@article{d996f6bbe083409dba080cf60ef87b5e,
title = "Group chorusing as an intragroup signal in the greater ani, a communally breeding bird",
abstract = "Group living often requires maintaining dynamic and varied relationships with fellow group members, while simultaneously monitoring and interacting with external competitors. Group members in many social species vocalize together to produce duets or choruses—coordinated, often conspicuous vocal displays—that may play a role in these interactions. Compared with male–female duets, however, relatively little research exists on the function and adaptive significance of group choruses, which involve three or more individuals. Here we investigate chorusing behavior in the greater ani (Crotophaga major), a communally breeding cuckoo that nests in stable social groups of four to eight unrelated individuals. Groups may remain together for several years on the same nesting territory, and groups occasionally destroy each other's clutches in conflicts over high-quality territories. We asked whether the raucous, highly stereotyped choruses performed by ani groups are primarily used for intra- or intergroup communication, and whether they contain information about the identity of the social group and the number of birds vocalizing. Behavioral observations and acoustic recordings from three breeding seasons revealed that choruses typically occurred during social interactions within the group (78% of choruses) or in response to a predator or extra-group individual (17%) and only rarely in intergroup interactions (4%). Consistent with this finding, choruses did not reliably reflect the number of birds vocalizing, and we found only limited evidence for group-specific acoustic signatures (driven by a single group whose choruses were highly distinct). These results suggest that group choruses play an important role in intra-group signaling, potentially in contexts such as group formation, reinforcement of social bonds within the group, and/or collective decision-making, and they motivate new research questions about the role of collective signaling in social evolution.",
keywords = "collective signaling, duetting, greater ani, group formation, identity signature, size signature",
author = "Amanda Savagian and Christina Riehl",
note = "Funding Information: We are very grateful to Danielle Almstead, Luke Carabbia, Christa Morris, Zach Smart, Maria Smith, Meghan Strong, and Oliver Whang for assistance in collecting chorus recordings. The staff at the Smithsonian Tropical Research Institute, especially Oris Acevedo and Melissa Cano, provided invaluable logistical support in the field. We thank Mirjam Kn{\"o}rnschild and Sabine Wieluch for sharing their Matlab script modifications to the Speech Processing Toolbox and Bernard Lohr for guidance on visualizing spectrograms. Fieldwork was funded by grants to A.G.S from the American Philosophical Society, the Animal Behavior Society, Sigma Xi, the Department of Ecology and Evolutionary Biology at Princeton University, the Princeton Institute for International and Regional Studies, and the Princeton Program in Latin American Studies; and by grants to C.R. from the National Science Foundation (IOS-1755279 and IOS-184543). A.G.S was additionally supported by a National Science Foundation Graduate Research Fellowship (DGE-1656466) and a writing fellowship from the Princeton Institute for International and Regional Studies. Funding Information: We are very grateful to Danielle Almstead, Luke Carabbia, Christa Morris, Zach Smart, Maria Smith, Meghan Strong, and Oliver Whang for assistance in collecting chorus recordings. The staff at the Smithsonian Tropical Research Institute, especially Oris Acevedo and Melissa Cano, provided invaluable logistical support in the field. We thank Mirjam Kn{\"o}rnschild and Sabine Wieluch for sharing their Matlab script modifications to the Speech Processing Toolbox and Bernard Lohr for guidance on visualizing spectrograms. Fieldwork was funded by grants to A.G.S from the American Philosophical Society, the Animal Behavior Society, Sigma Xi, the Department of Ecology and Evolutionary Biology at Princeton University, the Princeton Institute for International and Regional Studies, and the Princeton Program in Latin American Studies; and by grants to C.R. from the National Science Foundation (IOS‐1755279 and IOS‐184543). A.G.S was additionally supported by a National Science Foundation Graduate Research Fellowship (DGE‐1656466) and a writing fellowship from the Princeton Institute for International and Regional Studies. Publisher Copyright: {\textcopyright} 2022 Wiley-VCH GmbH.",
year = "2023",
month = feb,
doi = "10.1111/eth.13345",
language = "English (US)",
volume = "129",
pages = "63--73",
journal = "Ethology",
issn = "0179-1613",
publisher = "Wiley-Blackwell",
number = "2",
}