Procellariiforms

In addition to their role in chemical defense, DMSP-lyase products may also function as chemical cue in more complex trophic cascades. In the natural environment DMS-production is related to zooplankton herbivory [60] and can thus act as an indicator for the availability of food for planktivorous birds. Indeed, some Antarctic Procellariiform seabirds can detect DMS (22) and are highly attracted to the cue, as was shown with DMS-scented oil slicks on the ocean surface [61]. The odors released during zooplankton grazing (DMS) as well as those of zooplankton itself (e.g., trimethylamine and pyrazines) are attractive to birds [62], thus assisting vertebrate search behavior. 

Another experiment used cod liver oil, crude krill extract, and the krill odor components trimethylamine and pyrazine, with phenylethanol (rose odor) as control. Several procellariiform species were attracted to krill extract. The krill odor components attracted giant petrels, cape petrels, blue petrels, Antarctic petrels, Kerguelen petrels, and black-browed albatrosses. Cape petrels were more attracted to trimethylamine than to pyrazine and cod liver oil hut blue petrels responded most to cod liver oil (Nevitt, 1999). 

Antarctic procellariiform seabirds can smell krill. Antarctic Journal of the USA 29, 168-169. 

The ecological and evolutionary challenges of procellariiform olfaction. In Chemical Signals in Vertebrates, vol. 4, ed. D. Duvall, D. Miiller-Schwarze and R. M. Silverstein, pp. 357-368. New York Plenum. 

Nevitt GA, Veit RR, Kareiva P (1995) Dimethyl sulfide as a foraging cue for Antarctic Procellariiform seabirds. Nature 376 680-682... 

Figure 1. Olfactory behaviors. (A) Procellariifomis commute between nesting colonies and areas of high primary productivity where prey is likely to be found. (B) Procellariiforms locate prey patches (circled P s) and home burrows (circled B s) in part by tracking odors upwind. Diagrams not drawn to scale.

Nevitt, G. A., 2001, Mechanisms of olfactory foraging in procellariiform seabirds, in Chemical Signals in Vertebrates, vol. 9, A. Marchlewska-Koj, J. L. Lepri and D. Muller-Schwarze, eds.. New York, Plenum Publishing Corp, pp. 27-33. 

Nevitt, G. A., in press, Ol ctory foraging strategies of procellariiform seabirds, in Proceedings of the 23" International Ornithological Congress, Beijing China. 

We caution undue optimism regarding the quick discovery of simple chemical signals for an artificial lure system, especially if the candidate lures are compounds that are selected on the basis of human perception. Human perception is likely to be an inappropriate basis for sensory studies of other animals. For example, many procellariiform birds are attracted to the odors of a variety of fish oils and fish by-products (Clark and Shah, 1992). To humans, these food items have a distinctly fishy smell largely attributable to the... 

The probably universal occurrence of large olfactory mucosae and bulbs in three of the four procellariiform families comprising over 90% of the species compels careful behavioral study. These birds unquestionably are reacting to odors in significant ways. How does such dependence interact with reliance on visual and other sensory cues The prominence of their olfactory equipment implies some degree of functional dominance for smell. Our present understanding of olfactory mechanisms does not tell us what specific advantages reside in more, rather than less, olfactory tissue. 

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