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Kirkpatrick, J. F., & Turner, A. (2002). Reversibility of action and safety during pregnancy of immunization against porcine zona pellucida in wild mares (Equus caballus). Reprod Suppl, 60, 197–202.
Abstract: Contraceptive management of publicly valued wildlife species requires safeguards to ensure that these populations are preserved in a healthy state. In addition, reversibility of contraceptive effects and safety in pregnant animals are major concerns. A population of wild horses has been immunized against porcine zona pellucida (PZP) over a 12 year period on Assateague Island National Seashore, MD (ASIS). Mares initially received one or two 65 microg inoculations and once a year 65 microg booster inoculations, all delivered by dart. All young mares aged > 2 years were treated with PZP for 3 consecutive years regardless of whether they have bred successfully and they were then removed from treatment until they had foaled. All mares vaccinated for 1 or 2 consecutive years became fertile again and 69% of mares treated for 3 consecutive years returned to fertility. All five mares treated for 4 or 5 consecutive years have also returned to fertility, but over longer periods of time. Mares treated for 7 consecutive years have not returned to fertility, but several, while still infertile, have started ovulating again. There was no difference in survival rates between foals born to treated and untreated mares, and PZP treatment of pregnant mares did not affect subsequent fertility of their female offspring.
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Dorrance, B. R., & Zentall, T. R. (2002). Imitation of conditional discriminations in pigeons (Columba livia). J Comp Psychol, 116(3), 277–285.
Abstract: In the present experiments, the 2-action method was used to determine whether pigeons could learn to imitate a conditional discrimination. Demonstrator pigeons (Columba livia) stepped on a treadle in the presence of 1 light and pecked at the treadle in the presence of another light. Demonstration did not seem to affect acquisition of the conditional discrimination (Experiment 1) but did facilitate its reversal of the conditional discrimination (Experiments 2 and 3). The results suggest that pigeons are not only able to learn a specific behavior by observing another pigeon, but they can also learn under which circumstances to perform that behavior. The results have implications for proposed mechanisms of imitation in animals.
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Peake, T. M., Terry, A. M. R., McGregor, P. K., & Dabelsteen, T. (2002). Do great tits assess rivals by combining direct experience with information gathered by eavesdropping? Proc Biol Sci, 269(1503), 1925–1929.
Abstract: Animals frequently use signals that travel further than the spacing between individuals. For every intended recipient of a given signal there are likely to be many other individuals that receive information. Eavesdropping on signalling interactions between other individuals provides a relatively cost-free method of assessing future opponents or mates. Male great tits (Parus major) extract relative information from such interactions between individuals unknown to them. Here, we show that male great tits can take information gathering a stage further and obtain more information about a previously unencountered intruder, by the hitherto unknown capability of combining information gathered by eavesdropping with that derived from their own direct interaction with an individual. Prior experience with an intruder (A) was achieved by subjecting a focal male to different levels of intrusion simulated using interactive playback. This intruder (A) then took part in a simulated interaction with an unknown male (B) outside the territorial boundary of the focal males. In response to subsequent intrusion by the second male (B), focal males showed low song output in response to males that had lost to a male that the subject was able to beat. Males of known high quality, or those about which information was ambiguous, elicited a high level of song output by focal males. We discuss the implications of this finding for the evolution of communication and social behaviour.
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Goto, K., Lea, S. E. G., & Dittrich, W. H. (2002). Discrimination of intentional and random motion paths by pigeons. Anim. Cogn., 5(3), 119–127.
Abstract: Twelve pigeons ( Columba livia) were trained on a go/no-go schedule to discriminate between two kinds of movement patterns of dots, which to human observers appear to be “intentional” and “non-intentional” movements. In experiment 1, the intentional motion stimulus contained one dot (a “wolf”) that moved systematically towards another dot as though stalking it, and three distractors (“sheep”). The non-intentional motion stimulus consisted of four distractors but no stalker. Birds showed some improvement of discrimination as the sessions progressed, but high levels of discrimination were not reached. In experiment 2, the same birds were tested with different stimuli. The same parameters were used but the number of intentionally moving dots in the intentional motion stimulus was altered, so that three wolves stalked one sheep. Despite the enhanced difference of movement patterns, the birds did not show any further improvement in discrimination. However, birds for which the non-intentional stimulus was associated with reward showed a decline in discrimination. These results indicated that pigeons can discriminate between stimuli that do and do not contain an element that human observer see as moving intentionally. However, as no feature-positive effect was found in experiment 1, it is assumed that pigeons did not perceive or discriminate these stimuli on the basis that the intentional stimuli contained a feature that the non-intentional stimuli lacked, though the convergence seen in experiment 2 may have been an effective feature for the pigeons. Pigeons seem to be able to recognise some form of multiple simultaneously goal-directed motions, compared to random motions, as a distinctive feature, but do not seem to use simple “intentional” motion paths of two geometrical figures, embedded in random motions, as a feature whose presence or absence differentiates motion displays.
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Hauber, M. E., Pearson, H. E., Reh, A., & Merges, A. (2002). Discrimination between host songs by brood parasitic brown-headed cowbirds ( Molothrus ater). Anim. Cogn., 5(3), 129–137.
Abstract: Songbirds can learn both to produce and to discriminate between different classes of acoustic stimuli. Varying levels of auditory discrimination may improve the fitness of individuals in certain ecological and social contexts and, thus, selection is expected to mold the cognitive abilities of different species according to the potential benefits of acoustic processing. Although fine-scale auditory discrimination of conspecific songs and calls has been frequently reported for brood parasitic brown-headed cowbirds ( Molothrus ater), it remains unclear why and how they perceive differently the songs of their many host species. Using habituation-dishabituation paradigms and measuring behavioral and physiological (heart-rate) responses, we found that captive female cowbirds consistently discriminated between songs of two host species, the song sparrow ( Melospiza melodia) and the red-winged blackbird ( Agelaius phoeniceus). Playback experiments with stimuli composed of con-specific followed by heterospecific vocalizations in the field also demonstrated discrimination between these heterospecific songs even though cowbirds were not attracted to playbacks of either host species' songs alone. Our results do not directly support a nest-searching function of heterospecific song discrimination by cowbirds and are most consistent with a function of the parasites' avoidance of attacks by their aggressive hosts. These data demonstrate discrimination between heterospecific vocalizations by brown-headed cowbirds and add a novel dimension to the already expansive auditory perceptual abilities of brood parasitic species and other songbirds.
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Tebbich, S., Bshary, R., & Grutter, A. S. (2002). Cleaner fish Labroides dimidiatus recognise familiar clients. Anim. Cogn., 5(3), 139–145.
Abstract: Individual recognition has been attributed a crucial role in the evolution of complex social systems such as helping behaviour and cooperation. A classical example for interspecific cooperation is the mutualism between the cleaner fish Labroides dimidiatus and its client reef fish species. For stable cooperation to evolve, it is generally assumed that partners interact repeatedly and remember each other's past behaviour. Repeated interactions may be achieved by site fidelity or individual recognition. However, as some cleaner fish have more than 2,300 interactions per day with various individuals per species and various species of clients, basic assumptions of cooperation theory might be violated in this mutualism. We tested the cleaner L. dimidiatus and its herbivorous client, the surgeon fish Ctenochaetus striatus, for their ability to distinguish between a familiar and an unfamiliar partner in a choice experiment. Under natural conditions, cleaners and clients have to build up their relationship, which is probably costly for both. We therefore predicted that both clients and cleaners should prefer the familiar partner in our choice experiment. We found that cleaners spent significantly more time near the familiar than the unfamiliar clients in the first 2 minutes of the experiment. This indicates the ability for individual recognition in cleaners. In contrast, the client C. striatus showed no significant preference. This could be due to a sampling artefact, possibly due to a lack of sufficient motivation. Alternatively, clients may not need to recognise their cleaners but instead remember the defined territories of L. dimidiatus to achieve repeated interactions with the same individual.
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Jackson, R. R., Pollard, S. D., & Cerveira, A. M. (2002). Opportunistic use of cognitive smokescreens by araneophagic jumping spiders. Anim. Cogn., 5(3), 147–157.
Abstract: Little is known about how a prey species' cognitive limitations might shape a predator's prey-capture strategy. A specific hypothesis is investigated: predators take advantage of times when the prey's attention is focussed on its own prey. Portia fimbriata, an araneophagic jumping spider (Salticidae) from Queensland, is shown in a series of 11 experiments to exploit opportunistically a situation in which a web-building spider on which it preys, Zosis genicularis (Uloboridae), is preoccupied with wrapping up its own prey. Experimental evidence supports three conclusions: (1). while relying on optical cues alone, P. fimbriata perceives when Z. genicularis is wrapping up prey; (2). when busy wrapping up prey, the responsiveness of Z. genicularis to cues from potential predators is diminished; and (3). P. fimbriata moves primarily during intervals when Z. genicularis is busy wrapping up prey. P. fimbriata's strategy is effective partly because the wrapping behaviour of Z. genicularis masks the web signals generated by the advancing P. fimbriata's footsteps and also because, while wrapping, Z. genicularis' attention is diverted away from predator-revealing cues.
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Drapier, M., Chauvin, C., & Thierry, B. (2002). Tonkean macaques ( Macaca tonkeana) find food sources from cues conveyed by group-mates. Anim. Cogn., 5(3), 159–165.
Abstract: It is possible that non-specialised cues transmitted by conspecifics guide animals' food search provided they have the cognitive abilities needed to read these cues. Macaques often check the mouth of their group-mates by olfactory and/or visual inspection. We investigated whether Tonkean macaques ( Macaca tonkeana) can find the location of distant food on the basis of cues conveyed by group-mates. The subjects of the study were two 6-year-old males, who belonged to a social group of Tonkean macaques raised in semi-free-ranging conditions. In a first experiment, we tested whether the subject can choose between two sites after having sniffed a partner who has just eaten food corresponding to one of the sites. We found that both subjects were able to choose the matching site significantly above the chance level. This demonstrated that Tonkean macaques are capable of delayed olfactory matching. They could associate a food location with an odour conveyed by a partner. In a second experiment, the same subjects were allowed to see their partner through a Plexiglas window. Both subjects were still able to choose the matching site, demonstrating they could rely on visual cues alone. Passive recruitment of partners appears possible in macaques. They can improve their foraging performances by finding the location of environmental resources from olfactory or visual cues conveyed by group-mates.
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Funk, M. S. (2002). Problem solving skills in young yellow-crowned parakeets (Cyanoramphus auriceps). Anim. Cogn., 5(3), 167–176.
Abstract: Despite the long divergent evolutionary history of birds and mammals, early avian and primate cognitive development have many convergent features. Some of these features were investigated with a series of tasks designed to assess human infant development. The tasks were presented to young parakeets to assess their means-end problem solving abilities. Examples of these early skills are: attaining and playing with objects, retrieving rewards through use of a stick or rake, or by pulling in rewards on supports or on the ends of strings. Twelve such tasks were presented to 11 young yellow-crowned parakeets ( Cyanoramphus auriceps) to investigate their natural abilities; there was no attempt to train them to do those tasks that they did not spontaneously perform. Six of the birds were parent-raised and five were hand-raised. The birds completed 9 of the 12 tasks, demonstrating all the Piagetian sensorimotor circular reactions, but they failed to hand-watch (“claw-watch”), to stack objects, or to fill a container. Their ordinality on the tasks differed from that of human infants in that locomotion to obtain objects occurred earlier in the avian sequence of development and the mid-level tasks were performed by the two groups of avian subjects in a mixed order perhaps indicating that these abilities may not emerge in any particular order for these birds as they supposedly do for human infants. The hand-raised group needed fewer sessions to complete these means-end tasks.
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Pepperberg, I. M. (2002). The value of the Piagetian framework for comparative cognitive studies. Anim. Cogn., 5(3), 177–182.
Abstract: Although the Piagetian framework has been used by numerous researchers to compare cognitive abilities of diverse species, the system is often criticized as implemented. I examine the various criticisms, suggest ways in which the system can be improved, and argue for the need for descriptive systems such as the Piagetian framework to complement programs that look for cellular and molecular bases or mathematical models to explain behavior.
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