Forty years of olfactory navigation in birds

Abstract

SummaryForty years ago, Papi and colleagues discovered that anosmic pigeons cannot find their way home when released at unfamiliar locations. They explained this phenomenon by developing the olfactory navigation hypothesis: pigeons at the home loft learn the odours carried by the winds in association with wind direction; once at the release site, they determine the direction of displacement on the basis of the odours perceived locally and orient homeward. In addition to the old classical experiments, new GPS tracking data and observations on the activation of the olfactory system in displaced pigeons have provided further evidence for the specific role of olfactory cues in pigeon navigation. Although it is not known which odours the birds might rely on for navigation, it has been shown that volatile organic compounds in the atmosphere are distributed as fairly stable gradients to allow environmental odour-based navigation. The investigation of the potential role of olfactory cues for navigation in wild birds is still at an early stage; however, the evidence collected so far suggests that olfactory navigation might be a widespread mechanism in avian species.

Pigeon navigation: exposure to environmental odours prior release is sufficient for homeward orientation, but not for homing

“…For each direction, two releases were performed at the same release site, except for releases from East, which were performed in two sites at different distances from the same direction (Empoli and Montespertoli). The sample size tested for each direction was chosen on the basis of similar studies on homing pigeons (see Gagliardo, 2013). However, since the Arnino field station is located about 5 km from the Tyrrhenian coast, the release sites could not be balanced in all compass directions.…”

“…Since Papi et al (1971) showed that anosmic homing pigeons were dramatically impaired at homing, a large body of evidence has supported the role of olfactory cues in navigation (summarised in Wallraff, 2005;Gagliardo, 2013). The olfactory navigation hypothesis predicts that pigeons are able to associate environmental odours carried by the winds with the directions from which they blow at the home area.…”

Navigating virtual mazes: The benefits of audiovisual landmarks

“…Although our study focusses on audiovisual environments, it is of interest that multisensory navigation is likely to also involve the olfactory and tactile sensory systems. It has been known for a longer time that ants can use olfactory information in order to locate their nest entrance [20] and that pigeons use gradients of volatile organic compounds in the atmosphere for environmental odor-based navigation [21]. But it has only recently been shown that humans have a residual directional smelling ability and process spatial information in the olfactory system [22].…”

An amazing discovery: bird navigation based on olfaction

“…After several years of continued research, it was possible to enumerate 17 different kinds of experiment that yielded a coherent collection of findings supporting olfaction-based navigation (Wallraff, 2005b). The principal results were also confirmed in a number of wildliving bird species, even for distances as great as 800 km (for details and further references see Papi, 1986Papi, , 1989Papi, , 1991Wallraff, 2004Wallraff, , 2005aGagliardo, 2013;Gagliardo et al, 2013).…”