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I studied predator-prey relationships between goshawk Accipiter gentilis and four species of forest grouse (Tetraonidae) in northern Finland during 1988–1998. The main purpose of my study was to evaluate the impact of goshawk predation and its possible effect on multiannual cycling patterns in grouse numbers. Theoretically specialist predators should tend to cause stable-limit cycles in prey populations if there is a time-lag in the predator's response to prey density and the prey species should be most affected at low densities. Four grouse species, willow grouse Lagopus lagopus, black grouse Tetrao tetrix, capercaillie Tetrao urogallus and hazel grouse Bonasa bonasia, form the main food of the goshawk in boreal forests in northern Finland. Grouse constituted >40% of the goshawk's diet during the breeding season. The impact of predation by breeding goshawks on grouse varied depending on grouse species within 7–32% during the breeding season. Losses were highest for willow grouse and lowest for capercaillie. On average, goshawks took 6% of grouse chicks. On an annual basis breeding goshawks took 2–31% of the August grouse population. The goshawk's share of the total mortality in grouse was also species related. The most reliable estimates were found for black grouse of which 35% were removed and for hazel grouse of which 40% were removed. Goshawks are relatively specialised on forest grouse in northern boreal forests as was demonstrated by a weak functional response of the hawks to changes in grouse density. Breeding goshawks showed no numerical response to changes in grouse density but the production of young tended to lag one year behind black grouse density. The predation rate of goshawks was inversely density dependent on changes in grouse density, which may have had a destabilising effect on the grouse populations. A positive relationship existed between summer predation on willow grouse and changes in the population the previous year.
During October 1998 - May 1999, we studied the distribution of hazel grouse Bonasa bonasia and the structure of their habitats in southern Korea. Hazel grouse were censused from the responses to calls imitated using a Scandinavian metal hunter's whistle in winter and spring along line transects. Hazel grouse were distributed in most of the high mountain forest areas in southern Korea. The frequency of occurrence varied with altitude within the range of 300–1,200 m a.s.l., with the highest density at 600–900 m a.s.l. Altitudinal distribution differed between seasons, however, and hazel grouse were observed at lower altitudes more often in winter than in spring. They occurred in mixed, deciduous and coniferous forest areas, but the use of forest types varied by season. Particularly many individuals were observed in planted Japanese larch Larix leptolepis forests. The coverage and density of understory vegetation was more developed where hazel grouse were observed, but coverage more than 2 m above ground did not seem to be important in explaining hazel grouse presence. The occurrence of hazel grouse was related to the development of understory vegetation more than to forest type. Seasonal use of forest types may have been related to the combined availability of food and cover in understory vegetation.
Managing ungulate populations in a sustainable way requires monitoring plans to provide useful information about population status and trend. Our aim is to evaluate the use of hunters to collect information about the status of caribou Rangifer tarandus groenlandicus in Greenland. Caribou have been harvested under a quota system since 1995 in four regions of west Greenland. In each year, hunters were asked to return information on the sex, approximate age and body condition of animals harvested, and lower jawbones were collected from animals shot in 1995. The harvest is strongly sex-biased (90:10) towards males. Jawbone length did not vary among regions. Age-specific tooth wear was, however, most pronounced in the northern region (Sisimiut-Kangerlussuaq), probably due to the nature of the substrate in the area. The condition of animals, based on a rump-fat index, appears to be good over all west Greenland, with some slight but consistent differences between regions. We conclude that information provided by hunters will be useful in monitoring the caribou populations, but validation of their information is required.
The objective of our study was to examine response distances of Svalbard reindeer Rangifer tarandus platyrhynchus to direct provocation by humans on foot during summer in areas subject to combinations of high or low human activity, and hunting or no hunting. We hypothesised that Svalbard reindeer can become habituated to human activity even when hunted. Reindeer sight, fright, flight and running response distances were measured in response to direct provocation by humans on foot in five areas chosen for their degree of human activity and hunting. No differences in sight distance were found among the five areas. Reindeer in the area with the most human activity in summer and no hunting (Adventdalen) had shorter fright, flight and running distances than reindeer in the area with little human activity and no hunting (Reinsdyrflya). Reindeer response distances in the three areas with hunting and moderate human activity were similar and intermediate to areas with high and low human activity and no hunting There were significant negative correlations between the fright, flight and running distances and the amount of human activity in an area, and with the exception of running distance having a borderline significant value, there were no correlations with intensity of hunting. Our findings suggest that Svalbard reindeer become habituated to human activity and that hunting probably has only a weak or even no influence on it. Furthermore, these findings do not lend support to the hypothesis that reindeer that are hunted by humans are less likely to habituate to human activity than those that are not hunted.
We studied the influence of paragliding flying activity on female chamois Rupicapra r. rupicapra behaviour and distribution in four areas in the Swiss Alps. We observed chamois as they were overflown by co-operative pilots on controlled routes. Female chamois fled at great distances (up to a maximum of 900 m) in all areas and sought refuge within forest cover after paragliders appeared. Escape distances were larger when paragliders appeared over the animals than when they appeared at about the same heights, and were shorter when chamois were closer to forest cover than when they were in open alpine meadows above the timberline. Colour of the paragliders, distance to rocks, and group size did not affect the reactions of the chamois. In areas with regular paragliding, chamois moved away from the air traffic and eventually disappeared into the forest, and did so earlier with increasing flying activity. The chamois stayed within forest cover longer with increased duration of paragliding off the normal flight path. In an area with only sporadic paragliding, chamois sought refuge within the forest for up to four hours after single paraglider fly-overs. In an area with no paragliding, chamois stayed in the pastures and rocks above the treeline all day. This study provides a basis for the development of control measures for paragliding in certain areas.
Different age determination methods were compared to find a practical method for distinguishing between young and adult mountain hares Lepus timidus. The age of the hares was determined using: 1) the ossification stage of the radius and ulna, and 2) the dry weight of the eye lens. The ossification stage of the bones was examined with the unaided eye and palpation, and by using radiography. The proportion of young was higher when the bones were examined using radiography rather than the unaided eye, except in early autumn when the two methods led to the same results. Age determination based on bone examination using the unaided eye gave more reliable results than age determination based on radiography; this became evident when the results were compared with the reproductive status of females or with the dry weight of the eye lens. Using an eye lens weight of 0.25 g as a discriminating value between young and adult hares, gave an age determination similar to that derived from bone examinations using the unaided eye in 90% of the cases. Age determination based on examination of the radius and ulna using the unaided eye and palpation, together with the eye lens weight thus forms a reliable and practical method for distinguishing between young and adult mountain hares, and radiography is only necessary when examining live animals.