Winter Use of Senescent Herbaceous Plants by White-Tailed Deer in Minnesota (Notes and Discussion) (Report‪)‬

INTRODUCTION The winter diet of white-tailed deer in the northern part of its range in North America consists primarily of current-annual-growth of woody twigs, with the remainder composed of green herbaceous plants and ferns and occasionally dried leaves and lichens (Dahlberg and Guettinger, 1956; Snider and Asplund, 1974; Pierce, 1975; Mautz et al., 1976; Mooty, 1976; Crawford, 1982; Verme and Ulrey, 1984; Hodgman and Bowyer, 1985; Dusch et al., 1989; Gray and Servello, 1995). However, in areas of moderate to high deer densities, availability of woody current-annual-growth and other nutritious forages (e.g., evergreen plants and lichens) decreases as winter progresses such that they are often of limited supply by the end of winter. Consequently, to meet minimum daily nutrient requirements, deer must choose between other low quality torage items such as: 1) less preferred woody browse, e.g., alder (Alnus spp.), spruce (Picea spp.) or raspberry (Rubus sp.); 2) older tissues on palatable woody stems that are high in fiber and low in digestible protein (Palo et al., 1992); or 3) plants or plant parts that are readily available but often lower in gross energy and digestibility, e.g., bark, leaf litter, etc. (Amman et al., 1973; Gray and Servello, 1995). Several species of herbaceous perennials present in this region, such as Solidago spp. and Desmodium spp., have relatively tall, rigid sterns that can persist after senescence and extend above the snow pack, thus presenting deer with an alternative forage. During years of high deer densities, winter use of senescent forbs, apparently during the period between snow-melt and spring green-up, has been observed several times in the 1990s in south-central Minnesota, including at Cedar Creek Natural History Area and the Twin Cities Army Ammunition Plant (TCAAP; P.A. Jordan, pers. obs.). Significant winter use of senescent herbaceous plants, however, has never been adequately documented. Our objective was to describe the winter use of senescent forbs by white-tailed deer at TCAAP.