Homing performances of inexperienced and directionally trained pigeons subjected to olfactory nerve section

Abstract

Pigeons not experienced in homing and subjected to olfactory nerve section are generally found to be unable to home from short distances. In nine successive releases from different localities at 3.3 to 11.8 km from the loft, 15 out of 19 experimental birds were lost as well as 2 out of 40 control birds. The homing capacity improves when the birds are released from familiar localities on a line along which they have been trained before undergoing nerve section, but they still perform very poorly in later releases from unfamiliar localities outside the training line. 11 experimental birds showed fairly good performances from a familiar locality on the training line at 43.4 km from the loft (10 returned within the same day of the release, at an average speed of 32 km/h). Only one of these birds was able to home within the same day in a later release in an unfamiliar locality outside the training line at 34.9 km from the loft. Five other birds of this group homed one or more days later, and the remaining five were lost. The initial orientation was poorer amongst the experimental birds. More of the inexperienced experimentals landed near the release point. As the experiments show that olfactory nerve section causes no disturbances in general behaviour and homing drive, it is concluded that olfaction plays an important and specific role in the homing mechanism of pigeons.