Abstract: Past studies of galliform anti-predator behavior show that they discriminate between aerial and ground predators, producing distinctive, functionally referential vocalizations to each class. Within the category of aerial predators, however, studies using overhead models, video images and observations of natural encounters with birds of prey report little evidence that galliforms discriminate between different raptor species. This pattern suggests that the aerial alarm response may be triggered by general features of objects moving in the air. To test whether these birds are also sensitive to more detailed differences between raptor species, adult chickens with young were presented with variously sized trained raptors (small, intermediate, large) under controlled conditions. In response to the small hawk, there was a decline in anti-predator aggression and in aerial alarm calling as the young grew older and less vulnerable to attack by a hawk of this size. During the same developmental period, responses to the largest hawk, which posed the smallest threat to the young at all stages, did not change; there were intermediate changes at this time in response to the middle-sized hawk. Thus the anti-predator behavior of the adult birds varied in an adaptive fashion, changing as a function of both chick age and risk. We discuss these results in light of current issues concerning the cognitive mechanisms underlying alarm calling behavior in animals.

Abstract: We report experiments based on a novel test in domestic chicks ( Gallus gallus), designed to examine the encoding of two different geometric features of an enclosed environment: relative lengths of the walls and amplitude of the corners. Chicks were trained to search for a food reward located in one corner of a parallelogram-shaped enclosure. Between trials, chicks were passively disoriented and the enclosure was rotated, making reorientation possible only on the basis of the internal spatial structure of the enclosure. In order to reorient, chicks could rely on two sources of information: the relative lengths of the walls of the enclosure (associated to their left-right sense order) and the angles subtended by walls at corners. Chicks learned the task choosing equally often the reinforced corner and its rotational equivalent. Results of tests carried out in novel enclosures, the shapes of which were chosen ad hoc (1) to induce reorientation based only on the ratio of walls lengths plus sense (rectangular enclosure), or (2) to induce reorientation based only on corner angles (rhombus-shaped enclosure), suggested that chicks encoded both features of the environment. In a third test, in which chicks faced a conflict between these geometric features (mirror parallelogram-shaped enclosure), reorientation seemed to depend on the salience of corner angles. These results shed light on the elements of the environmental geometry which control spatial reorientation, and broaden the knowledge on the geometric representation of space in animals.

Abstract: Animal welfare, or well-being, is a social issue with ethical, scientific, political, and aesthetic properties. Answering questions about the welfare of animals requires scientific definition, assessment, solutions, and public acceptance. With respect to the actual well-being of the animal, most issues are centered on how the animal “feels” when managed within a specific level of confinement, during special agricultural practices (e.g., tail docking, beak trimming, etc.) and handling. Questions of this nature may require exploration of animal cognition, motivation, perception, and emotional states in addition to more commonly recognized indicators of well-being. Several general approaches have emerged for solving problems concerning animal well-being in intensive production systems: environmental, genetic, and therapeutic. Environmental approaches involve modifying existing systems to accommodate specific welfare concerns or development of alternative systems. Genetic approaches involve changing the behavioral and (or) physiological nature of the animal to reduce or eliminate behaviors that are undesirable within intensive system. Therapeutic approaches of a physical (tail docking, beak trimming) and physiological (drug and nutritional therapy) nature bring both concern and promise with regard to the reduction of confinement stress. Finally, the recent focus on commodity quality assurance programs may indirectly provide benefits for animal well-being. Although research in the area of animal well-being will provide important information for better animal management, handling, care, and the physical design of intensive production systems there is still some uncertainty regarding public acceptance. The aesthetics of modern intensive production systems may have as much to do with public acceptance as with science.

Abstract: Lateralization of the brain appeared early in evolution and many of its features appear to have been retained, possibly even in humans. We now have a considerable amount of information on the different forms of lateralization in a number of species, and the commonalities of these are discussed, but there has been relatively little investigation of the advantages of being lateralized. This article reports new findings on the differences between lateralized and nonlateralized chicks. The lateralized chicks were exposed to light for 24 h on day 19 of incubation, a treatment known to lead to lateralization of a number of visually guided responses, and the nonlateralized chicks were incubated in the dark. When they were feeding, the lateralized chicks were found to detect a stimulus resembling a raptor with shorter latency than nonlateralized chicks. This difference was not a nonspecific effect caused by the light-exposed chicks being more distressed by the stimulus. Instead, it appears to be a genuine advantage conferred by having a lateralized brain. It is suggested that having a lateralized brain allows dual attention to the tasks of feeding (right eye and left hemisphere) and vigilance for predators (left eye and right hemisphere). Nonlateralized chicks appear to perform these dual tasks less efficiently than lateralized ones. Reference is made to other species in discussing these results.