RADIO TRANSMITTERS DO NOT AFFECT NESTLING FEEDING RATES BY FEMALE HOODED WARBLERS

Few studies have examined the effects of radio transmitters on behavio r, particularly of small passerines. Only recently have transmitters b een made small enough for use on birds under 20 g. To determine if rad io transmitters reduce activity levels, female Hooded Warblers (Wilson ia citrina) were fitted with transmitters while they were feeding nest lings. Females with transmitters and harnesses weighing 7-8.5% of body mass did not feed nestlings less frequently than did control females. Males mated to females with transmitters did nor feed nestlings at di fferent rates from males mated to control females. Brooding time and t ime spent perched on the edge of the nest did not differ significantly between tagged and control females. The finding that transmitters did nor affect an energetically demanding activity such as feeding young suggests that other aspects of female behavior also were not adversely affected.