BEHAVIOR OF SANDHILL CRANES NEAR POWER LINES MARKED WITH YELLOW AVIATION BALLS

The principal known cause of mortality for wild whooping cranes (Grus americana) is collision with powerlines. Methods to minimize powerline collisions will contribute to the species\u27 long term recovery. We studied the flight behavior of sandhill cranes (G. canadensis) near powerlines marked with yellow aviation balls near the Platte River, Nebraska, in 1988-90. An age ratio of 24 juveniles:76 adults of 84 carcasses found under powerlines was significantly different from typical population ratios of 12: 88 for this species. Two-way contingency table analysis of crane flight behavior data indicated that cranes avoided markers (P \u3c 0.(01), reducing the potential for collision. Proximity ofpowerlines to habitats used by cranes (P \u3c 0.001), wind speed (P \u3c 0.05), and age of bird (P \u3c 0.(01) were important factors contributing to crane collisions with powerlines in Nebraska. Details are available in Wildl. Soc. Bull. 19(4):442-449