Les hommes ont oublié cette vérité. Mais tu ne dois pas l'oublier, dit le renard. Tu deviens responsable pour toujours de ce que tu as apprivoisé.
Le Petit Prince, chap. 21

Thursday 15 August 2013

Diet and home range of feral cats in Galápagos

Konecny, M. J. (1987). Home range and activity patterns of feral house cats in the Galapagos Islands. Oikos50: 17-23.

The spatial organization of two populations of feral house cats Felis catus, was examined in the Galápagos Islands using mark-recapture and radio telemetry. Both populations were located in the same habitat vegetation type and had approximately equal densities of cats. Two sites differing in resource density and habitat heterogeneity also differed significantly in home range size and amount of overlap. Male home ranges averaged 3.04 kmwhile those of females averaged 0.82 km2. Monthly home ranges did not vary significantly. Activity patterns were roughly bimodal with peaks near dawn and dusk and lows near midday. Daily movement paths differed between sites. Resource levels and home range patterns suggest a resource threshold territoriality based on resource depression at the poorer site while no territoriality was found at the richer site demonstrating the adaptability and ecological flexibility of feral cats.

Konecny, M. J. (1987). Food habits and energetics of feral house cats in the Galápagos Islands. Oikos, 50: 24-32.

The food habits of feral cats (Felis catus) were assessed by visual observations and scats collected in two seasons and at two sites in the Galápagos Islands. Cats were seen to both scavenge and attack live prey with a capture efficiency of 32%. In seasonal comparisons significantly more food items were included in the dry season (7.4) than the wet (5.7). Significantly more items were included in the diet at Tagus Cove (7.8) which was less productive than Cerro Colorado (6.7). The diet included both vertebrate and invertebrate prey but vertebrates constituted 71.9% of each scat by weight and 93.4% of the energy. The estimated daily intake of energy was 170 kcal which is at the caloric break even point for non-pregnant females, slightly below that for adult males and pregnant females and well below that for lactating females. The food habit and energetic data were combined to make some predictions about food preferences, foraging decisions and the role of available water on feral cats.

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