DOI: 10.5061/dryad.2rbnzs82p
title: Contributions of environmental conditions and sound characteristics to differences in perceptibility: Recommendations for passive acoustic monitoring

description: Passive acoustic monitoring is increasingly used in ecological research to
 study a wide variety of taxa; however, properly accounting for
 perceptibility, a component of detection probability, has been challenging
 because sound attenuation is influenced by numerous variables in the
 surrounding environment, and the rate of sound attenuation is not
 typically quantified. We used sound playback experiments to investigate
 the effect of several environmental variables, including vegetation type
 and weather, on the perceptibility of a variety of sounds and species. We
 also investigated species-specific variables such as sound frequency,
 syllable rate, and bandwidth. We quantified the amount of bias in
 perceptibility resulting from species sound characteristics and vegetation
 type, and estimated perceptibility and the area surveyed for different
 combinations of species and habitat type. We found that distance was the
 strongest predictor of perceptibility, but that vegetation type
 significantly influenced perceptibility, particularly when comparing open
 versus closed vegetation classes. Sound frequency and bandwidth of species
 were also important predictors of perceptibility. We found that ignoring
 variation in perceptibility due to excess sound attenuation from
 vegetation could bias area surveyed during acoustic surveys by up to 400%
 (mean = 167.4%). We conclude that other than distance, perceptibility is
 influenced most by species-specific vocalization traits and by the habitat
 these vocalizations transmit through. We provide recommendations for
 incorporating these findings into future research to account for varying
 perceptibility and improve the accuracy of bird monitoring and research.
description: # Contributions of environmental conditions and sound characteristics to
 differences in perceptibility: Recommendations for passive acoustic
 monitoring Dataset DOI: [10.5061/dryad.2rbnzs82p](10.5061/dryad.2rbnzs82p)
 ## Description of the data and file structure Experimental data to
 investigate factors that may influence the detection probability of birds
 and other species. We broadcast vocalizations of species commonly found in
 the Canadian boreal forest and re-recorded them at different distances in
 a variety of vegetation types and under different environmental
 conditions. Audio recorders were listened to by observers to determine if
 sounds were identifiable. ### Files and variables #### File: habitat.csv
 **Description:** All detection data used for ORNITH-APP-24-173 #####
 Variables * Species: species or sound that was broadcast * Observer:
 observer ID, to account for observer variability * ID: identification of a
 sound or species that was broadcast by an observer listening to a
 recording of the sound * Distance: distance between the sound broadcast
 and the audio recorder * Comments: notes about that specific broadcast or
 site * Transect: the id of the transect where the broadcast occurred *
 Habitat: vegetation type that was present during the broadcast * Wind:
 wind speed in km/h * Temp: temperature in degrees Celsius * Humidity:
 humidity as a percentage * Detected: was the species or sound correctly
 identified * Duration: duration of the sound or species signal, in seconds
 * Syllables: the number of syllables present in a species or sound
 broadcast * Srate: the rate at which syllables occurred, calculated as the
 number of syllables per second * MinFreq: the lower bound of a sound or
 species vocalization spectrogram in Hz * MaxFreq: the upper bound of a
 sound or species vocalization spectrogram in Hz * Bandwidth: MaxFreq minus
 MinFreq Missing data code: NA ## Code/software This is a .csv file which
 can be viewed in Excel or imported and manipulated in R or other
 analytical software.