Seabird sensory ecology and conservation

Abstract

Seabirds live in extreme environments. After fledging, they spend the majority of their lives foraging on the vast ocean landscape, coming to shore only to breed. Most seabirds also exhibit strong pairbonding, monogamy, and philopatry. These behavioural and ecological traits make them fascinating subjects for sensory ecology research. Sensory perception is integral in all aspects of seabird biology, including sexual selection, evolution, and ecology. Seabirds are also one of the most at-risk groups of birds in the world due to threats faced both at sea and on sensitive breeding colonies, and sensory-based management efforts offer a powerful new approach for conservation. Firstly, this thesis examines the use of seabird sensory ecology from an applied conservation perspective. A comprehensive review of the uses of sensory –based techniques highlights the importance of this field for the conservation of seabirds indicates how these methods could be applied to other taxa with similar life histories and behaviours (Chapter 1 in press, Biological Reviews). Experiments testing the use of sensory stimuli for the attraction of grey-faced petrels (Pterodroma gouldi) to restored habitat (Chapter 2) indicate that not all sensory modes, or acoustic stimuli, are equally effective. Playback of attractive calls and supernormal acoustic signals were more effectiv than aggressive calls. Naturally scented nest material neither attracted nor deterred birds from nest boxes. Secondly, I examine the sensory ecology of seabirds from a theoretical perspective. Procellariiform seabirds such as petrels, shearwaters, storm petrels and albatross, are a more basal avian lineage and have some sensory traits that reflect their phylogeny (e.g. large olfactory bulb ratios), and have been thought to lack the ability to learn complex communication that is exhibited in songbirds (Oscines). Investigations into grey-faced petrel vocalizations revealed previously unknown complexities of their call repertoires (Chapter 3) and experimental manipulations indicate the first ever evidence of vocal matching in a seabird species (Chapter 4). Finally, this thesis examines olfactory communication and offers the first demonstration of a phylogenetic basis of odour in birds. Odour composition was linked to species and phylogenetic relatedness, for six species of seabirds from two orders (five Procellariiformes and one Sphenisciformes- penguins). By using a holistic approach, this thesis shows the centrality of sensory ecology in seabird biology, the complexity of seabird sensory adaptations, and how these can be harnessed in conservation.