Ecology of Non-breeding Wisconsin Sandhill Cranes, with Emphasis on Crop Damage and Migration

Abstract

Studies of non-breeding greater sandhill cranes (Grus canadensis tabida), their movements, habitat use, migration, wintering grounds, and involvement in crop damage, were conducted in Wisconsin, Indiana, and Florida from April 1976 through November 1977. Fifty-eight cranes were captured and color-marked in central Wisconsin and another 10 non-breeders were fitted with radio transmitters. Radio-tagged cranes inhabited minimum home ranges of 774 to 3,691 ha during 6-18 week periods from April through September. At least 1 nonbreeder spent consecutive summers at locations more than 56 km apart. Non-breeding birds are responsible for nearly all the sandhill crane crop damage occurring in Wisconsin. In a majority of cases the damage is caused by 10 or fewer cranes, and in many areas damages are recurrent from year to year. Tests using the chemical methiocarb as a repellent to cranes in sprouting corn (Zea mays) were inconclusive. Acetylene exploders are the most effective method of control presently in use. Visits by landowners to fields to scare cranes are effective and should be encouraged when practical. Lure crops may be of value in areas that experience recurrent damage and are located near wetlands with large numbers of cranes. Wisconsin Department of Natural Resources personnel should continue to evaluate crane damage complaints critically and as soon as possible after damage occurs. Eleven major sandhill crane staging areas in Wisconsin supported a peak fall population of over 3,500 cranes in 1977. Five of these areas were in private ownership. Sandhill cranes from the Mead Wildlife Area in central Wisconsin moved southwestward to the Sandhill Wildlife Area before leaving Wisconsin in the fall, and cranes from Shawano County in northeast Wisconsin moved to staging areas in southeast-central Wisconsin. The fall migration of cranes from Wisconsin is related to the opening of the waterfowl hunting season. Cranes in southeast-central Wisconsin, where roosting marshes are subjected to heavy hunting pressure, leave the state up to 6 weeks earlier than cranes with undisturbed roosts at the Necedah National Wildlife Refuge and the Sandhill Wildlife Area. More than 80 percent of the sandhill cranes color-marked or radio-tagged in central and northeastern Wisconsin in 1977 were observed at the Jasper-Pulaski Wildlife Area, Indiana, during the fall migration. Some stayed less than 1 week, others for 7 weeks or longer. Cranes from southeast-central Wisconsin staging areas arrived at Jasper-Pulaski earlier and stayed for longer periods than cranes from west-central Wisconsin. Variations in the "typical" activity patterns of cranes at Jasper-Pulaski are due to the changing influences of weather, season, disturbances to the birds, farming practices, and land-use patterns. Over 4,500 wintering greater sandhill cranes were accounted for in central Florida and southern Georgia during the winter of 1976-77. Eight cranes color-marked or radio-tagged in central Wisconsin since 1973 were reported from 5 locations in central, eastern, and western Florida during the winters of 1976-77 and 1977-78.