bear update 317 

Cutline: Michael Allen photo THREE’S COMPANY: A sub-adult female black bear and three coastal black-tail deer graze the new grasses and clover on Blackcomb’s Lower Cruiser ski run in early spring. By Michael Allen Black Bear Researcher Welcome to the Whistler Ecosystem Black Bear Project’s third Bear Update column. Black bears leave their dens between early March and late April and for two-three weeks spend more time resting and regaining energy than searching for food. From early April to late April a transition period exists when bears begin to increase their daily food-seeking activity. The black bear is an omnivore (eats vegetation and meat) and not an efficient predator. Insects (ants, bees, wasps, moths), small rodents and carrion (dead animals such as road-kill or winter-kill deer) make up the bulk of the bear’s early spring animal diet. In early spring bears are restricted to feeding on green vegetation in early sprouting and early flowering stages, when cellulose is low. Cellulose is the major ingredient of the cell wall in plants. Bears cannot digest this cellulose completely because they lack the complex stomachs found in deer and cows. When new willow and alder catkins (pussy willows), skunk cabbage flowers, horsetails, grasses, sedges, clovers and leaves from shrubs emerge in April cellulose is low, protein is high and easily digested nutrients are available in the fluids of these plants. As these plants develop and mature with leaves and flowers the cellulose increases, making it difficult for bears to digest them. Annual changes in plant growth are affected primarily by climate. These seasonal changes are referred to as "plant phenology" and direct when and where a bear can feed on plants. For example, huckleberries are the primary food consumed by bears in the Whistler area from July through October. However, huckleberry shrubs are useful to bears before the shrubs are ripe with berries. From late March to mid-April bears forage on the new buds and any berries that have remained on the shrub from the previous fall. From late April, when the first flowers appear on the huckleberry shrub, until the first berries ripen in mid-June bears will forage on the honey-sweetened flowers. Elevation affects the distribution and severity of climate on a community of plants and controls the timing in which plants can be fed or grazed on by bears. Bears usually follow changes in vegetation from the valley, where it emerges or "greens up" first, to the upper slopes of the mountains, where weather delays the timing of green up. For instance, when you ride the ski lifts or gondolas on Blackcomb and Whistler Mountains you can see bears from late April to July grazing at snow-free areas of the ski runs. Bears traditionally follow the green up of ski runs and lift right-of-ways by following the mountains’ snow melt from the base to the top. An advantage to this elevational green up is that new green plants with low cellulose are available to bears from early spring through summer at different times. When grasses develop into mature stems and flowers and the cellulose content becomes too much for bears to digest, bears move to a higher elevational green up site. New, easily digested shoots of green vegetation are now emerging because of recent snow melt. Despite the lush and diverse bear food plants available in the valley, bears continue to feed on garbage if it’s made available. Currently, black bear activity in the valley’s residential communities is low, with an expected increase in May. Proper garbage storage and disposal are the solutions to avoiding the destruction and relocation of bears. Remember to dispose of your garbage at the Nesters or Function Junction compactors and close the doors on the compactors. Bears can be seriously injured when they climb into the compactor and someone closes the door. Avoid leaving garbage at the compactor site when the compactor has been temporarily removed for dumping at the landfill. This just reinforces bears’ desire to look for food at compactor sites, because you are rewarding them with easily available garbage. The fourth Bear Update column will describe the social breakdown of a bear population and the roles of bears during the mating season in late May. If you have any comments about the Bear Update columns, or questions regarding black bears, write to us, care of Pique Newsmagazine.

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