SUMMER BEHAVIOR AND MORTALITY OF DARK-RUMPED PETRELS AND NEWELLS SHEARWATERS AT POWER-LINES ON KAUAI

We studied crossing distances, behavior, and mortality of Dark-rumped Petrels (Pterodroma phaeopygia sandwichensis) and Newell's Shearwaters (Puffinus auricularis newelli) around a power line on Kauai, Hawaii, in thr summers of 1993-1994. Both species crossed this power line at s ignificantly smaller distances in the morning (while flying to sea) th an in the evening (while flying inland). In the morning, birds flew at higher flight altitudes at locations similar to 800 m inland than at nearby coastal locations. Approximately 5% of each species exhibited b ehavioral responses while crossing power lines; only Dark-rumped Petre ls exhibited a significantly higher frequency of response in the morni ng than in the evening, however. Most of the Newell's Shearwaters that were killed ill summer collided with power lines while on their way t o sea, primarily at power lines <100 m from the coast and in valleys. Approximately 20% of the shearwaters killed were adults; most of the r emainder were subadult, nonbreeding birds.