having low-precision population estimates, with some studies even noted as introducing bias. As a result, even long-term surveys by the USFWS have had to be excluded from analysis by biologists due to significant inconsistencies (Michigan Department of Natural Resources).
A recent two year survey funded by the Michigan Nongame Wildlife Fund confirmed 805 breeding pair statewide (Source: Michigan DNR). Most breeding pairs in the Lower Peninsula were found in a six county area near Jackson and Ann Arbor, while highest concentrations in the Upper Peninsula occurred in the eastern counties.
In conclusion, there simply are no reliable or consistent long-term population status reports available and there is no accurate estimate for the still-fragmented and recovering sandhill crane population in Michigan. Scientific studies that follow strict protocol are needed to provide reliable data that can be used in serious research and analysis necessary to ensure the survival of this magnificent bird.
Article sources, including but not limited to: USFWS, Michigan DNR, Michigan Nongame Wildlife Fund, Wisconsin DNR, Great Lakes Echo, Ohio DNR, The Journal of Wildlife Management, Cranes: A Natural History of a Bird in Crisis by Janice M. Hughes.