March/April 2025

22 – Purebred PIGEON DOMINANCE IN PIGEONS: WHO RULES THE ROOST? The term “pecking order” was first used in 1921 by a Norwegian zoologist who described dominance hierar- chies in chickens. He observed that chickens understand their place in the hierarchy. They peck flock mates who have lower status and in turn are pecked by those with higher rank. This type of ordered dominance is called a linear hierarchy. Dominance hierarchies occur in chickens, pigeons, and numerous other animals that live in groups. Group living conveys important benefits including more eyes to spot predators and locate food. But living in groups comes with a cost: increased competition for resources such as food and shelter. The increased competition results in increased aggression. In order to reduce aggression among members of a group, many species make use of dominance hierarchies. Once the hierarchy is established, each animal knows its place. As a result, time spent dealing with physical con- flict is reduced and more time can be devoted to important activities such as feeding, grooming, and vigilance. A WEIGHTING GAME In three studies, researchers at the Royal Veterinary College of the University of London identified factors that appear to contribute to dominance in pigeons. In the first study, a captive flock of homing pigeons was observed to have a stable dominance hierarchy during a 31-month period. The larger birds were at the top of the hierarchy and the smaller birds were at the bottom. The larger birds showed more aggression and were first in line at feeding time. But when the researchers affixed small weights to the smaller birds, the hierarchy was altered. The birds with the added weights became more aggressive and moved to the top of the hierarchy. They remained at the top until the weights were removed. Without the added weights, they showed less aggression and fell to the bottom of the hierarchy once again and the hierarchy returned to its previous structure. The results of this study suggest there is a strong link between body mass and dominance in pigeons. Interestingly, only males responded to the addition of weights by becoming more aggressive and rising to the top of the hierarchy. Females did not respond in this way. This sex-specific response may be due to competition for females. In other words, female pigeons may prefer as mates males from the top of the dominance hierarchy. RULED BY A DESPOT In the second study, the behavior of two captive flocks of homing pigeons was observed and the domi- nance hierarchy of each flock was determined. Then the movements of each bird were measured using acceler- ometry loggers. The researchers discovered that in both flocks the most dominant bird was significantly more active than its flock mates, on average 39% more than the bird with the next highest degree of movement. A big difference. In both flocks, all birds other than the domi- nant bird moved at levels not significantly different from one another. The results of this study suggest that being the dominant pigeon involves a cost in the form of energy expenditure that is not incurred by pigeons of lower rank. The researchers proposed two potential explanations for these results. It may be that dominant pigeons are more active because they must initiate aggressive interactions in order to remain at the top of the hierarchy. Doing so may keep subordinate pigeons in their place, thus mini- mizing overall aggression in the flock. A second potential explanation is that dominant pigeons may have higher basal metabolic rates, and their greater energy require- ments may drive them to be aggressive in order to obtain adequate access to food. In any case, this study paints a picture of a despotic society, with a dominant pigeon spending high levels of energy to maintain his rank and to police the flock. RULED FROM ABOVE In the third study, researchers looked at the rela- tionship between dominance and perch preference in a captive flock of homing pigeons. First, the dominance hierarchy of the flock members was determined. Then the perch preferences of each pigeon were noted. The researchers found that dominant pigeons consistently PIGEON BEHAVIOR A Series of Articles by Mike McKaig Original Art by Trent Smith