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Klenova A.V.,Moscow State University | Zubakin V.A.,RAS Severtsov Institute of Ecology | Zubakina E.V.,Russian Bird Conservation Union
Acta Ethologica | Year: 2012

Vocal plasticity due to changes of social context is well documented in passerine birds. In other bird species, the impact of social environment changes on the whole vocal structure and on individual specific signatures remains largely unexplored. Here, we assessed inter- and intra-season stability of specific features of individual signatures in advertising calls of crested auklet (Aethia cristatella) males and tested the effects of pair mate and territory changes on the stability of the calls. The crested auklet is a highly social seabird of the North Pacific that breeds in dense colonies, and its individuals switch pair mates and territories with probability of 25-54%. During summer 2008-2010, we recorded 464 trumpet calls from 21 individually marked males and determined their pair mates and positions of their displaying places on a breeding colony of Talan Island, Sea of Okhotsk. We found that strong individual specific features of crested auklet trumpet calls stay stable not only during one season but also from year to year. However, we failed to find any effects of pair mate or territory changes on individual signatures of crested auklet trumpet calls. Our results suggest that crested auklets can potentially use their individually specific trumpet calls to form long-term social bonds both between pair mates and between neighbors; however, future experimental studies should test whether this is indeed the case. © 2011 Springer-Verlag and ISPA.

Klenova A.V.,Moscow State University | Zubakin V.A.,RAS Severtsov Institute of Ecology | Zubakina E.V.,Russian Bird Conservation Union
Moscow University Biological Sciences Bulletin | Year: 2011

Crested auklet is a unique representative of the family Alcidae with a complex social behavior nesting in dense colonies with a size of up to one million individuals. Here we study specific individual features in their trumpet calls, loud vocalizations used by auklets as an advertising display. In 2008 and 2009, we recorded 231 calls of 24 individually marked male crested auklets from the Talan Island (Sea of Okhotsk). According to a stepwise discriminant function analysis based on seven variables in the call introduction, the rate of correct call assignment to an individual was 84.8% and that in the case of seven variables of the main part of the call was 82.3%, which considerably exceeds a random classification. Thus, a single introduction or a single main part of the call is sufficient for a reliable individual identification of a calling bird. We assume that such redundancy of information for individual recognition can enhance identification of calls of a large number of auklet conspecifics in dense colonies with a nesting density of several tens of pairs per 1 m2. © 2011 Allerton Press, Inc.

Klenova A.V.,Moscow State University | Zubakin V.A.,RAS Severtsov Institute of Ecology | Zubakina E.V.,Russian Bird Conservation Union
Ethology | Year: 2011

Indicators of individual quality in ornamentation or in vocalizations have been reported for different animal species. However, no studies have jointly investigated ornamentation and vocalizations in one species. The crested auklet (Aethia cristatella, Alcidae) is a small colonial seabird of the North Pacific and is unusual for a bird in using optical, vocal, and olfactory signals. We estimated the potential for coding individual quality in vocalizations and plumage ornamentation and the relationship between vocal and optical traits in crested auklets. During the summer seasons of 2008-2009, we recorded 359 trumpet calls from 28 individually marked males and measured indices of body size, condition, and plumage patterns of 58 male and 48 female crested auklets from a breeding colony on Talan Island, Sea of Okhotsk. We found strong interindividual differences in trumpet call characteristics. Furthermore, we found that the maximum fundamental frequency of the loudest notes of the trumpet call is negatively correlated with body condition, and head crest length is positively correlated with body size. However, we found no relationship between vocal and ornamental traits. The results suggest that advertising calls of crested auklets signal caller individuality and quality, but future experimental studies should test whether or not this is indeed case. © 2011 Blackwell Verlag GmbH.

Zubakin V.A.,RAS Severtsov Institute of Ecology | Volodin I.A.,Moscow State University | Klenova A.V.,Moscow State University | Zubakina E.V.,Russian Bird Conservation Union | And 2 more authors.
Biology Bulletin | Year: 2010

The crested auklet, a highly social planktivorous bird species of the Northern Pacific, is an important component of marine ecosystems. Although visual and acoustic modalities play a major role in the communication of these birds, the available data on the repertoire of their vocal signals and postures are scarce and lack quantitative analysis. This study deals with visual and acoustic displays of crested auklets on their breeding grounds and the occurrence frequencies of certain forms of social behavior in male and female birds. The data were collected on Talan Island (the Sea of Okhotsk) in 1987-1991 and 2008. They show that the rate of contacts between birds is very high and sex-specific: on average, males initiate 1.13 contacts/min, compared to 0.65 contacts/min initiated by females. Directionality of ruff-sniff displays differs depending on the posture of the recipient bird. The duration of the trumpeting display in males depends on their social surroundings. However, the duration of either the trumpeting display or the mutual cackling display during courtship is independent of the behavioral context. Vocalization of crested auklets is characterized by two independent basic frequencies occurring either sequentially or simultaneously. The role of different communicative modalities in the behavior of the crested auklet is discussed. © 2010 Pleiades Publishing, Ltd.

Klenova A.Y.,Moscow State University | Zubakin Y.A.,RAS Severtsov Institute of Ecology | Zubakina E.V.,Russian Bird Conservation Union | Kolesnikova Yu.A.,Moscow State University
Zoologicheskii Zhurnal | Year: 2012

Crested and parakeet auklets (Aethia cristatella and Cyclorhynchus psitaculla) are closely related planktonfeeding auk species that usually have complex social communicative behavior during breeding seasons. They differ to a great extent by the breeding density and development of sexual dimorphism in external features. The indicators of individuality and sex in advertising calls are compared, and the sexual variation in morphometric features of both species is analyzed. The studies were carried out at Talan Island (the northern Sea of Okhotsk) in 2008-2010. A total of 210 crested and 35 parakeet auklets were captured; for each bird, standard morphometric variables were measured, and the genetic determination of sex was determined. A total of 110 advertising calls from 9 males and 4 females of crested auklet and 110 calls from 8 males and 5 females of parakeet auklet were analyzed. Individual vocal signatures were more reliable in crested auklet breeding with higher density than those in parakeet auklet. It is suggested that in species with higher population density, a risk of mistake during individual recognition between neighbors is rather high; therefore, striking individually specific calls are more important for these species than for breeders with lower density. On the contrary, sex vocal signatures were reliable only in parakeet auklet (94.0%, p < 0.001), while the sex features in calls of crested auklet were insignificant (p > 0.05). The sex of crested auklet could be determined on the basis of morphometric parameters with 94.3% accuracy (p < 0.001), while sex of parakeet auklets could not be determined using the same morphometry procedures (p > 0.05). A lack of external sexual dimorphism can lead to the development of more reliable keys for the identification of sex in vocalizations.

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