MOVEMENTS AND HABITAT USE BY COMMON RAVENS FROM ROOST SITES IN SOUTHWESTERN IDAHO

Rising conflicts between common ravens (Corvus corax) and humans necessitate a better understanding of the basic ecology of ravens and their interactions with human-altered landscapes. We observed daily movements and habitat use of 31 radio-marked common ravens from 4 communal roosts in southwestern Idaho from April 1985 through February 1987, and recorded their activities relative to various human land alterations (e.g., croplands, cattle feedlots, and refuse landfills). Daily maximum distances traveled from roost sites were similar (P = 0.63) among seasons, but not (P < 0.01) among roosts. Ravens from roosts located within 1 km of a concentrated human-related food source traveled shorter (all P < 0.03) distances from roosts than ravens that were not. Ravens spent an average of 54% of the day in agricultural land, followed by shrub (23%), grass (13%), and riparian habitats (6%). Raven use of various habitats was similar (all P > 0.27) among seasons. Likewise, raven use of agricultural, riparian, and shrub habitats was similar (P > 0.06) among roosts, although use of grass habitats was lower (P < 0.01) at 1 roost. Raven roost locations, daily movements, and habitat use were associated with human-related food sources. Raven populations may be managed through manipulation of raven food supplies, particularly those related to human activities.