. 1992. Prédation of foxes o.ï a hare population in central Poland. Acta theriol. 37: 329 -338.The relationship between foxes Vulpes vulpes (Linnaeus, 1758) and hares Lepus europaeus (Pallas, 1778) was investigated in central Poland. The consumption of hares by foxes was the highest (up to 50% of biomass eaten) during the spring seasons. The negative correlation between small mammal and hare consumption by foxes was recorded throughout the study. Lack of small mammals in spring as well as low temperatures and deep snow cover in winter intensified the fox hunting on hares. The reduction of hares by foxes was about 16% during spring to autumn and 8% in winter. Predators were responsible for 50% of the total mortality of adult hares. By snowtracking of foxes it was established that the mean distance between successful hunts on hares was 263 km of fox trail. Foxes captured on average one hare every 19 days. About 7% hare hunts by foxes were successful.
We describe the results of our research on population dynamics among brown hares reared in enclosures and then released into suitable natural habitat. Radio-tracking was used to follow the fate of 60 released brown hares over a 4-year period, extending between November 2005 and November 2009. The survival rate among these animals after 12 months was estimated to be 37 %, with 22 tagged individuals surviving beyond 1 year post-release. The highest (40 %) level of mortality characterised the first month after release, while a second period of enhanced mortality coincided with the breeding season (altogether accounting for a 20 % mortality rate). There was no significant relationship between body mass and mortality rate in the first month following release. A natural cause of death was predation by mammals, which accounted for some 31 % of all losses. Remaining causes were poaching (13 %), hits by vehicles (7 %) and unidentified causes (9 %). However, in at least 40 % of cases, it was not possible to determine the date when a released animal died, to say nothing of the cause of death.
. 1996. Physical condition of red deer in a high density population. Acta Theriologica 41: 93-105.Physical condition in a living at high density (120 individuals/1000 ha of forest area) red deer Cervus elaphus Linnaeus, 1758 population was studied by determining: dressed body weight, kidney fat index (KFI) and amount of visceral fat in 628 animals. Antler weights were also considered as condition index of stags. The mean body weight of calves of both sexes was identical, ie 38.0 kg, that of hinds fluctuated from 57.8 to 75.1 kg, stags -from 63.2 to 132.4 kg depending upon age. The KFI value for female and male calves, hinds, and stags at various age amounted respectively to: 1.54, 1.36, 1.60-1.76, and 1.17-2.69. Per cent of individuals with great amount of visceral fat amounted: in female calves -to 39.4, in male calves -33.3, in hinds -47.6-66.7, and in stags -20.0-100.0% depending upon age. Maximum weight of antlers was 4.2 kg. Despite high population density animals indicated generally good physical condition. Except that the condition of calves of both sexes has been maintained at a similar level, what evidenced an inferior condition of males during their growth. Males in contrast to females, reveal serious decline of condition following the rut, during autumn and winter. It was related to stag age and most marked in the animals of the oldest age-classes (no less than by 40%). Factors affecting the condition of red deer in their population from the Słowiński National Park were discussed.
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