1978

Between 200 and 400 waterfowl (0.2-0.4 percent of maximum number present) were killed each fall, 1973-75, by colliding with high-voltage transmission lines that cross the slag pit (32ha of water)at the Kincaid Power Plantand adjacent Lake Sangchris(872 ha of water),central Illinois. Mallards(Anasplatyrhynchos) constituted 37 percent of the victims, blue-winged teals (A. discors) 17 percent, and American coots (Fulica americana) 25 percent. Blue-winged teals were most vulnerable to collisions (0.549 casualty per 1,000 bird-days of use of the slag pit) and mallards least vulnerable (0.026). Factors contibuting to frequency of collisions were (1) number of waterfowl present,(2)weather conditions and visibility, (3)species composition or behavior of birds, (4) disturbance,and (5) familiarity of birds with the area. Power lines should not be built over water unless alternate routes do not exist; lines should not cross areas where waterfowl concentrate;and visibility of lines in problem areas should be enhanced.