As obligate scavengers, vultures and condors exhibit specialised traits that allow them to move across large spatial scales to locate and consume carrion before it becomes inedible or is consumed by other scavengers (Janzen Reference Janzen1977, Shivik Reference Shivik2006). Reference DeVault, Rhodes and Shivik2003, Wilson and Wolkovich Reference Wilson and Wolkovich2011 but see Moreno-Opo and Margalida Reference Moreno-Opo and Margalida2013). Indeed, only a subset of the world’s vultures and condors can be classified as true obligate scavengers (Ruxton and Houston Reference Ruxton and Houston2004) although carrion is used by a wide range of animals with carnivorous diets (DeVault et al. Obligate scavengers feed exclusively on carrion, a foraging strategy that is rare among terrestrial vertebrates. Our study provides an important foundation for understanding the movement ecology of the California Condor and it highlights the importance of seasonal variation in space use for effective conservation planning for this critically endangered species.Ĭarrion is common in all ecosystems, occurring as a resource that is patchily distributed over large spatial scales and highly ephemeral in its availability as a food resource (Janzen Reference Janzen1977, Houston Reference Houston1985). Individuals from each of three release sites differed significantly in the size of their monthly home ranges, and no differences in monthly home range size were detected between condors reared under captive conditions relative to those reared in the wild. Monthly home ranges of adults were significantly larger than those of immatures, but males and females used monthly home ranges of similar size throughout the year and breeding adults did not differ from non-breeding adults in their average monthly home range size. We found that monthly home range size varied across the annual cycle, with the largest monthly home ranges observed during late summer and early fall (July–October), a pattern that may be linked to seasonal changes in thermals that facilitate movement. We assessed whether individual-level characteristics (age, sex and breeding status) and factors related to endangered species recovery program efforts (rearing method, release site) were linked to variation in monthly home range size. In this study, we used high-resolution GPS location data to quantify monthly home range size of the critically endangered California Condor Gymnogyps californianus throughout the annual cycle in California. Condors and vultures comprise the only group of terrestrial vertebrates in the world that are obligate scavengers, and these species move widely to locate ephemeral, unpredictable, and patchily-distributed food resources.
0 Comments
Leave a Reply. |