Social context and prey composition are associated with calling behaviour in a diving seabird

McInnes, Alistair; Thiebault, Andréa; Cloete, T.J.; Pichegru, Lorien; Aubin, Thierry; McGeorge, Cuan; Pistorius, Pierre A.

doi:10.1111/ibi.12806

Cited by 14 publications

(9 citation statements)

References 52 publications

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“…African Penguins make extensive use of vocal signals for intra-specific vocal communication (Favaro et al 2016, McInnes et al 2020. The vocal repertoire of adult African Penguins is made up of two discrete call types and two display songs (Favaro et al 2014).…”

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confidence: 99%

Passive acoustic monitoring of the endangered African Penguin (Spheniscus demersus) using autonomous recording units and ecoacoustic indices

Favaro

Cresta

Friard

et al. 2021

Ibis

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African Penguins Spheniscus demersus are endangered and declining seabirds which make extensive use of vocal signals for intra-specific vocal communication. Accordingly, passive acoustic monitoring tools could be developed as robust population monitoring methods that cause minimal disturbance to the birds. In this study, we collected soundscape recordings at the Stony Point penguin colony (Betty's Bay, South Africa) during the breeding season in 2019 to document the circadian rhythms of vocal activity of this species and to investigate whether the magnitude of variation of three different ecoacoustic indices correlates with the number of ecstatic and mutual display songs counted in recordings, which might inform on the breeding activity of the colony. Indeed, whereas ecstatic display songs are produced by males during intersexual competition and territorial defence, mutual display songs are given by parents returning to the nest after foraging trips. We found that the vast majority of the display songs (> 80%) occurred between 04:00-08:00 and 17:30-21:30 h. We also found that the Acoustic Entropy Index was a good predictor of the number of penguins' songs within a recording. Overall, our study shows that African Penguins vocalizations have the potential to assist the monitoring of this species while minimizing disturbance.

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confidence: 99%

Passive acoustic monitoring of the endangered African Penguin (Spheniscus demersus) using autonomous recording units and ecoacoustic indices

Favaro

Cresta

Friard

et al. 2021

Ibis

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“…The surrounding environment of equipped animals is also recorded and could help contextualize specific behaviours [52]. The vocalizations of equipped animals allow the study of variations in social interactions and grouping behaviours in different contexts [123,124]. Furthermore, multi-species associations can be recorded.…”

Section: Discussionmentioning

confidence: 99%

Animal-borne acoustic data alone can provide high accuracy classification of activity budgets

et al. 2021

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Background Studies on animal behaviour often involve the quantification of the occurrence and duration of various activities. When direct observations are challenging (e.g., at night, in a burrow, at sea), animal-borne devices can be used to remotely record the movement and behaviour of an animal (e.g., changing body posture and movement, geographical position) and/or its immediate surrounding environment (e.g., wet or dry, pressure, temperature, light). Changes in these recorded variables are related to different activities undertaken by the animal. Here we explored the use of animal-borne acoustic recorders to automatically infer activities in seabirds. Results We deployed acoustic recorders on Cape gannets and analysed sound data from 10 foraging trips. The different activities (flying, floating on water and diving) were associated with clearly distinguishable acoustic features. We developed a method to automatically identify the activities of equipped individuals, exclusively from animal-borne acoustic data. A random subset of four foraging trips was manually labelled and used to train a classification algorithm (k-nearest neighbour model). The algorithm correctly classified activities with a global accuracy of 98.46%. The model was then used to automatically assess the activity budgets on the remaining non-labelled data, as an illustrative example. In addition, we conducted a systematic review of studies that have previously used data from animal-borne devices to automatically classify animal behaviour (n = 61 classifications from 54 articles). The majority of studies (82%) used accelerometers (alone or in combination with other sensors, such as gyroscopes or magnetometers) for classifying activities, and to a lesser extent GPS, acoustic recorders or pressure sensors, all potentially providing a good accuracy of classification (> 90%). Conclusion This article demonstrates that acoustic data alone can be used to reconstruct activity budgets with very good accuracy. In addition to the animal’s activity, acoustic devices record the environment of equipped animals (biophony, geophony, anthropophony) that can be essential to contextualise the behaviour of animals. They hence provide a valuable alternative to the set of tools available to assess animals’ behaviours and activities in the wild.

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“…Reports on leatherback turtle and dugong vocalisations are scarce and provide little or no evidence for individual vocal signatures (leatherback turtles [67,68], dugongs [69]). Convincing evidence for two voices is thus only available for king penguins [41], emperor penguins [44] and African penguins [70]. The STM could, for example, play an important role in keeping the two independently produced sounds separated until the cranial end of the trachea.…”

Section: Discussionmentioning

confidence: 99%

Vocal tract anatomy of king penguins: morphological traits of two-voiced sound production

et al. 2020

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Background: The astonishing variety of sounds that birds can produce has been the subject of many studies aiming to identify the underlying anatomical and physical mechanisms of sound production. An interesting feature of some bird vocalisations is the simultaneous production of two different frequencies. While most work has been focusing on songbirds, much less is known about dual-sound production in non-passerines, although their sound production organ, the syrinx, would technically allow many of them to produce "two voices". Here, we focus on the king penguin, a colonial seabird whose calls consist of two fundamental frequency bands and their respective harmonics. The calls are produced during courtship and for partner and offspring reunions and encode the birds' identity. We dissected, μCT-scanned and analysed the vocal tracts of six adult king penguins from Possession Island, Crozet Archipelago. Results: King penguins possess a bronchial type syrinx that, similarly to the songbird's tracheobronchial syrinx, has two sets of vibratory tissues, and thus two separate sound sources. Left and right medial labium differ consistently in diameter between 0.5 and 3.2%, with no laterality between left and right side. The trachea has a conical shape, increasing in diameter from caudal to cranial by 16%. About 80% of the king penguins' trachea is medially divided by a septum consisting of soft elastic tissue (septum trachealis medialis). Conclusions: The king penguins' vocal tract appears to be mainly adapted to the life in a noisy colony of a species that relies on individual vocal recognition. The extent between the two voices encoding for individuality seems morphologically dictated by the length difference between left and right medial labium. The septum trachealis medialis might support this extent and could therefore be an important anatomical feature that aids in the individual recognition process.

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Social context and prey composition are associated with calling behaviour in a diving seabird

Cited by 14 publications

References 52 publications

Passive acoustic monitoring of the endangered African Penguin (Spheniscus demersus) using autonomous recording units and ecoacoustic indices

Passive acoustic monitoring of the endangered African Penguin (Spheniscus demersus) using autonomous recording units and ecoacoustic indices

Animal-borne acoustic data alone can provide high accuracy classification of activity budgets

Vocal tract anatomy of king penguins: morphological traits of two-voiced sound production

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