Individuality, kin similarity and experimental playback of contact calls in cooperatively breeding riflemen

Riflemen/tītipounamu (Acanthisitta chloris) are kin-based cooperatively breeding birds, which appear able to recognise their relatives. Here, we investigate the potential for vocalisations to act as recognition cues in riflemen. We identified an appropriate contact call and recorded it at the nest from 19 adult riflemen. Measurements of call characteristics were individually repeatable. In addition, call similarity was significantly correlated with relatedness among all birds and among males. Thus, in principle, these contact calls contain sufficient information for individual recognition of familiar kin, and some assessment of relatedness between unfamiliar birds. To test whether riflemen responded differently to calls of kin, we broadcast calls of relatives and non-relatives as separate treatments in a playback experiment. Focal birds rarely responded aggressively or affiliatively, and their tendency to do so was unrelated to treatment. We conclude that zip calls are suitable kin recognition cues, but whether they are used as such remains unknown

Description of the acoustical interaction and synchronization between duetters of the Large-footed Finch (Pezopetes capitalis)

Duets are highly coordinated acoustical displays produced by two individuals. Studying the structure of duet songs and its causes is essential to understand the ecological role and evolution of this form of communication. Our goals in this study were to describe the structure of the duet of the Large-footed Finch, the temporal synchronization of each individual, and to test the effect of provoked (playback) duets. We recorded birds at Cerro de la Muerte, Costa Rica and simulated territory intrusions using playback trials. The duet of this species consisted of overlapping notes between both members of a mated pair, which were emitted either randomly or periodically. Temporal synchronization was similar between both individuals in a mated pair. Both partners adjust the silent intervals between notes in response to the duration of its partner’s note. The high frequency of the second part of the duet of this species decreased with time and the second individual, in duetting this part, not only synchronized its notes temporally with the first individual, but also synchronized the high frequency. The high frequency of the first note the second individual sung was a bit lower than the previous note sung by the first individual. Finally, birds responding to provoked duets produced duets with higher frequency and higher rate of notes compared to unprovoked duets. Our results provide information on the temporal and frequency synchronization in duets of an endemic emberizid and provide new information about a less reported vocal behaviour in bird duets, the acoustic frequency coordination.Fondo Alexander F. SkutchUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Quantitative acoustic differentiation of cryptic species illustrated with King and Clapper rails

Reliable species identification is vital for survey and monitoring programs. Recently, the development of digital technology for recording and analyzing vocalizations has assisted in acoustic surveying for cryptic, rare, or elusive species. However, the quantitative tools that exist for species differentiation are still being refined. Using vocalizations recorded in the course of ecological studies of a King Rail (Rallus elegans) and a Clapper Rail (Rallus crepitans) population, we assessed the accuracy and effectiveness of three parametric (logistic regression, discriminant function analysis, quadratic discriminant function analysis) and six nonparametric (support vector machine, CART, Random Forest, k�nearest neighbor, weighted k�nearest neighbor, and neural networks) statistical classification methods for differentiating these species by their kek mating call. We identified 480 kek notes of each species and quantitatively characterized them with five standardized acoustic parameters. Overall, nonparametric classification methods outperformed parametric classification methods for species differentiation (nonparametric tools were between 57% and 81% accurate, parametric tools were between 57% and 60% accurate). Of the nine classification methods, Random Forest was the most accurate and precise, resulting in 81.1% correct classification of kek notes to species. This suggests that the mating calls of these sister species are likely difficult for human observers to tell apart. However, it also implies that appropriate statistical tools may allow reasonable species�level classification accuracy of recorded calls and provide an alternative to species classification where other capture� or genotype�based survey techniques are not possible

Data from: A novel method for using ecoacoustics to monitor post‐translocation behaviour in an endangered passerine

1. Conservation translocations are an important tool in wildlife management, but have traditionally suffered from a low success rate. Increasing understanding of animal behaviour is vital in improving the success of translocations, but few methods exist to efficiently monitor highly mobile and cryptic species post-release. 2. We present a novel approach to using dynamic occupancy modelling in combination with data derived from autonomous acoustic recording units to monitor the post-release behaviour of hihi (Notiomystis cincta), a threatened endemic bird, at a translocation site in New Zealand. The process of analysing large quantities of acoustic data was facilitated by using automated classifiers and manual validation, an approach that was both accurate and efficient. 3. We find that this approach detects behavioural change consistent with the transition from exploration of a new site to territory formation. We identify that hihi territories at the study site were closely linked to watercourses, but were not related to distance from release site. 4. We find that this method is able to effectively monitor post-release dispersal, and could provide a cost-efficient and less invasive alternative to radio-tracking for monitoring of vocal species