CUNNINGHAM, Gregory B.; WEIMERSKIRCH, Henri; NEVITT, Gabrielle A.; Univ. of California, Davis; CNRS, France; Univ. of California, Davis: Blue petrel (Halobaena caerulea) fledglings respond differently to a food-related odor and a novel odor in a wind tunnel.
In a first step towards understanding the ontogeny of olfactory foraging behaviors in Antarctic procellariiform seabirds, we showed that Blue petrel (Halobaena caerulea) chicks are sensitive to both food-related and novel odors. Here we show that such odors elicit different behaviors in a wind tunnel. We measured the behavioral responses of 30 Blue petrel fledglings to cod liver oil (CLO) or phenylethyl alcohol (PEA) against a control (distilled water). We examined behaviors associated with olfactory search including turn frequency, step-length (time between turns), and orientation to the odor. We found that behavioral responses were linked to the order of stimulus presentation. In trials where CLO or PEA was presented first, turning rate was similar to controls, and the time between turns was significantly longer. In trials where CLO was presented second, turning rate was significantly greater than controls, but step-length was similar. Here, no significant differences were found between PEA and controls. Our interpretation is that chicks need time to acclimate to the set-up before beginning exploratory behaviors. Exploratory behaviors (i.e. increased turning behavior) observed were consistent with at-sea observations of adult foraging petrels. In trials where an odor was presented first, birds oriented upwind towards the odor. However, this pattern was maintained during control presentations only for those birds who had been previously exposed to CLO, but not for birds previously exposed to PEA. These data suggest that fledglings respond differently to food-related odors than to novel odors, as CLO modified their behavior in the absence of an odor while PEA did not. These results support the idea that chicks are learning about olfactory cues related to foraging while still in the burrow.
