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Habitat selection by 58 ring-necked pheasants Phasianus colchicus was studied using radio-telemetry during the breeding season (March-September) in an intensively farmed region of northern Italy, characterised by only 1.7% of woodland (shelter belt plantations), and a high density of pheasants (30.4 individuals/100 ha in the pre-breeding season). Habitat selection was tested using compositional analysis. We also tested for effects of sex and age, differences between seasonal and daily time periods, and nest site selection. Moreover, relationships between habitat and home-range size were examined. The analysis showed the importance of cover provided by the shelter belts, accounting for 24.7% of radio-locations, which strongly influenced both habitat selection and home-range size. Season affected habitat use with both sexes increasing their use of cropland in summer; in late summer cropland not only provides food (both vegetation and arthropods) but also cover. We did not find significant differences between habitats selected for nesting and other habitats used by hens. We found a clear negative correlation between distance from shelter belts and use by pheasants, with only 1% of radio-locations >800 m from shelter belts. Our results suggest that the introduction of arboreal shelter belt plantations in the countryside, set maximum 1,600 m apart, may improve habitat quality for pheasants.
The predation behaviour of six lynx Lynx lynx family groups, i.e. adult females with dependent kittens, was studied using radio-tracking and snow-tracking in the Sarek area of northern Sweden during winter 1995/96 and 1996/97. One hundred and six daily radio-locations were obtained, and 340 km of intervening tracks were followed in the snow. Forty-one scats were collected, and 57 hunting attempts, 37 of which were successful, were recorded. Semi-domestic reindeer Rangifer tarandus contributed over 90% to lynx ingested meat calculated from both scats and kills. Eighty-three percent of hunting attempts on reindeer, and 53% of attempts on small prey species, mainly Lagopus sp. and mountain hares Lepus timidus, were successful. Four incidents of multiple-killing of reindeer were documented. Reindeer were generally in poor body condition, with an average femur marrow fat content of 27%. Lynx spent an average of three nights at each reindeer kill-site. Reindeer were less completely consumed than small prey (61% vs 99%). The amount of meat eaten from a reindeer was proportional to the number of lynx-nights on the kill. An overall kill rate of one reindeer per five days was calculated. We concluded that reindeer are a very important food source for lynx in winter, which potentially could lead to problems in resolving the camivore-livestock conflicts in the region.
We explore some of the consequences of harvest on population growth rate, age and sex structure in a Norwegian population of red deer Cervus elaphus, using age-structured demographic models. Survival rates were estimated from individuals marked and monitored annually during 1977–1995, and information about reproduction patterns were obtained from hunting material in the same region. The population had an actual doubling time of 14 years, corresponding to a multiplication rate of 1.051. Harvesting led to a reduction of about 10% of the potential multiplication rate that equalled 1.166. Including stochasticity had only a small effect on the population multiplication rate. Due to a high hunting pressure, males had less than a 10% chance of reaching 4.5 years of age and the male-biased harvest strongly biased the sex ratio. Assuming that when the number of females per male increases above a given threshold some females would not manage to mate, we investigated at which level male harvesting could be maintained without having demographic consequences on the population growth rate. We concluded that the hunting pressure on males could probably be increased further but indirect consequences of a strongly biased sex ratio (e.g. on population genetic structure) remain to be studied. Variation in the multiplication rate mainly resulted from the variation in winter calf survival. In its present form the harvesting regime reduces the growth rate and biases the sex and age structure, but does not seem to threaten the population's viability and productivity.
Bed-site selection by 19 radio-collared roe deer Capreolus capreolus fawns from seven family groups was studied during June-July 1998 in southeastern Norway. The habitat consisted of small agricultural fields surrounded by industrially exploited boreal forest. Within the forest, fawns selected bed-sites that offered greater concealment, higher vegetation and more canopy cover than random sites. No such selection was evident within the homogenous pasture on the fields. Bed-sites in fields offered greater concealment than those in the forest, where there were no detectable differences between stand age classes. Compositional analysis revealed a significant preference for bed-sites to be located in forest, although fields and bogs were often used. Within the forest, stands of all age classes were used. The broad use of habitats may either reflect that habitats were equally good, or it may be a strategy to increase the area a predator has to search in order to find a fawn.
In Finland, monitoring of the moose Alces alces population has been based on moose sighting cards and on aerial or ground censuses. However, considerable criticism has been levelled at these techniques, and there is an increasing need for alternative census methods in monitoring and managing moose populations. In this study, pellet group counts were carried out to determine the density and habitat use of moose in a wintering area in central Finland. Pellet group counts were made using both strip and plot sampling procedures. Estimates of moose density depended significantly on the sampling procedures and on the parameters used. Moose density estimates based on plots were twice those based on strips. Different plot intervals in plot sampling gave similar results. Both sampling procedures gave similar results concerning the habitat use of moose. The highest pellet group densities were observed in young Scots pine Pinus sylvestris dominated thinning stands where winter food availability is considerably high. Because food is a limiting factor in winter, pellet group numbers should obviously well reflect moose habitat affinity, which can be classified in terms of forest stand characteristics. Pellet group counts could possibly be used to estimate population densities for moose management. However, it would appear that the plot method, which up to now is the widely used method, overestimates moose densities. Because of the great variation in the results, other possible sources of error in the parameters used should also be taken into account in order to improve the accuracy of the method to be applied.
The influence of water vole Arvicola terrestris scherman fluctuations on red fox Vulpes vulpes reproduction was investigated in a central European mountainous habitat. We also examined the relationship between annual variations in the mean body weight of the cubs and trophic changes. Water vole abundance was estimated by seasonal trappings, and fox families and cubs were counted every spring. The number of fox families differed little between years, and the differences were not related to water vole abundance. Mean litter size also varied from year to year, but independently of water vole densities. No relation was found between the weight of the cubs and water vole supply. The lack of any significant annual variations in fox breeding success means that despite the low availability of wild alternative prey, foxes found suitable trophic conditions in the absence of water voles. Moreover, as suggested by the increase in the consumption of food scraps by foxes during vole lows, man has certainly been instrumental in preventing a decrease in fox breeding success at the low stage of the water vole cycle.
The suitability of intraperitoneally implanted radio-transmitters as a method for studying young lynx Lynx lynx kittens was tested under field conditions. Radio-marked adult females were followed to the lair where they kept their kittens. In 1997 and 1998, nine kittens (4–5 weeks old) were located. One of two implant models (7 g and 20 g) were implanted using surgical procedures and a combination of medetomidine (0.08 mg/kg) and ketamine (5 mg/kg) for anaesthesia. No complications occurred during the operations. All kittens were accepted again by their mother and were moved to a new lair within 1 km. All survived at least three months after the operation. Six of the kittens were re-examined 4–5 months after the operation. In all of these cases the implants were floating freely in the peritoneal cavity. Based on these results it appears that intraperitoneal implanting of radio-transmitters is a very useful method for studying very young lynx kittens, and could be used for most felids of a similar, or larger, size.
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