EFFECTS OF WINTER SUPPLEMENTAL FEEDING ON BROWSE CONSUMPTION BY WHITE-TAILED DEER

Supplemental feeding of wintering white-tailed deer (Odocoileus virgin ianus) has increased in recent years, yet little data address its impl ications. During January-March 1993 and 1994, consumption of supplemen tal feed, provided ad libitum, was monitored daily at 2 recently estab lished supplemental feeding (RSF) sites in northcentral Minnesota. We also monitored browse availability and use monthly at the 2 RSF sites and at 2 control (no supplemental feeding) sites by a sequential clipp ing method. Cumulative feed consumption and deer-visits were consisten t between sites within years, but not between years; greater feed cons umption and deer-visits occurred during the more severe Winter 1994. B rowse pressure differed (P < 0.0001) by month during Winter 1993, and by month, twig density (sparse, moderate, dense), and site during 1994 . A site x distance interaction (P < 0.0001) in 1993 was not significa nt in 1994 when browse pressure was higher. During 1994, mean browse p ressure at control and RSF sites was different (P < 0.0001). A key fin ding in our study was that supplemental feeding effects differed annua lly. Furthermore, in both years, browse pressure means of both RSF sit es differed, in the same manner, from mean browse pressure at the 2 co ntrol sites. The observed consistency of response among replicates, wi thin treatments and years, suggests that supplemental feeding effects may apply generally to other local deer populations.