SEASONAL USE OF SALT BLOCKS BY MOUNTAIN HARES IN SWEDEN

Salt blocks placed afield by Swedish hunters for wild ungulates also a re used by mountain hares (Lepus timidus). However, little is known ab out the seasonal patterns of salt use by hares, a fundamental consider ation regarding the potential benefit of this mineral appetite. Thus, we monitored the use of salt-block (NaCl) stations by mountain hares a t the Grimso Wildlife Research Station, Riddarhyttan, Sweden from Apri l 1988 to June 1989. Use of the stations peaked between April and July , declined to a low in january, and then rose again to the April-July peak. We suggest that this use reflects an appetite for sodium (Na) th at may result from the ingestion of plant secondary compounds, a seaso nal excess of dietary potassium, and/or the nutrient demands of growth and reproduction. We also suggest that wildlife managers might benefi t by learning why mountain hares have increased Na appetites at certai n times of the year.