DOI: 10.5061/dryad.ps58g58
title: Data from: Temporal variation in the vocal behaviour of southern right whales in the Auckland Islands, New Zealand

description: Autonomous recorders are frequently utilised for examining vocal behaviour
 of animals, and are particularly effective in remote habitats. Southern
 right whales are known to have an extensive acoustic repertoire. A
 recorder was moored at the isolated sub-Antarctic Auckland Islands for a
 year to examine whether the acoustic behaviour of southern right whales
 differed seasonally and throughout the day at their main calving ground in
 New Zealand. Recordings were made in each month except June, and
 vocalisations were audible in all months with recordings except January. A
 total of 35,487 calls were detected, of which upcalls were the most common
 (11,623). Call rate peaked in August (288±5.9 [SE] calls/hour) and July
 (194±8.3). Vocal behaviour varied diurnally with highest call rates
 detected at dusk and night, consistent with the concept that upcalls
 function primarily as contact calls. Zero-inflated model results confirmed
 that seasonal variation was the most important factor for explaining
 differences in vocal behaviour. An automated detector designed to expedite
 the analysis process for North Atlantic right whales correctly identified
 80% of upcalls, although false detections were frequent, particularly when
 call rates were low. This study is the first to attempt year-round
 monitoring of southern right whale presence in New Zealand.
description: Summary of the analysis
 of the southern right whale vocalisation dataThis spreadsheet
 contains data on the presence of right whale vocalisations for all of the
 recordings from the DSG recorder. Subsequent tabs in the spreadsheet
 contain the analysis of calls by season, month, per day, diel period and
 hour and call typeDSGAnalysisSummary.xlsxSummary of the detector performance dataThis spreadsheet contains data on the performance of the automated detector (the eXtensible BioAcoustic Tool (XBAT) written in MATLAB) which was developed for upcall vocalisations produced by North Atlantic right whales. Manual and automated detections were compared to test the effectiveness and sensitivity of the algorithm for detecting SRW upcalls. We randomly selected 10% of the total number of recordings for verification analysis and annotated the detection events as either true or false based on the manual classification. Two measures of detector performance were applied: Positive Predictive Value (PPV) which represents the percentage of the upcalls logged by the detector that were judged by the human analyst to have been correctly assigned, and True Positive Rate (TPR) which represents the percentage of upcalls detected by the analyst also logged by the detector.Detector performance.xlsxR script for Zero Inflated Model and Likelihood RatioA Zero Inflated Model with a negative binomial distribution was used to evaluate whether particular seasons and/or diel periods were important for explaining differences in right whale call presence and call rate. This script runs the ZIM and conducts a log-likelihood ratio test to determine whether a poisson or negative binomial distribution best fitted the count data.ZIM and likelihood ratio R script.txtR script for jittering the upcall versus detector figureThe number of automatically detected upcalls per recording vs the number of upcalls detected by the analyst has been displayed in a figure. Points required jittering by 0.6 to offset and reveal overlapping points.Jitter upcall v detector R script.txt