In the past few years there has been much theoretical work on optimal foraging behaviour in animals. It relates to the assumption that animals tend to optimize their feeding activities. Reviews appear in Schoener (1971), MacArthur (1972), Emlen (1973) and Pianka (1974). Interest has been paid particularly to optimal choice of diet for predators with a choice among different prey types (Charnov ...

Previous studies of desert tortoise foraging ecology in the western Mojave Desert suggest that these animals are selective herbivores, which alter their diet according to the temporal availability of preferred food plants. These studies, however, did not estimate availability of potential food plants by taking into account the spatial and temporal variability in ephemeral plant abundance that o...

Spatial distributions of 22 mature large-framed Beefmaster × Simford (BS) cross cows and 16 mature small-framed Baladi (BA) cows were determined. Cows were allocated to the same paddock of a Mediterranean pasture and monitored during 6 consecutive seasons: spring (April 2006), summer (June 2006), autumn (September 2006), winter (February 2007), early spring (March 2007), and summer (June 2007)....

Foraging niche specialization is thought to occur when different members of speciose communities divide resources in either time or space. Here we compared habitat preferences the congeneric Grey Petrel Procellaria cinerea and White‐chinned aequinoctialis , tracked same calendar year using GPS loggers from Gough Island Bird (South Georgia), respectively. We identified periods active foraging de...

Many pinnipeds frequently rest on land or ice, but some species remain in open waters for weeks or months, raising the question of how they rest. A unique type of dive, called drift dives, has been reported for several pinnipeds with suggested functions of rest, food processing and predator avoidance. Prolonged surfacing periods have also been observed in captive seals and are thought to aid fo...

The time budgets, behavior rhythms, foraging habitats and food preferences of oriental white stork Ciconia boyciana were studied from December 2013 to March 2014 with instantaneous scan sampling and focus animal sampling methods at Poyang Lake, Jiangxi province, China. The results showed that the main behavior of oriental white stork were resting (40.07±3.21%) and foraging (35.44±2.42%), follow...

Animals can maximize fitness by optimizing energy acquisition through the selection of favorable foraging habitats, but trade-offs exist between time spent in preferred feeding habitats, energetic costs of travel, and reproductive constraints. For pelagic seabirds, geographic distribution of suitable breeding islands can restrict access to marine prey resources and influence foraging strategies...

Unlike terrestrial birds, many species of seabirds forage far from their breeding sites. Alternating nest attendance by the two parents allows for long distance foraging trips during lengthy incubation periods. Even so, limited food availability or poor weather can sometimes delay birds in their return to the nest. Thus, egg temperatures may drop to ambient levels for periods of a day or more (...

in the deregulated power systems, transmission congestion is one of the significant and main problems of the electrical networks which can cause incremental cost in the energy. this problem has resulted to new challenging issues in different parts of power systems which there was not in the traditional systems or at least had very little importance. transmission congestion happens when the maxi...