Delineating sandhill crane populations in Minnesota

Principal Investigators: David E. Andersen and John Fieberg.

M.S. Student: David Wolfson.

Sandhill cranes (Grus canadensis) are considered to be an important part of Minnesota’s natural heritage, and although they have expanded their breeding range in Minnesota, they remain a species of management concern. Minnesota supports 2 populations of sandhill cranes– the Mid-continent Population that breeds and migrates through northwestern Minnesota, and the Eastern Population that breeds and migrates throughout much of the remainder of the state. Minnesota initiated a sandhill crane hunting season on Mid-continent Population cranes in 2010, and Eastern Population cranes are currently hunted in Kentucky and Tennessee. Several other eastern states are currently considering initiating sandhill crane hunting seasons on Eastern Population cranes, and Mid-continent Population cranes are currently hunted in much of the central U.S. and Canada. Current information on population distribution and migration patterns of sandhill cranes that breed in Minnesota is insufficient for projecting the impact of current and future hunting seasons, and for making informed management decisions in Minnesota. In addition, sandhill crane crop depredation complaints have increased exponentially over the last 10 years in some locations in Minnesota and complaints will continue to grow with increasing crane populations. Wildlife managers in the state require a better understanding of crane movements and what cranes (e.g., breeders or non-breeders) are responsible for the damage to address this growing problem.
A 2012 survey estimated there were 7,200 Mid-continent Population sandhill cranes in northwestern Minnesota during the breeding season. How many Eastern Population sandhill cranes breed in Minnesota is not known; recent surveys have tallied > 75,000 Eastern Population cranes on fall staging areas. The size of the Eastern Population of sandhill cranes has increased significantly in the past 15-20 years, and Eastern Population sandhill cranes have expanded their breeding range during that period in Minnesota. As crane numbers increase, conflicts between cranes and agriculture will also increase, and there will be additional interest in hunting cranes more broadly across Minnesota and the eastern U.S. However, management options in Minnesota are currently limited because the boundary between Mid-continent Population and Eastern Population cranes is not clearly delineated. Furthermore, additional information concerning how and where cranes depredate crops and how cranes use habitat at local and landscape scales is required to effectively manage sandhill cranes in Minnesota. By using cutting-edge GPS-cell transmitters (or satellite PTTs in the event that GPS-cell transmitter technology is insufficient), we aim to help fill in these important information gaps. Specifically, we propose to address the following goals and objectives:

  1. Delineate the boundary between Mid-continent and Eastern Population sandhill cranes in Minnesota, allowing these populations to be more effectively managed as separate units.
  2. Determine spatial patterns in the use of agricultural crops, grazed and ungrazed grasslands, and wetland habitats by cranes, thereby improving our ability to determine appropriate management actions, including steps necessary to address depredation issues.
  3. Evaluate year-round movement patterns (e.g., migration) and survival of Minnesota sandhill cranes.