MEPS 333:281-289 (2007)  -  doi:10.3354/meps333281

ABSTRACT: Externally-attached transmission and logging devices have greatly helped elucidate the biology of free-living animals over the last 50 yr. However, such devices may hinder animals so that the behaviour monitored is not representative of unequipped conspecifics. We suggest that if animals are equipped with devices of varying size, the change in recorded parameters with size can be used to extrapolate to the condition in unencumbered animals. Use of this approach with Adélie penguins Pygoscelis adeliae showed that unequipped birds are predicted to range farther, swim faster, dive deeper and be more efficient underwater than equipped birds. The derived data not only set baseline information for the species concerned but also allow us to put the deleterious effects of the devices into perspective.

KEY WORDS: Data-logger impact · Bio-logging · Spheniscids · Adélie penguins · Pygoscelis adeliae · Swim speed · Diving performance · Foraging