Sensitivity to dimethyl sulphide suggests a mechanism for olfactory navigation by seabirds

Abstract

Petrels, albatrosses and other procellariiform seabirds have an excellent sense of smell, and routinely navigate over the world's oceans by mechanisms that are not well understood. These birds travel thousands of kilometres to forage on ephemeral prey patches at variable locations, yet they can quickly and efficiently find their way back to their nests on remote islands to provision chicks, even with magnetic senses experimentally disrupted. Over the seemingly featureless ocean environment, local emissions of scents released by phytoplankton reflect bathymetric features such as shelf breaks and seamounts. These features suggest an odour landscape that may provide birds with orientation cues. We have previously shown that concentrated experimental deployments of one such compound, dimethyl sulphide (DMS), attracts procellariiforms at sea, suggesting that some species can use it as a foraging cue. Here we present the first physiological demonstration that an Antarctic seabird can detect DMS at biogenic levels. We further show that birds can use DMS as an orientation cue in a non-foraging context within a concentration range that they might naturally encounter over the ocean.

Figure 1

Physiological and behavioural responses to DMS. (a) Mean change in heart rate (expressed in beats min⁻¹±s.e.) across 10 prions tested in response to DMS or control (see §2). (b) Orientation to DMS in a Y-maze. Each histogram shows the percentage of birds that chose DMS, control (C) or did not chose (NC) in Y-maze tests performed at Ile Verte.