Abstract: In animal communication natural selection favors callers who vocalize to affect the behavior of listeners and listeners who acquire information from vocalizations, using this information to represent their environment. The acquisition of information in the wild is similar to the learning that occurs in laboratory conditioning experiments. It also has some parallels with language. The dichotomous view that animal signals must be either referential or emotional is false, because they can easily be both: The mechanisms that cause a signaler to vocalize do not limit a listener's ability to extract information from the call. The inability of most animals to recognize the mental states of others distinguishes animal communication most clearly from human language. Whereas signalers may vocalize to change a listener's behavior, they do not call to inform others. Listeners acquire information from signalers who do not, in the human sense, intend to provide it.

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.

Abstract: Female zebra finches show a preference for male zebra finches over heterospecific males based solely on the auditory cues of males, such as songs. The present study was designed to investigate whether females show a similar preference for male zebra finches based solely on visual cues. Using a Y-maze apparatus, social preference of female zebra finches was studied between male zebra finches and male Bengalese finches in three experiments. In experiment 1, where female zebra finches could see and hear live male zebra finches and male Bengalese finches, the females preferred to associate with the male zebra finches. In experiment 2, using a sound-attenuated experimental apparatus, subjects could see, but not hear, male zebra finches and male Bengalese finches. The subjects did not show a significant preference for associating with zebra finches. In experiment 3, as in experiment 2, females could see live male zebra finches and male Bengalese finches in the sound-attenuated chambers. However, in experiment 3, the subjects also heard prerecorded auditory cues (i.e., songs and calls) of male zebra finches, which were presented simultaneously in both arms of the maze. Although the females could not use the auditory cues to identify the location of the male zebra finches, they preferred to associate with the male zebra finches rather than the male Bengalese finches. These results suggest that visual cues alone were effective in initiating choice behaviors by females and that auditory cues facilitate such visually based choice behaviors.

Abstract: Having a radio playing during the daytime at some equine establishments is common practice, but few studies have investigated whether particular music genres could be enriching for stabled horses or whether they may be perceived as aversive. This study aimed to establish whether behavioural responses differed when exposed to musical genres (Classical, Country, Jazz and Rock) and when compared to a control (no music). Eight Thoroughbred geldings (age range 8-10 years, average 8.9 years) were exposed to four musical environments and the control environment (no music) and observed in their usual stable, using instantaneous focal sampling every thirty seconds according to a pre-determined ethogram. Each horse was exposed to each genre for an hour in total, at a time when there was no human traffic or interference on the yard. All horses had been stabled for three hours before the study began. The association between genres and behavioural frequencies recorded for each environment was tested using Fisher’s Exact test of association (P<0.01), IBM SPSS21. No statistically significant associations (P=1.0) were recorded between alert or relax behaviours in Country, Classical, and Control environments. Significant associations (P<0.001) between frequency of alert behaviours and Jazz and Rock environments were noted. The latter genres appeared the most aversive which may be due to fast tempo and minor key, especially in the Jazz piece used. Country and Classical genres were slow tempo with a major key and appeared to result in more restful behaviours than Jazz or Rock. Further research is needed to; assess whether music could be used as an enriching tool, and investigate equine emotional capabilities to understand the emotional effects of music. Future studies could also consider how music impacts upon the behaviour of the human handler and whether this influences equine behaviour.