Characteristics of Summer Beds of European Brown Bears in Norway

One hundred and nineteen European brown bear (Ursus arctos arctos) daybeds and their surroundings were studied in Hedmark County, Norway, in 1974 -77. In addition to bed type and size, the following parameters were measured or estimated: slope, aspect, altitude, type and age of vegetation, cover, distance to close objects, and distance from the site to farms and roads. Abiotic exposure avoidance, concealment, defense/safety, and construction behavior are discussed as elements of bed site selection. Bed studies based on field signs met with difficulties such as distinguishing daybeds from dens, and problems of bed classification are discussed. Int. Conf. Bear Res. and Manage. 5:208-222 Terrestrial mammals exhibit 3 major sleeping and resting positions, the curled, the stretched, and the sitting posture. In certain species these basic postures have been greatly modified, and some may rest in both standing and recumbent positions (Hafez 1975). In general, brown bears rest in the loosely curled posture, and the term bed is used here for any spot where an animal curls up on a substrate leaving body prints or other signs identifying the site. Bedding behavior as studied here was based on beds as field signs only, and not by direct observation. Judging from the amount of time spent bedding, this behavior is important for bears during the whole annual cycle, both summer and winter. A radio-marked Alaskan grizzly bear (U. a. horribilis) spent 31% of its time feeding, 10% travelling, and 59% bedding during May-June (S. Linderman, pers. commun.). Although we have no comparable investigation of the closely related European brown bear, numerous beds seen during the Hedmark bear study indicate that bedding is of similar importance in their activity patterns. During winter it is well known that the bears bed down for a prolonged period inside a den (Vroom et al. 1980). While den bedding during winter has been extensively studied, summer bedding has not. Except for the data on daybeds for the grizzly bear in the Yellowstone area, USA, collected by the Interagency Study Team (R.R. Knight et al., unpubl. rep., U.S. Dep. Inter. Natl. Park Serv., 1978), summer bed characteristics for bears have been little considered. The aim of the present study was 2-fold. It was intended as an investigation of typical summer and autumn daybeds, for the identification of as many behavioral elements associated with bedding as possible, and also for a description of the parameters usable for predicting the potential of varying structural forest stands as bedding locations. Information on bedding preferences in forests treated according to modern silvicultural practices is needed for management. Beds were used for varying periods and purposes, and thus had different characteristics. The other aim of the study was to suggest a general scheme for bed type and to discuss bed classification problems of the whole annual bedding cycle. The author is indebted to Mr. Nils Rotheim, Hedmark Forest Service, for statistical information; Mr. Terje Aven, University of Oslo, for statistical advice; Dr. Nils Christian Stenseth, University of Oslo, for critical reading and commenting upon an earlier draft of the manuscript; and to Mr. Robert Vinter for improving the English. Mr. Kjell Andersen, Mr. Ragnar Odegaard, and Mrs. Erika Leslie have given technical assistance. The Hedmark brown bear research program was supported by grants from the Norwegian Research Council for Science and the Humanities, by Fridtjof Nansen's and affiliated Funds for the advancement of Science and the Humanities, and by the Directorate for Wildlife and Freshwater Fish.