Exploring the Development of Olfactory Sensitivity in a Procellariiform Seabird

University Of California-Davis, Davis CA

Investigators

Abstract

Procellariiform seabirds (the petrels, albatrosses and shearwaters) make their living foraging over vast expanses of open ocean hunting patchily distributed prey such as fish, squid and krill. The secret to their success is an ability to locate prey by smell. Over the past decade, much headway has been made in understanding olfactory foraging of Antarctic species, both at large (>100s of miles) and small (<10 miles) scales. Augmenting early work by leading scientists, the Principal Investigator's (PI) broadly integrative approach to studying olfactory foraging has expanded the picture of how seabirds "see" the world with their noses. Now many questions arise. For example, how do olfactory foraging behaviors develop in chicks? While other pelagic seabirds spend months teaching offspring how and where to forage, procellariiform chicks fledge and survive the open seas weeks after their parents have dispersed. These birds appear to hatch knowing how and where to forage without aid or instruction from a parent. How is this possible? Drawing from disciplines as diverse as atmospheric chemistry and developmental neurobiology, this proposal explores the hypothesis that, during development, chicks become tuned to odors used in foraging by being exposed to them by their parents. This pre-tuning or "imprinting" provides birds with information about the olfactory landscape they will encounter after fledging, and, specifically, offers them clues about where foraging is likely to be productive. This proposal investigates the development of olfactory sensitivity in the Leach's storm petrel (Oceanodroma leucorhoa). There are two primary objectives. First, chicks' behavioral responses to three prey-related odors (DMS - plankton scent, pyrazine - krill scent, and trimethyl amine - fish scent) and to one control odor (phenyl ethyl alcohol - rose scent) will be characterized. The second objective will determine whether chicks learn odor cues by pre-exposing chicks to a non-prey related odor during the egg stage, and then testing whether this early exposure increases sensitivity to that odor later in life. Results from the proposed research will be among the first to address the development of olfaction in an ecologically important context. In addition to her seabird work, the PI has been a key player in developing new and highly integrative approaches to studying salmon imprinting, so extending these ideas to birds is a logical progression of her work. Overall, the results will greatly extend our knowledge of the sensory biology of these fascinating birds. Such knowledge not only is useful to basic science, but also may help bolster efforts to ensure the conservation of procellariiforms, given the threatened or endangered status of many species. Moreover, by establishing a study site at a University-sponsored field laboratory, student involvement in the work will be much more easily fostered. Relative to the remote sub-Antarctic, where virtually all of the PI's previous work has been conducted, Kent Island (New Brunswick, Canada) is easily and economically accessible. The location also provides access to lab facilities (not typically available on isolated islands where procellariiforms breed) and collaborators from around the world, as well as the ability to mentor graduate and undergraduate students in the field.