BACKGROUND Climate-driven environmental change in the North Pacific has been well documented, with marked effects on the habitat and foraging behavior of marine predators. However, the mechanistic linkages connecting climate-driven changes in behavior to predator populations are not well understood. We evaluated the effects of climate-driven environmental variability on the reproductive success...

cairostris (Cuvier’s beaked whale) and Mesoplodon densirostris (Blainville’s beaked whale). The authors find that both of these species undertake long, deep dives to capture deepwater prey. Diving is highly regular with most deep foraging dives being followed by an extended period of shallow dives and slow travel and resting near the surface. All foraging dives of both species are considerably ...

Air-breathing divers are assumed to have evolved to apportion their time between surface and underwater periods to maximize the benefit gained from diving activities. However, whether they change their time allocation depending on the aim of the dive is still unknown. This may be particularly crucial for 'surfacers' because they dive for various purposes in addition to foraging. In this study, ...

BACKGROUND Free ranging foraging animals can vary their searching intensity in response to the profitability of the environment by modifying their movements. Marine diving animals forage in a three dimensional space and searching intensity can be varied in both the horizontal and vertical planes. Therefore understanding the relationship between the allocation of searching effort in these two sp...

BACKGROUND Optimal foraging theory predicts that animals will tend to maximize foraging success by optimizing search strategies. However, how organisms detect sparsely distributed food resources remains an open question. When targets are sparse and unpredictably distributed, a Lévy strategy should maximize foraging success. By contrast, when resources are abundant and regularly distributed, sim...

cairostris (Cuvier’s beaked whale) and Mesoplodon densirostris (Blainville’s beaked whale). The authors find that both of these species undertake long, deep dives to capture deepwater prey. Diving is highly regular with most deep foraging dives being followed by an extended period of shallow dives and slow travel and resting near the surface. All foraging dives of both species are considerably ...

Foraging success for pelagic vertebrates may be revealed by horizontal and vertical movement patterns. We show markedly different patterns for leatherback turtles in the North Atlantic versus Eastern Pacific, which feed on gelatinous zooplankton that are only occasionally found in high densities. In the Atlantic, travel speed was characterized by two modes, indicative of high foraging success a...

Emperor penguins (Aptenodytes forsteri) were equipped with a remote underwater video camera, the Crittercam, to evaluate sub-ice foraging behavior while the birds dived from an isolated dive hole. Three birds dived and foraged successfully for 1 h periods after being trained to wear and to dive with a harness for camera attachment. Video and depth profile recordings revealed that emperor pengui...

Foraging animals are influenced by the distribution of food resources and predation risk that both vary in space and time. These constraints likely shape trade-offs involving time, energy, nutrition, and predator avoidance leading to a sequence of locations visited by individuals. According to the marginal-value theorem (MVT), a central-place forager must either increase load size or energy con...

Captive wapiti hinds were observed during seven periods between June 1996 and November 1997. We investigated their activity and foraging behaviour on two pastures, heavily and lightly grazed, during four phases of the reproductive cycle (early gestation, late gestation, peak lactation, and late lactation). Within season, differences in forage availability between pastures had little apparent ef...