Effects of Backpack Radio-Transmitters on Female Barrow’s Goldeneyes

— We compared time-budgets and return rates of breeding female Barrow’s Goldeneyes ( Bucephala islandica ) fitted, or not, with transmitters attached with backpack harnesses in 2001-2004 in southern Quebec. We compared the mean proportion of time devoted to feeding, locomotion, alert, resting, preening, and maintenance (i.e., resting plus preening) by females observed ≥ 200 min. Females with backpacks (N = 5) spent significantly less time feeding (x ± SE: 25 ± 5% versus 43 ± 3%) and more time in maintenance activities (51 ± 6% versus 31 ± 4%) than females without transmitters (N = 6). Mean time devoted to other behavior did not differ significantly. Upon release, females appeared disturbed with the backpack, actively bathing, preening and/or flapping wings. Of the females with transmitters observed ≥ 200 min, three spent 4%, 8%, and 57% of their preening time at their transmitter, antennae or harness. None of the 16 females harnessed in 2001-2003 were recaptured in nest boxes or seen again on the study area in 2002-2004. For comparison, 66% of adult female Barrow’s Goldeneyes captured in nest boxes and marked with leg bands in 2000-2002 were recaptured or seen again in subsequent years. We do not recommend the use of harnesses on diving ducks and sea ducks as it may affect their behavior and survival, at least for birds wintering in areas where conditions are severe. Received 5 September 2005, accepted 16 December 2005.