Olfaction and the homing ability of pigeons raised in a tropical area in Brazil

Abstract

Several workers have investigated the effect of anosmia on pigeon navigation in different geographical locations because it has been suggested that homing behavior is based on different cues, such as olfactory cues, the Earth's magnetic field or infrasound, and that in the absence of one cue another would be used. In this situation, no cue is universally indispensable, including olfactory ones. In order to extend such observations to a novel biome, we observed the behaviour of 192 young inexperienced birds raised in southeastern Brazil, a tropical area where olfactory tests had never been run before. The birds were released from eight symmetrically distributed sites 17 to 44 km from the loft. Half of these birds (experimentals) had been made temporarily anosmic by washing their olfactory mucosae with 4% solution of ZnSO4 the day before release, while controls were treated with Ringer solution. The results of release tests showed that anosmia totally impaired the navigational performance of experimental birds, which were unable to home from sites at relatively short distances from home (34-44 km) and whose pooled initial bearings produced a (negative) homeward component not significantly different from 0. Homing performance of controls was significantly better, and their pooled vanishing bearings had a significant homeward component, in spite of much scatter in individual releases. We conclude that pigeon homing in the study area depends on olfactory information, even though local environmental conditions in the interior of the State of Sao Paulo, as in several other parts of the world, do not appear to be as favorable as Italy for the development of efficient olfactory navigation.

The G Protein–Coupled Receptor Subset of the Chicken Genome

“…It is not known which ligands these novel proteins recognize, but it is likely that these ligands are some kind of volatile airborne substance. Several studies have addressed the deficient homing ability in anosmic birds; these studies indicate that birds use the olfactory system for navigation, particularly in unknown terrain [ 71 – 73 ]. Birds apparently also use the olfactory system for discriminating between individuals and finding their nests, for finding food, and for avoiding toxic insects and dangerous predators [ 74 – 76 ].…”

Forty years of olfactory navigation in birds

“…Interestingly, it has been observed that orientation and homing performance of pigeons belonging to the same colony varied according to season, as the birds performed better in spring-summer than autumn-winter (Foà et al, 1984). Many experiments conducted in different countries tested whether the nature of the cues used for navigation was different depending on the geographical region the birds were raised (Benvenuti et al, 1998;Benvenuti and Ranvaud 2004;Gagliardo et al, 2000). These experiments were stimulated by the idea that pigeons have a multi-cue system, and the nature of the cues preferentially used for navigation might depend on the availability of stimuli of a certain kind during map learning (Walcott, 1996).…”

Diversity in olfactory bulb size in birds reflects allometry, ecology, and phylogeny

“…It has long been thought that olfaction plays some role in navigation and homing in birds, whereby birds deduce positional information from airborne odors carried by winds to find their way home (e.g., Papi, 1976 , 1982 ; Wallraff, 2004 , 2013 ). Navigation by olfactory cues has been shown in many species ranging from swifts, Apus apus ( Fiaschi et al, 1974 ), starlings, Sturnus vulgaris ( Wallraff et al, 1995 ), catbirds Dumetella carolinensis ( Holland et al, 2009 ), pigeons Columba livia ( Papi, 1976 ; Wiltschko and Wiltschko, 1992 ; Benvenuti and Ranvaud, 2004 ) and many seabirds ( Gagliardo et al, 2013 ). However, there is some skepticism with respect to olfactory mediated navigation (e.g., Gould, 2009 ; Jorge et al, 2009 , 2010 ; Wiltschko, 2012 ; Blaser et al, 2013 ; Phillips and Jorge, 2014 ; Wallraff, 2014 ), therefore determining if migration behavior correlates with relatively large OBs might shed some light on this argument.…”