Olfactory foraging in Antarctic seabirds:a species-specific attraction to krill odors

Abstract

Antarctic procellariiform seabirds are known for their well-developed sense of smell, yet few behavioral experiments have addressed how these birds use olfactory cues to forage at sea. I describe results from controlled, shipboard experiments performed in Antarctic waters near Elephant Island. Birds were presented with plain or krill-scented (Euphausia superba) vegetable oil slicks, and their behavioral responses were compared. Krill-scented vegetable oil slicks were highly attractive to some but not all procellariiform species foraging in this area (p < 0.001, G-test). Cape petrels Daption capense and southern giant petrels Macronectes g~ganteus appeared at krill-scented slicks within l rnin, whereas black-browed albatrosses Diomedea melanophris appeared within 3 min. Cape petrels D, capense showed the strongest attraction: these birds were observed as much as 5 times as frequently at krill-scented slicks as compared to unscented control slicks (p < 0.001, G-test), whde storm-petrels (Oceanites oceanicus and Fregetta tropica] and Antarctic Fulmars Fulmarus glacialoides responded in equal numbers to krill-scented and unscented slicks. When considered with respect to previously published findings, these results suggest a greater complex~ty in the significance of odors to the foraging ecology of different tube-nosed species than has commonly been assumed.

On the Olfactory Anatomy in an Archaic Whale (Protocetidae, Cetacea) and the Minke Whale Balaenoptera acutorostrata (Balaenopteridae, Cetacea)

“…Thewissen et al (2011) hypothesize that bowheads, Balaena mysticetus use olfaction to detect conspecific mates and/ or more likely clouds of the plankton on which they feed. Evidently, krill give off a peculiar odor, partly caused by dimethylsulfide and pyridines (Nevitt, 1999). Minke whales have a much more diverse diet (Perrin et al, 2009), in which case, if they are using olfaction in their pursuit of prey, it is not known what (other) airborne cues they are responding to.…”

Scale-dependent habitat selection by a nearshore seabird, the marbled murrelet, in a highly dynamic upwelling system

“…Thus, seabirds appear to make hierarchical decisions -first to find large-scale and then to locate small-scale habitat features that aggregate prey (Russell et al 1992, Weimerskich et al 1997, Nevitt & Veit 1999, Fauchald et al 2000. Cues that may help seabirds select profitable foraging habitat and then prey within that habitat include water temperatures (Ribic & Ainley 1997), thermal fronts (Hoefer 2000), pycnocline depth (Ribic & Ainley 1997), olfactory cues (Nevitt 1999), the presence of other birds (Lachmann et al 2000), and the ability to visually locate prey (Gaston & Jones 1998). During the breeding season, nesting seabirds have the additional energetic constraint of traveling between colonies and foraging sites (Hull et al 2001).…”

Exploitation of mesoscale oceanographic features by grey-headed albatross Thalassarche chrysostoma in the southern Indian Ocean

“…Studies have shown that seabirds are predictably concentrated at physical oceanographic features of different spatial scales, from tidal fronts through mesoscale eddies to latitudinal frontal systems, which all display increased prey availability (Haney et al 1995, Pakhomov & McQuaid 1996, Rodhouse et al 1996, Hunt et al 1999. Once at an area of enhanced biological productivity, procellariforms may use odor trails or visual clues to locate concentrations of prey (Nevitt 1999).…”