@article {58030,
	title = {Individual signatures outweigh social group identity in contact calls of a communally nesting parrot},
	year = {2019},
	abstract = {<p>Despite longstanding interest in the evolutionary origins and maintenance of vocal learning, we know relatively little about how social dynamics influence vocal learning processes in natural populations. The \&ldquo;signaling group membership\&rdquo; hypothesis proposes that socially learned calls evolved and are maintained as signals of group membership. However, in fission\&ndash;fusion societies, individuals can interact in social groups across various social scales. For learned calls to signal group membership over multiple social scales, they must contain information about group membership over each of these scales, a concept termed \&ldquo;hierarchical mapping.\&rdquo; Monk parakeets (Myiopsitta monachus), small parrots native to South America, exhibit vocal mimicry in captivity and fission\&ndash;fusion social dynamics in the wild. We examined patterns of contact call acoustic similarity in Uruguay to test the hierarchical mapping assumption of the signaling group membership hypothesis. We also asked whether geographic variation patterns matched regional dialects or geographic clines that have been documented in other vocal learning species. We used visual inspection, spectrographic cross-correlation and random forests, a machine learning approach, to evaluate contact call similarity. We compared acoustic similarity across social scales and geographic distance using Mantel tests and spatial autocorrelation. We found high similarity within individuals, and low, albeit significant, similarity within groups at the pair, flock and site social scales. Patterns of acoustic similarity over geographic distance did not match mosaic or graded patterns expected in dialectal or clinal variation. Our findings suggest that monk parakeet social interactions rely more heavily upon individual recognition than group membership at higher social scales.</p>
},
	keywords = {contact call, group membership, hierarchical mapping, individual signatures, machine learning, monk parakeet, Myiopsitta monachus, vocal learning},
	doi = {10.1093/beheco/arz202},
	url = {https://academic.oup.com/beheco/advance-article/doi/10.1093/beheco/arz202/5680715},
	author = {Smith-Vidaurre, Grace and Araya-Salas, Marcelo and Wright, Timothy F},
	editor = {Naguib, Marc}
}
@article {53229,
	title = {Effects of metronomic sounds on a self-paced tapping task in budgerigars and humans},
	journal = {Current Zoology},
	year = {2018},
	month = {Nov-10-2018},
	abstract = {<p>The origin of rhythmic synchronisation or entrainment to a musical beat in animals have been widely discussed. Parrots are suitable animals to examine the relationship between the capability of vocal learning and spontaneous rhythmic synchronisation. In this study, budgerigars (Melopsittacus undulatus) learned to tap (peck) two keys alternately at a self-paced rate. Then, the metronomic sounds were played in the background during test sessions while the birds were performing the key pecking task, although they were not required to synchronise tap timing with the metronome. We found modest but significant effects of the metronome rhythms on the tap timing in some subjects. We also tested humans (Homo sapiens) using almost the same method. In contrast to the birds, a number of human subjects synchronised tap timing to the onset of the metronome without verbal or documented instructions. However, we failed to find an effect of the metronome on self-paced tap timing in some human subjects, although they were capable of rhythmic synchronisation. This is the first report describing the effects of metronomic sounds on self-paced tapping in non-human vocal learners. This study introduces a new method that can be used in future research comparing birds that differ in vocal learning capacities, social structure, age, sex, hormonal status, and so on as part of examinations of the evolutionary foundations of beat processing.</p>
},
	keywords = {operant conditioning, parrots, rhythm, synchronisation, vocal learning},
	issn = {1674-5507},
	doi = {10.1093/cz/zoy075},
	url = {https://academic.oup.com/cz/advance-article/doi/10.1093/cz/zoy075/5126939},
	author = {Seki, Yoshimasa and Tomyta, Kenta}
}
