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Bamford, A. J., Monadjem, A., & Hardy, I. C. W. (2010). Associations of Avian Facial Flushing and Skin Colouration with Agonistic Interaction Outcomes. Ethology, , no-no.
Abstract: Abstract Facial flushing, a colour change caused by variation of blood flow through highly vascularized skin, has been observed in taxonomically diverse bird species but the function of the behaviour has not been assessed. Lappet-faced vultures, Aegypius tracheliotos, have unfeathered heads that can rapidly flush from pink to dark red, and this has been hypothesized to indicate contest ability in vulture gatherings. We show that adults with flushed heads won most interactions against those with pale heads. A previously unnoticed colour variation of the throat, visible only when the head is flushed, was also related to the outcome of interactions: blue-throated adults participated in, and won, more interactions than red-throated adults. We suggest that the non-fixed groups of which lappet-faced vulture populations consist promote the evolution of signals of dominance that can be adjusted extremely rapidly.
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Baer, K. L., Potter, G. D., Friend, T. H., & Beaver, B. V. (1983). Observation effects on learning in horses. Appl. Animal. Ethol., 11(2), 123–129.
Abstract: Sixteen horses, divided into 2 groups of 8, were used to study observational learning in horses. One group served as controls while the other group served as the treated group (observers). Observers were allowed to watch a correctly performed discrimination task for 5 days prior to testing their learning response using the same task. Discrimination testing was conducted on all horses daily for 14 days, with criterion set at 7 out of 8 responses correct with the last 5 consecutively correct. The maximum number of trials performed without reaching criterion was limited to 20 per day. Mean trials to criteria (MT) by group were: control, 11.25; observer, 10.70. Mean error (ME) scores were: control, 2.37; observer, 2.02. Average initial discrimination error scores were 11.13 for control and 10.38 for observers (P < 0.10). Asymptote was reached by Day 8 for both control and observer groups. Analysis of variance with repeated measures showed an extreme-day effect indicative of learning (P < 0.01), with non-significant differences in learning rate between experimental groups. Whether the initial ability of the horses to perform a discrimination learning task was enhanced by observation of other horses' performance of that task was not obvious from these data.
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Arnold Gw, G. A. (1982). Ethogram of agonistic behaviour for thoroughbred horses. Appl. Animal. Ethol., 8(1), 5–25.
Abstract: Social interactions between individual horses were observed in two herds each comprising a stallion and a number of mares. In one herd, the animals were observed whilst grazing and resting; in the other, nearest neighbours were recorded when the animals were grazing, and social interactions were noted when the animals were feeding on hay.
In both herds, the horses showed marked preferences for the company of specific individuals when they were grazing. In one herd, the associations were mainly between individuals that had been associated prior to being put in the herd. In the other herd, this was not the case. A new statistic was produced for testing for specific company preference. In both herds, the stallion was dominant over all mares and never received any aggression.
The complete social hierarchy could not be determined for the herd which was observed only when grazing because social contact was restricted to that within groups or pairs that associated together. In the herd to which hay was fed, a non-linear hierarchy existed. Statistics were produced to quantify both the general level of dominance of a horse and its specific dominance or subordination to every other horse. It is suggested that these statistics, and one for quantifying the general aggressiveness of a horse, could be widely used.
A principal component analysis allowed the horses to be characterised socially according to aggressiveness, their attitude to other horses and their attractiveness to other horses.
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Amandine Ramseyer, Bernard Thierry, Alain Boissy, & Bertrand Dumont. (2009). Decision-making Processes in Group Departures of Cattle. Ethology, 115(10), 948–957.
Abstract: To keep social cohesiveness, group-living animals have to reach consensus decisions through recruitment processes. This implies that decision-making depends on the behaviours and social relationships of several group members at different stages of movements. We tested these assumptions in a group of fifteen 18-mo-old Charolais heifers (Bos taurus) at pasture, in which two observers continuously videotaped social interactions and group departures after resting periods. These departures were preceded by a phase of preparation characterized by an increase in activity. The number of heifers participating to a movement increased with the number of group members oriented in the direction of the movement before departure. The first moving animal also recruited a higher number of mates when it had a greater number of close neighbours, the first individuals to follow being mainly its preferential partners. Coercive interactions such as pressing behaviours were observed within the 5 min preceding or following departure. After departure, the numbers of walks and restarts of the first two movers were still operative in recruiting others. The frequency of pauses of the first mover was significantly higher when it was not followed, meaning that it adjusted its behaviour to that of other group members. Decision-making was distributed among group members, with any individual being liable to move first. The behaviour of cows and their spatial distribution before departure, at departure and after departure significantly affected the number of participants in the movement, demonstrating that decision-making was time-distributed in the studied cattle group.
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