The mesopelagic zone of the northeast Pacific Ocean is an important foraging habitat for many predators, yet few studies have addressed the factors driving basin-scale predator distributions or inter-annual variability in foraging and breeding success. Understanding these processes is critical to reveal how conditions at sea cascade to population-level effects. To begin addressing these challenging questions, we collected diving, tracking, foraging success, and natality data for 297 adult female northern elephant seal migrations from 2004 to 2010. During the longer post-molting migration, individual energy gain rates were significant predictors of pregnancy. At sea, seals focused their foraging effort along a narrow band corresponding to the boundary between the sub-arctic and sub-tropical gyres. In contrast to shallow-diving predators, elephant seals target the gyre-gyre boundary throughout the year rather than follow the southward winter migration of surface features, such as the Transition Zone Chlorophyll Front. We also assessed the impact of added transit costs by studying seals at a colony near the southern extent of the species’ range, 1,150 km to the south. A much larger proportion of seals foraged locally, implying plasticity in foraging strategies and possibly prey type. While these findings are derived from a single species, the results may provide insight to the foraging patterns of many other meso-pelagic predators in the northeast Pacific Ocean.

Stable isotopic analyses of carbon, nitrogen, and sulfur were performed on teeth of different ages and sexes of the longbeaked common dolphin, Delphinus capensis, from the Gulf of California. Similarities in diet are suggested between the sexes, with no significant differences in isotopic compositions being observed. Differences in the ␦ 13 C, ␦ 15 N, and ␦ 34 S signatures were found among the age groups (nursing calf, juvenile, subadult, and adult). These data suggest that this species is generally a coastal feeder, and that it changes its feeding habits with increasing age, drawing more nutrition from higher trophic level organisms later in life.

From July 1998 to July 2000 we collected individuals. Three models of ocelot distribution in Sonora, based on vegetation types, the GARP modelling system locality information and habitat associations for 36 records of the Endangered ocelot Leopardus pardalis in and the Adaptive Kernel home range estimator, all produced similar results, with the ocelot mostly associated the Mexican State of Sonora. Twenty-seven (75%) of the records for which we could determine the biotic with the mountainous Sierra region of eastern Sonora. Large tracts of land with a low human population community association were associated with tropical and subtropical habitats, namely subtropical thornscrub, density make Sonora a stronghold for the northernmost distribution of ocelots. tropical deciduous forest or tropical thornscrub. Only males (11.1% of the total records) have been recorded in temperate oak and pine-oak woodland, and we con-

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