Nocturnal and Diurnal Foraging Activity of Hawaiian Albatrosses Detected With a New Immersion Monitor

We used a new immersion monitor to study the foraging movements of two species of albatrosses that nest in the Hawaiian Islands. The monitors showed that breeding male Black-footed Albatrosses (Phoebastria nigripes) land on the water more frequently during the day than at night. Breeding male Laysan Albatross (Phoebastria immutabilis) behavior was more variable and also showed a diurnal bias. We found no evidence of a nocturnal foraging bias in either species; in particular, these species do not seem to be limited to live capture of nocturnally available squid. Such squid may, nonetheless, contribute to the diet as a result of scavenging.