Giraldeau, L. - A., & Lefebvre, L. (1986). Exchangeable producer and scrounger roles in a captive flock of feral pigeons: a case for the skill pool effect. Anim. Behav., 34(3), 797–803.
Abstract: We investigated the foraging producer-scrounger system of a captive flock of feral pigeons (Columba livia) by monitoring the number of food patches each individual produced. In one experiment, three different patch types were tested on the whole flock while, in a second, flock composition was varied for one patch type. In all cases we found non-uniform distributions of the number of patches produced per individual, which suggests the existence of producer and scrounger roles. This result could not be explained by either dominance or variability in individual learning ability. Individuals switched roles in response to changes both in food patch type and flock composition. These results are discussed in light of the skill pool hypothesis, which suggests that, in a group, different foraging specialists will profit by parasitizing each other's food discoveries.
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Blakeman, N. E., & Friend, T. H. (1986). Visual discrimination at varying distances in Spanish goats. Appl Anim Behav Sci, 16.
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Crowell-Davis, S. L. (1986). Spatial relations between mares and foals of the Welsh pony (Equus caballus). Anim Beh, 34(4), 1007–1015.
Abstract: Welsh pony mares and foals (Equus caballus) were usually found to be within 1 or 5 m of each other during the first week of the foal's life and gradually spent more time at greater distances as the foals became older. There was an overall levelling of the trend during the 9th-15th weeks of life of the foal, followed by a second period of change during weeks 16-24. Through weeks 21-24, mares and foals spent at least half of their time within 5 m of each other. Proximity was primarily due to foal activity except during foal recumbency. During the first 8 weeks of the foal's life, a mare remained close by when it was recumbent, either by grazing in a circle around it or by standing upright beside it. Mares and foals were most likely to be close together when they were resting upright with the other ponies in the herd and most likely to be far apart when the foal was playing. Similarities in patterns of spatial relationship between the foals of a given mare were demonstrated. There was no difference between colts and filies in the development of independence.
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Houpt, K. A. (1986). Stable vices and trailer problems. Vet Clin North Am Equine Pract, 2(3), 623–633.
Abstract: Stable vices include oral vices such as cribbing, wood chewing, and coprophagia, as well as stall walking, weaving, pawing, and stall kicking. Some of these behaviors are escape behaviors; others are forms of self-stimulation. Most can be eliminated by pasturing rather than stall confinement. Trailering problems include failure to load, scrambling in the moving trailer, struggling in the stationary trailer, and refusal to unload. Gradual habituation to entering the trailer, the presence of another horse, or a change in trailer type can be used to treat these problems.
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Crowell-Davis, S. L., & Houpt, K. A. (1986). Maternal behavior. Vet Clin North Am Equine Pract, 2(3), 557–571.
Abstract: Parturition in mares is rapid and is followed by a brief period of sensitivity to imprinting on a foal. There is large individual variation in normal maternal style, but normal mothers actively defend their foal, remain near the foal when it is sleeping, tolerate or assist nursing, and do not injure their own foal. Disturbance of a mare and foal during the early imprinting period can predispose a mare to rejection of her foal; therefore, it should be avoided. There are a variety of forms of foal rejection and numerous etiologies. Therefore, each case should be evaluated individually.
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Crowell-Davis, S. L., & Houpt, K. A. (1986). Techniques for taking a behavioral history. Vet Clin North Am Equine Pract, 2(3), 507–518.
Abstract: A thorough behavioral history is essential for adequate assessment of a given case. In reviewing the chief complaint, a description of what actually happened, rather than the owner's interpretation of what happened, is required. Other behavior problems, environment, rearing history, and training need to be reviewed. Sample question sets for some common problems are given.
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de Waal, F. B. (1986). The integration of dominance and social bonding in primates. Q Rev Biol, 61(4), 459–479.
Abstract: Social dominance is usually viewed from the perspective of intragroup competition over access to limited resources. The present paper, while not denying the importance of such competition, discusses the dominance concept among monkeys and apes in the context of affiliative bonding, social tolerance, and the reconciliation of aggressive conflicts. Two basic proximate mechanisms are supposed to provide a link between dominance and interindividual affiliation, namely, formalization of the dominance relationship (i.e., unequivocal communication of status), and conditional reassurance (i.e., the linkage of friendly coexistence to formalization of the relationship). Ritualized submission is imposed upon losers of dominance struggles by winners; losers are offered a “choice” between continued hostility or a tolerant relationship with a clearly signalled difference in status. If these two social mechanisms are lacking, aggression is bound to have dispersive effects. In their presence, aggression becomes a well-integrated, even constructive component of social life. In some higher primates this process of integration has reached the stage where status differences are strongly attenuated. In these species, sharing and trading can take the place of overt competition. The views underlying this “reconciled hierarchy” model are only partly new, as is evident from a review of the ethological literature. Many points are illustrated with data on a large semi-captive colony of chimpanzees (Pan troglodytes), particularly data related to striving for status, reconciliation behavior, and general association patterns. These observations demonstrate that relationships among adult male chimpanzees cannot be described in terms of a dichotomy between affiliative and antagonistic tendencies. Male bonding in this species has not been achieved by an elimination of aggression, but by a set of powerful buffering mechanisms that mitigate its effects. Although female chimpanzees do exhibit a potential for bonding under noncompetitive conditions, they appear to lack the buffering mechanisms of the males.
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de Waal, F. B., & Luttrell, L. M. (1986). The similarity principle underlying social bonding among female rhesus monkeys. Folia Primatol (Basel), 46(4), 215–234.
Abstract: Twenty adult female rhesus monkeys (Macaca mulatta) were observed over a three-year period. They lived in a mixed captive group with kinship relations known for three generations. The study's aim was to test Seyfarth's [J. theor. Biol. 65: 671-698, 1977] model of rank-related grooming and to investigate two other possible determinants of social bonding, i.e. relative age and the group's stratification into two social classes. Data on affiliation, coalitions, and social competition were collected by means of both focal observation and instantaneous time sampling. Whereas certain elements of the existing model were confirmed, its explanatory principles were not. Social competition did not result in more contact among close-ranking females (the opposite effect was found), and the relation between affiliative behavior and coalitions was more complex than predicted. Based on multivariate analyses and a comparison of theoretical models, we propose a simpler, more encompassing principle underlying interfemale attraction. According to this 'similarity principle', rhesus females establish bonds with females whom they most resemble. The similarity may concern genetical and social background, age, hierarchical position and social class. Effects of these four factors were independently demonstrated. The most successful model assumed that similarity factors influence female bonding in a cumulative fashion.
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Zentall, S. S., & Zentall, T. R. (1986). Hyperactivity ratings: statistical regression provides an insufficient explanation of practice effects. J Pediatr Psychol, 11(3), 393–396.
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Zentall, T. R., Jackson-Smith, P., Jagielo, J. A., & Nallan, G. B. (1986). Categorical shape and color coding by pigeons. J Exp Psychol Anim Behav Process, 12(2), 153–159.
Abstract: Categorical coding is the tendency to respond similarly to discriminated stimuli. Past research indicates that pigeons can categorize colors according to at least three spectral regions. Two present experiments assessed the categorical coding of shapes and the existence of a higher order color category (all colors). Pigeons were trained on two independent tasks (matching-to-sample, and oddity-from-sample). One task involved red and a plus sign, the other a circle and green. On test trials one of the two comparison stimuli from one task was replaced by one of the stimuli from the other task. Differential performance based on which of the two stimuli from the other task was introduced suggested categorical coding rules. In Experiment 1 evidence for the categorical coding of sample shapes was found. Categorical color coding was also found; however, it was the comparison stimuli rather than the samples that were categorically coded. Experiment 2 replicated the categorical shape sample effect and ruled out the possibility that the particular colors used were responsible for the categorical coding of comparison stimuli. Overall, the results indicate that pigeons can develop categorical rules involving shapes and colors and that the color categories can be hierarchical.
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