Bear response to supplemental feed offered to reduce tree peeling

Abstract

Black bears (Ursus americanus) strip bark from coniferous trees to feed on newly forming vascular tissue during spring. Damage inflicted through this behavior can be extremely detrimental to the health and economic value of timber stands. A supplemental feeding program to provide bears an alternative food source during spring is practiced by some resource managers. We evaluated the efficacy of the program and conducted concurrent studies to assess select behavioral characteristics of feeding bears and impacts of providing supplemental feed on nutritional status of bears. The efficacy study revealed the percentage of damaged trees in stands with foraging bears varied from 2% to 52%. When supplemental feeding was introduced on these stands, damage was reduced to approximately 10% of that sustained on untreated stands. Concurrent experiments provided insightful data on bear use of feeding stations. Numerous bears fed at the stations, including females with and without cubs, yearlings, and boars. Bear feeding bouts at the stations were generally short, less than 30 minutes. Bears generally fed alone, although 2 to 3 adult bears were observed at a feeder simultaneously and the feeding partners were not consistent. There was little antagonistic behavior observed around the feeders, and no evidence that this behavior inhibited foraging opportunities for long. On the rare occasion a bear was driven from a feeder it returned later that same day to feed, generally within an hour. Supplemental feeding also did not affect the home range sizes of bears in feeding areas, but it may serve to concentrate bears in a particular location. Bears consuming supplemental feed did gain a significant nutritional advantage while feeding, but this did not equate to long term increases in age-specific body masses or fat content.