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- ItemAnimal culture: how a birdsong went viral(Cell Press, 2020) Logue, David M.; Leca, Jean-BaptisteA new white-throated sparrow song has overtaken most of Canada in less than 20 years. The explanation for this remarkably fast spread may lie in the southern migratory grounds, where populations from across Canada converge each winter.
- ItemDuetting behavior varies with sex, season, and singing role in a tropical oriole (Icterus icterus)(Oxford University Press, 2017) Odom, Karan J.; Logue, David M.; Studds, Colin E.; Monroe, Michelle K.; Campbell, Susanna K.; Omland, Kevin E.Females and males of many animals combine their vocalizations into coordinated acoustic duets. Duets can mediate both cooperation and conflict between partners, and are common in tropical, sedentary species that may use duets for multiple functions year-round. To elucidate the full range of duet functions, we need to study the individual-level behaviors that generate duets throughout the year. We evaluated multiple functions of duetting behavior in female and male Venezuelan troupials (Icterus icterus) during the breeding and nonbreeding seasons, including territory defense, maintaining contact with a mate, and paternity guarding. In both sexes during both seasons, song initiation rates were predicted by conspecific solo and duet rates. However, troupials were more likely to answer their mate to form duets after conspecific duets than after conspecific solos, supporting a territory defense function of duets. Troupials that answered their mate to form duets were also more likely to move toward their mate (than duet initiators and soloists), suggesting that duet participation also functions to maintain contact. During the breeding season, males were particularly likely to fly toward their mate after answering to form a duet. This finding may indicate that males answer to guard paternity, although other predictions of paternity guarding were not supported. Examining individual-level behaviors during both the breeding and nonbreeding season revealed multiple functions of troupial duets. Our results are consistent with social selection acting on females and males to maintain contact and territories year-round, and possibly sexual selection on males for functions tied to the breeding season.
- ItemThe evolution of vocal duets and migration in New World warblers (Parulidae)(Oxford Academic, 2019) Mitchell, Liam R.; Benedict, Lauryn; Cavar, Jakica; Najar, Nadje; Logue, David M.Vocal duets occur when 2 individuals vocalize in temporal coordination. In birds, duet participation functions to cooperatively defend shared resources, localize mates, and in some species, guard the mate. Previous work indicates that duetting tends to co-evolve with a non-migratory lifestyle, probably because the absence of migration facilitates greater cooperation between mates. We examined the evolution of duetting and migration in New World warblers (Parulidae), a group that has been largely ignored by duetting research. Of the 95 species in our analysis, we found evidence of duetting in 19 (20%) species, and evidence of migration in 45 (47.4%) species. Ancestral character reconstruction indicated that the last common ancestor of the New World warblers did not duet. Duetting evolved multiple times in this group, including 2 early origins and several more recent origins. Migration was present in the last common ancestor and was lost several times. Both duetting and migration exhibit phylogenetic signal. A phylogenetically explicit correlation analysis revealed a significant negative relationship between duetting and migration, in keeping with findings from other avian taxa. This study, the first description of the evolution of duetting in a large avian family with a temperate-zone origin, supports the hypothesis that duetting co-evolves with a sedentary natural history in birds.
- ItemQuantifying song categories in Adelaide's Warbler (Setophaga adelaidae)(Springer, 2019) Kaluthota, Chinthaka D.; Medina, Orlando J.; Logue, David M.Many migratory wood-warblers in the genus Setophaga divide their song repertoires into two categories. Category B songs are usually sung before dawn, with immediate variety and short latencies between songs, whereas category A songs are sung exclusively after dawn, with eventual variety and longer latencies between songs. Songs in different categories may also differ with respect to their acoustic structure. We used an unsupervised clustering algorithm to identify song categories in Adelaide’s Warbler (Setophaga adelaidae), a year-round territorial species. We identified two categories of song types, the characteristics of which are similar to song categories in other migratory wood-warblers. Clusters were not well separated, suggesting that song categories may not be discrete. Song structures in the two categories were similar, but category B songs were shorter and had fewer notes than category A songs. On average, dyads of males shared more category B songs than category A songs, and were more likely to use category B songs when song type matching other males. The most important song delivery variable for separating clusters was residual average run length (residual values control for covariation with time of day), followed by percent of songs delivered before dawn, residual latency, and percent of songs used as song-type matches. We recommend a scheme based on the first three variables to classify novel song types.
- ItemWithin-day improvement in a behavioural display: wild birds 'warm up'(Elsevier, 2017) Schraft, Hannes A.; Medina, Orlando J.; McClure, Jesse; Pereira, Daniel A.; Logue, David M.Motor performance describes the vigour or skill required to perform a particular display. It is a behaviourally salient variable in birdsong and other animal displays, but little is known about within-individual variation in performance over short timescales. The metric ‘frequency excursion’ (FEX) quantifies birdsong performance as cumulative frequency modulation per unit time. We measured FEX in a large sample of recordings from free-living male Adelaide's warblers, Setophaga adelaidae. Our objectives were to quantify natural variation in performance and test the hypotheses that performance (1) improves as a function of recent practise, (2) decreases over consecutive repetitions of a single song type, (3) improves with rest between songs, (4) varies by singing mode and (5) changes during vocal interactions with neighbours. We found significant variation in performance among individuals and song types. Consecutive repetition of a song type, rest between songs, singing mode and vocal interaction did not strongly affect performance. Performance consistently increased with song order, however, indicating that males warm up during morning singing. This is the first demonstration of such an effect in a sexual display. The warm-up effect may explain the prevalence of intense dawn singing in birds (dawn chorus), if rivals engage in an arms race to warm up.
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