Aquatic feeding by moose: seasonal variation in relation to plant chemical composition and use of mineral licks

Abstract

Activity of moose (Alces alces) was studied at aquatic feeding areas and at natural, sodium-rich licks during four periods covering late May to early September. Aquatic feeding increased from period 1 (late May and early June) to period 2 (late June and early July) and had declined by late July. Major activity at mineral licks occurred earlier in the season than aquatic feeding, especially for males. Chemical composition of aquatic plants showed no seasonal changes corresponding to the peak of aquatic feeding in period 2, although the sodium content of some species declined in period 3. We suggest that moose in the study area are attracted to sodium sources from late May to mid-July, that aquatic feeding replaces use of licks in June as the most sodium-rich aquatic plants become abundant, and that both activities decrease in midsummer because of declining attraction to sodium.