Navigation in Procellariiform seabirds

Thesis

Much of what is known about avian navigation results from half a century of displacement experiments with the homing pigeon, the main model in avian navigation. Whether the same processes underpinning navigation in the homing pigeon are also integral to navigation in other species remains an open question. In particular, how Procellariiform seabirds, which routinely travel huge distances over open ocean, might navigate is of interest because of the contrast in sensory environment compared to terrestrial species. In this thesis, I have three aims. First, to investigate whether the mechanisms involved in homing pigeon navigation might also guide Procellariiform seabirds over the ocean. Second, to establish whether GPS-tracked, free-ranging Procellariiform seabirds might be able to offer insights into avian navigational mechanisms. Third, to investigate some of the ecological drivers of long-distance movement facilitated by these navigational mechanisms in Procellariiform seabirds. By combining novel experimental and analytical approaches, I attempt to answer some of these questions. I find that many of the mechanisms though to guide homing pigeons also appear to underpin Procellariiform navigation. In particular, the involvement of information from the time-compensated sun-compass, central to structuring spatial representation in terrestrial species, seems to be very similar to that observed in pigeons. Furthermore, like pigeons, olfaction seems to play a specific role in Procellariiform seabirds’ map sense. However, there are differences too. I make the tentative discovery that, perhaps unlike pigeons, shearwaters might be able to derive information exocentrically about their location at sea in the form of a vector of direction and distance from the home colony, implying a geometric cognitive representation of large-scale environmental gradients. Finally, in terms of ecological drivers of long-distance movement, I find that Manx shearwaters’ migratory phenology is probably constrained by their environment and not by their condition, in-keeping with the idea that long-distance movement comes at a low cost for Procellariiform seabirds.

Authors: Padget, O

• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: Scopoli's shearwater; Sun compass; Cognitive Map; Navigation; Olfactory navigation; Procellariiform seabirds; Manx shearwater
• Subjects: Ornithology; Evolution; Animal behaviour; Ecology; Behavioural Ecology