DOI: 10.5061/dryad.th40d
title: Data from: Repertoire-based individual acoustic monitoring of a migratory passerine bird with complex song as an efficient tool for tracking territorial dynamics and annual return rates

description: In field ecological and behavioural studies, it is often necessary to
 identify specific individuals. In birds, colour rings are frequently used
 to mark individuals; however, rings are often difficult to observe,
 especially in small species and dense habitats. Acoustic-based monitoring
 detecting individuals by their characteristic vocalization is a
 potentially suitable alternative, but this approach is challenging in
 species with complex songs. On the example of the Tree Pipit (Anthus
 trivialis), a small migratory passerine often singing in flight or from
 perches obscured by foliage, we demonstrate that acoustic monitoring based
 on the syllable repertoire can be very efficient tool for individual
 recognition. During a 3-year study, we obtained over 500 recordings from
 males from one study population (a number of them returning after winter).
 Males banded with colour rings were repeatedly recorded throughout the
 seasons, and syllable repertoires were determined from spectrograms for
 each recording. The repertoire of each unambiguously identified male was
 distinct and stable within as well as between seasons; and males with
 similar syllable repertoires differed in syntax. Based on the congruence
 between identification based solely on spectrogram assessment, and that
 based on observation of colour rings, we inferred that reliable
 identification of singing males (including non-ringed ones) was possible
 in the studied population from assessing a repertoire and song syntax of
 &lt;5-min recording (containing 20–30 songs). The acoustic-based data:
 (i) increased the overall estimated number of territorial males at the
 study locality (from 49 ringed to 61), and improved the estimates of the
 period of their presence; (ii) revealed dynamic within-season changes in
 territory occupancy that would otherwise be missed; and (iii) allowed
 identification of returning birds (including non-ringed ones and those
 actively avoiding approaching humans). Our results suggest that some
 commonly used methods may substantially underestimate return rates of
 migratory bird species. Individual acoustic monitoring should be
 applicable on various bird species with complex song and stable
 repertoires, and may be particularly useful for those living in dense
 habitat or sensitive to handling.
description: recording and male
 repertoires, coded songsThe file in MS Excel
 format containing three sheets: 1: male repertoires: each line represent a
 single Tree Pipit males from the studied locality; for each of them, the
 following information is provided: the total number of song recordings
 available, the number of syllables and bi-syllables detected in the
 male's repertoire, and presence/absence of each syllable and
 bi-syllable type. 2: recording repertoires: each line represent a single
 recording of Tree Pipit songs; for each of them, the following information
 is provided: male identity (as in the first sheet), code of the recording,
 year and date of recording, number of songs within a recording,
 availability of observation data on colour rings, the number of syllables
 and bi-syllables detected within the recording, and presence/absence of
 each syllable and bi-syllable type. 3: coded songs: each line represent a
 single Tree Pipit song for which the syllable sequence was noted; for each
 of them, the following information is provided: male identity (as in the
 first and second sheets), code of the recording (as in the second sheet),
 and sequence of syllables within the song. Each syllable is coded by
 letter that may be followed by number; numbers immediately preceding
 letters denote the number of syllable repetitions; bi-syllables are
 enclosed in parentheses; numbers before parentheses denote bi-syllable
 repetitions.Tree Pipit syllable
 catalogue (Brdy)The file contains
 spectrograms of all syllable types differentiated in songs of the studied
 Tree Pipit population. Characteristics by which different syllable types
 differ from each other are highlighted by arrows.Tree Pipit male ID -
 test packageA package containing all
 files necessary to replicate the blind test of assignment of Tree Pipit
 recordings to individual males by inexperienced observers. Participants
 are provided by a file with instructions, a syllable catalogue,
 spectrograms of 30 recordings included in the test, and test recordings in
 a WAV format. (All these materials are provided in a single ZIP file that
 can be distributed to the participants.) Note that the correct solution of
 the test is provided separately.Tree Pipit male ID -
 test solutionThe solution of the
 blind test of assignment of Tree Pipit recordings to individual males by
 inexperienced observers. The grouping of the 30 recordings included in the
 test, and key identification features of the respective males, are
 provided.