Many behavioural reactions of animals including motor ones are asymmetric and are associated with unequal input of the left and right hemispheres of the brain to the analysis of incoming information. Motor asymmetries are widespread among vertebrate and invertebrate animals. Forelimb preferences have been studied in many vertebrate species. The movements of unpaired appendages become the subjects of an investigation of the functional asymmetries less often. Here we performed a preliminary estimation of one-side population bias
of neck-resting position of the barnacle goose Branta leucopsis. The study was conducted in the four districts located along the coastline and on the islands in the centre of Helsinki city in Finland. On the walking routes, the asymmetrical neck-resting position under the left or right wing was recorded for resting and sleeping birds once for each individual. A total of 15 routes were taken and the neck-resting position of 874 individuals was analyzed. Right-side neck-resting preference was observed in all samples. As a possible cause of such a
neck-resting preference, it is assumed that during the rest when the bird’s head is under the wing the opposite eye can be used to monitor the surroundings and promptly react in the case of the appearance of predators or humans. In this case, the revealed one-side population bias demonstrates lateralization of vigilance and implies the left-eye (right-hemisphere) control of the responses to potential threats. This work was supported by RSF grant (no.19-14-00119).