Validation and welfare assessment of flipper-mounted time-depth recorders for monitoring penguins in zoos and aquariums

Abstract
The time that penguins devote to aquatic behaviors likely has important implications for their welfare in zoos and aquariums. For decades, field researchers have used time-depth recorders (TDRs) to understand the behavior of penguins at sea. However, zoos and aquariums have rarely used these tools, and wearing devices can potentially affect animals negatively by causing discomfort or imposing energetic costs. We evaluated the longterm behavioral responses of 27 penguins (n=8 king penguins, Aptenodytes patagonicus; n=3 gentoo penguins, Pygoscelis papua ellsworthi; n=8 macaroni penguins, Eudyptes chrysolophus; and n=8 southern rockhopper penguins, Eudyptes chrysocome) before, during, and after wearing TDRs in an ABA study design. Our novel method involved affixing the TDRs to a custom-designed cradle and securing them on the penguins using flipper bands, which the penguins were accustomed to wearing for identification. The experiment was repeated four times, and we used a total of 399.5 h of behavioral observations to evaluate the effects of the TDRs on locomotor, comfort, and social behaviors. We also conducted observations with a second set of penguins (two of each species) naïve to wearing TDRs to evaluate their acute responses following application of the devices. Finally, we conducted validation tests to assess the accuracy of TDRs in a freshwater pool. Penguins observed immediately after the devices were applied to their flipper bands for the first time showed little device-directed behavior. However, there were some individual differences, suggesting that zoos and aquariums should carefully monitor initial behavioral responses to TDRs. In the long term, wearing TDRs had few effects on the behavior of the penguins. The penguins displayed almost no device-directed behavior, and there were few statistically significant differences in their behavior across the three study conditions. Seasonal changes and penguin weight likely explained the increase in movement king penguins demonstrated after wearing TDRs (F2,58=4.34, p=0.02). King penguins also showed a small increase in agonistic behavior while wearing TDRs (F2,73 = 3.81, p=0.03), a difference that may have been related to mating competition during the breeding season. Our results indicate that these flipper-mounted TDRs had few effects on the penguins, while providing valuable information about 24-hour use of aquatic resources in their freshwater habitats.

PUBLICATION AVAILABLE AT: https://www.lotek.com/wp-content/uploads/2019/10/Fuller-Heintz-Allard-2019-penguin-TDR-welfar.pdf