@article {53029, title = {Description and classification of Indian Ocean humpback dolphin ( Sousa plumbea ) whistles recorded off the Sindhudurg coast of Maharashtra, India}, journal = {Marine Mammal Science}, volume = {34}, year = {2018}, month = {Jan-07-2018}, pages = {755 - 776}, abstract = {

The Indian Ocean humpback dolphin (Sousa plumbea), a common cetacean species in India, has a diverse vocal repertoire, which to date has not been described in detail. This study focused on analyzing their whistle vocalizations. Humpback dolphins were recorded off the Sindhudurg coast of Maharashtra, India, and 2,260 whistles were analyzed for their acoustic characteristics. Whistles spanned a wide frequency range between 2.3 kHz and 33.0 kHz, with durations ranging from 0.01 s to 1.60 s. Whistles were categorized into seven contour classes based on their qualitative prop- erties. A classification and regression tree (CART) analysis was used to quantify vari- ability between the seven contour classes using the measured acoustic features. Based on the CART analysis, frequency gradient, minimum slope, maximum slope, begin- ning and ending slope accounted for most variability between whistle types. CART resulted in an overall classification accuracy of 89.5\%. This study provides a detailed description of acoustic features and qualitative properties of humpback dolphin whis- tles from the northwestern coast of India. Further comparisons of acoustic data from Sousa populations along the Indian coast are necessary to determine possible geo- graphic variations in whistle characteristics and whether the variations are driven by environmental or genetic factors or a combination of both.

}, keywords = {humpback dolphin, India, passive acoustic monitoring, Sousa plumbea, whistles}, doi = {10.1111/mms.v34.310.1111/mms.12479}, url = {http://doi.wiley.com/10.1111/mms.v34.3}, author = {Bopardikar, Isha and Sutaria, Dipani and Sule, Mihir and Jog, Ketki and Patankar, Vardhan and Klinck, Holger} } @article {52580, title = {Introductory whistle is sufficient for early song recognition by golden-crowned sparrow nestlings}, journal = {Animal Behaviour}, volume = {133}, year = {2017}, month = {Jan-11-2017}, pages = {83 - 88}, abstract = {

Many songbird species have a predisposition to learn conspecific songs, suggesting song learning may be guided by an innate auditory template. Evidence for such a template includes preferential response to conspecific song in early life, even before song learning begins. A prime example of an innate cue for selective song learning is the introductory whistle of white-crowned sparrows, Zonotrichia leucophrys. The songs of its sister species, the golden-crowned sparrow, Zonotrichia atricapilla, also contain an introductory whistle, which differs in structure from that of white-crowned sparrows. Here we tested the ability of nestling golden-crowned sparrows in a sympatric population to discriminate between conspecific and heterospecific songs based on introductory whistles alone, prior to the onset of song learning. Golden-crowned sparrow nestlings responded with more chirps to playbacks of conspecific whistles than to heterospecific (white-crowned sparrow) whistles, and they responded similarly to full conspecific songs and conspecific whistles alone. We suggest that the introductory whistle alone is sufficient for song recognition in the golden-crowned sparrow. We discuss similarities and differences in the role of the introductory whistle between these sister taxa, and how this divergent song phrase may share a role in species recognition in both sister species. Identifying the cues underlying song recognition prior to song learning could be key to understanding the evolution of behavioural isolation between closely related songbird species.

}, keywords = {acoustic template, song learning, species recognition, whistles, Zonotrichia}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.09.018}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217303056}, author = {Hudson, Emily J. and Shizuka, Daizaburo} } @article {47322, title = {Acoustic classification of dolphins in the California Current using whistles, echolocation clicks, and burst pulses}, journal = {Marine Mammal Science}, year = {2016}, month = {Jan-12-2016}, abstract = {

Passive acoustic monitoring of dolphins is limited by our ability to classify calls to species. Significant overlap in call characteristics among many species, combined with a wide range of call types and acoustic behavior, makes classification of calls to species challenging. Here, we introduce BANTER, a compound acoustic classification method for dolphins that utilizes information from all call types produced by dolphins rather than a single call type, as has been typical for acoustic classifiers. Output from the passive acoustic monitoring software, PAMGuard, was used to create independent classifiers for whistles, echolocation clicks, and burst pulses, which were then merged into a final, compound classifier for each species. Classifiers for five species found in the California Current ecosystem were trained and tested using 153 single-species acoustic events recorded during a 4.5 mo combined visual and acoustic shipboard cetacean survey off the west coast of the United States. Correct classification scores for individual species ranged from 71\% to 92\%, with an overall correct classification score of 84\% for all five species. The conceptual framework of this approach easily lends itself to other species and study areas as well as to noncetacean taxa.

}, keywords = {acoustics, burst pulses, classification, delphinids, dolphins, echolocation clicks, whistles}, doi = {10.1111/mms.12381}, url = {http://doi.wiley.com/10.1111/mms.12381}, author = {Rankin, Shannon and Archer, Frederick and Keating, Jennifer L. and Oswald, Julie N. and Oswald, Michael and Curtis, Alex and Barlow, Jay} }