Abstract
Dominance hierarchies confer benefits to group members by decreasing the incidences of physical conflict, but may result in certain lower ranked individuals consistently missing out on access to resources. Here, we report a linear dominance hierarchy remaining stable over time in a closed population of birds. We show that this stability can be disrupted, however, by the artificial mass loading of birds that typically comprise the bottom 50% of the hierarchy. Mass loading causes these low-ranked birds to immediately become more aggressive and rise-up the dominance hierarchy; however, this effect was only evident in males and was absent in females. Removal of the artificial mass causes the hierarchy to return to its previous structure. This interruption of a stable hierarchy implies a strong direct link between body mass and social behaviour and suggests that an individual's personality can be altered by the artificial manipulation of body mass.
Highlights
Many animals live and travel in groups [1,2]
150 Upon application of the artificial mass, the dominance hierarchy changed significantly but remained linear; the dominance hierarchy observed when nine birds were artificially weighted was significantly different than all seven non-weighted hierarchies (Spearman’s Rho, ρ, range 0.04-0.09; table 2)
Over a 31-month period, the dominance hierarchy of the pigeon group did not significantly 190 change, with individuals retaining their position within the hierarchy throughout the experimental period
Summary
Many animals live and travel in groups [1,2]. The benefits of group living can include enhanced vigilance and predator detection [1,2], energetic saving through positive aero- or hydro dynamic interactions [3,4] and increased foraging efficiency [5,6]. 85 Using a captive flock of homing pigeons (Columba livia), we tested whether (a) group dominance hierarchies were stable over successive years in a closed population, (b) whether any hierarchical structure was directly related to body mass, and, (c) if linear hierarchies were stable and correlated with body mass, whether they could be disrupted by artificial instantaneous manipulations of body mass. Nineteen months after the commencement of the study, the nine birds that constituted the bottom positions in the hierarchy were artificially weighted. 120 The repeatability over non-weighted sessions of (i) aggression via David’s score and (ii) body mass was assessed by calculating the intraclass correlation coefficient using the rptR package in R [20,23].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
