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Habitat related differences in age structure and reproductive parameters of red foxes

100%

Gortazar C., Ferreras P., Villafuerte R., Martin M., Blanco J. C.

Acta Theriologica

2003

tom 48

nr 1

We studied the age-structure and the reproductive parameters in two samples of red foxesVulpes vulpes (Linnaeus, 1758) from two contiguous areas in the Ebro valley (NE Spain) differing in the level of deliberate culling and in the habitat quality. Percent of juvenile foxes in the semiarid steppe (under higher persecution) was lower (53%) than in the irrigated highly productive “vegas” (67%). Conversely, foxes in the “vegas” (more favourable habitat) had a larger litter size (3.9 ± 0.23 cubs per female) and a higher amount of barren vixens (19.3%) than in the steppe (3.3 ± 0.12 cubs per female, and 1.7% of barren vixens). In this study, migration due to juvenile dispersal does not hide the effects of the habitat on fox population dynamics, despite the proximity between both areas. The results are discussed in relation to previous studies on red fox population dynamics.

Evidence of non-hibernation in Cantabrian brown bears

86%

Nores C., Ballesteros F., Blanco J. C., Garcia-Serrano A., Herrero J., Palomero G.

Acta Theriologica

2010

tom 55

nr 3

203-209

Evidence of non-hibernation in brown bears Ursus arctos Linnaeus, 1758 on the Iberian Peninsula has existed since the Middle Ages. We systematically monitored brown bears in the Cantabrian Mountains (Northern Spain) by recording tracks and sightings from 1998 to 2007 to document hibernation behaviour. Our results indicate that females with yearlings and solitary yearlings were more active in winter than bears over two years old. Intensive snow tracking and direct observations of five family groups indicated that they travelled, fed and defecated in winter, which are activities not compatible with the physiological state of hibernation. Also, based on tracking data, the maximum period between two consecutive locations of active family groups in winter was less than that needed by bears to emerge from a state of hibernation (6 days). We conclude that the family groups which we monitored in winter did not hibernate.

Ograniczanie wyników

2 Acta Theriologica

2 Blanco J. C.

1 Ballesteros F.

1 Ferreras P.

1 Garcia-Serrano A.

1 Gortazar C.

1 Herrero J.

1 Martin M.

1 Nores C.

1 Palomero G.

1 Villafuerte R.

1 2010

1 2003

Wyniki wyszukiwania

Habitat related differences in age structure and reproductive parameters of red foxes

Evidence of non-hibernation in Cantabrian brown bears