Songbird Protection Coalition
Sandhill Cranes and Human Conflict
The Sandhill crane was nearly wiped out in the 1800s by human hunting pressure and habitat conversion to human-use activities. Wetlands cover about 15 percent of Michigan and about one-half of the State's wetlands have been converted to other uses, primarily agriculture. The U.S. Environmental Protection Agency has oversight of the State wetlands protection program, which has protected the remaining habitat for cranes and other wildlife species (USGS).
The sandhill crane's natural tendency to feed on plant tubers sometimes creates temporary conflicts with two specific types of crops - primarily corn, and, occasionally, winter wheat - when initially planted in the spring. The most commonly reported issue from farmers is the feeding by sandhill cranes on recently planted corn seed near prime wetland habitats. Cranes will probe the ground and remove individual kernels within the first few weeks after planting. They can continue to supplement their diet on the germinating seed until the corn plant reaches about 4 inches in height.
Most agricultural complaints result from large family groups of sandhill cranes feeding on newly planted corn fields within 3/4 of a mile from wetlands or ponds. While agricultural conflict by cranes is not widespread, it can impact germinating corn fields near farms adjacent to wetland areas. For farms near prime habitat, there are several solutions to consider:
Documentation is lacking to determine whether hunting or other lethal means of removing sandhill cranes reduces crop damage (USDA).
While complaints about crop depredation are sometimes cited as justification for opening a sport hunting season on sandhill cranes, it is widely understood by wildlife biologists and state and federal agencies that such a hunting season would not provide direct assistance to areas impacted by spring crop damage (Ad Hoc Eastern Population Sandhill Crane Committee, 2010; et al.).
According to the USDA Census of Agriculture, 2.4 million all-purpose acres are planted with corn in Michigan. At its peak issuance in Michigan in 2013 and 2014, only 85 depredation permits were issued to address agricultural conflicts with sandhill cranes. In 2015, only 74 sandhill crane crop depredation permits were issued in Michigan - a decrease of 13 percent from the two years previous (MI DNR). IT IS IMPORTANT TO NOTE: Under a depredation permit issued by the USDA, "Any birds killed are to be disposed of in accordance of the permit and are not to be used for human consumption."
However, even the necessity for depredation permits can be effectively avoided with the use of anthroqionone-treated seed, at an affordable application cost of only 5 dollars per acre. Avipel Shield is a non-lethal repellent with active ingredient anthraquinone (AQ), a non-toxic compound naturally produced by plants to protect their fruit from being eaten before ripening. Sandhill cranes find AQ-treated seed distasteful and quickly learn to avoid it. Presently, it is the most effective long-term solution for corn farms adjacent to prime nesting habitats. Avipel liquid is a seed treatment used alone or mixed with pesticides, and thus must be applied prior to planting. Avipel dry is a hopper-box treatment that can be added at the time of planting. No federal permit is required to use non-lethal practices to mitigate conflicts with sandhill cranes and no additional time management needs are required. The product's application is known to pay for itself with higher harvest yields - of several bird and mammal species. It is the best solution that delivers documented results.
It is important to note, however, that sandhill crane presence in various crop fields does not necessarily indicate conflict or damage. For example, sandhill cranes are often found feeding in soybean fields, but their feeding on the actual soybean plants or seeds has not been documented. In this situation, sandhill cranes provide a clear benefit to the farmer by eating insects and other crop pests. Addtionally, although sandhill cranes avoid AQ-treated corn, they will often remain in the field to feed on pest insects such as white grubs and caterpillars. Thus, the use of AQ allows cranes to access critical food items in cultivated fields, such as waste grain and harmful insects, which provides a significant benefit to farmers and can impact higher yields of harvested corn (Source: The International Crane Foundation).
Source, including but not limited to: Michigan State University Extension, University of Wisconsin Extension, United States Department of Agriculture, Arkion Life Sciences, Michigan Department of Natural Resources, Ad Hoc Eastern Population Sandhill Crane Committee, International Crane Foundation, United States Geological Survey.