DOI: 10.5061/dryad.34jb6
title: Data from: Three decades of cultural evolution in Savannah sparrow songs

description: Cultural evolution can result in changes in the prevalence not only of
 different learned song types within bird populations but also of different
 segments within the song. Between 1980 and 2011, we examined changes
 within different segments of the single songs of male Savannah sparrows,
 Passerculus sandwichiensis, in an island population. Introductory notes
 did not change. The buzz segment showed similar stability; although a rare
 low-frequency variant appeared and then disappeared, the buzz segments
 from 1980 and 2011 were essentially identical. The middle segment, made up
 of discrete notes assembled into several types, was variable. However, the
 form of the middle segment did not affect fitness and may serve to denote
 individual identity. The terminal trill decreased steadily in frequency
 and duration over three decades. Longer trills were associated with lower
 reproductive success, suggesting that trill duration was under sexual
 selection. The notes sung between introductory notes were also associated
 with reproductive success. A high cluster sung in 1980–1982 disappeared
 altogether by 2011, and was gradually replaced by click trains, which were
 associated with greater reproductive success. During the final decade of
 the study, more clicks were added to click trains. Longer click trains,
 which may require vocal virtuosity and so indicate male quality, were also
 associated with greater reproductive success. Both trill duration and the
 number of clicks increased in variance during the three-decade span of the
 study. We suggest that such increases in variance might be a signature of
 directional cultural selection. Within the Savannah sparrow’s relatively
 short and simple learned song, cultural evolution appears to be mediated
 by different mechanisms for different song segments, perhaps because the
 segments convey different information.
description: SASP-CultEvolSongsSonograms of the songs included in this repository. Examples of five different song types (defined by the "middle" section of the song) are shown for six recording periods spanning the years from 1980 to 2011.1980-2ChExample of a 1980 song with 2 "Ch" notes (.wav format, uncompressed, 16 bit, 44 kHz).1982-StutterExample of a 1982 stutter song (.wav format, uncompressed, 16 bit, 44 kHz).1982-Dash+ChExample of a 1982 Dash + Ch song (.wav format, 16 bit, 44 kHz)1982-DashCh.wav1980-DashShortNotesExample of a 1982 Dash + short note song (.wav format, 16 bit, 44 kHz)1980-SingleNoteExample of a 1980 single Ch song (.wav format, 16 bit, 44 kHz)1989-2ChExample of a 1989 two "Ch" note song (.wav format, 16 bit, 44 kHz)1989-StutterExample of a 1989 stutter song (.wav format, 16 bit, 44 kHz)1988-DashChExample of a 1988 Dash + Ch song (.wav format, 16 bit, 44 kHz)1988-DashShortNotesExample of a 1988 Dash + short note song (.wav format, 16 bit, 44 kHz)1989-SingleNoteExample of a 1989 single note (dash) song (.wav format, 16 bit, 44 kHz)1993-2ChExample of a 1993 two Ch note song (.wav format, 16 bit, 44 kHz)1993-StutterExample of a 1993 stutter song (.wav format, 16 bit, 44 kHz)1993-DashChExample of a 1993 Dash + Ch song (.wav format, 16 bit, 44 kHz)1993-DashShortNotesExample of a 1993 Dash + short notes song (.wav format, 16 bit, 44 kHz)1993-SingleNoteExample of a 1993 single note (dash) song (.wav format, 16 bit, 44 kHz)1998-2ChExample of a 1998 two Ch note song (.wav format, 16 bit, 44 kHz)1998-StutterExample of a 1998 stutter song (.wav format, 16 bit, 44 kHz)1998-DashChExample of a 1998 Dash + Ch song (.wav format, 16 bit, 44 kHz)1998-SingleNoteExample of a 1998 single note (dash) song (.wav format, 16 bit, 44 kHz)1993-SingleNote.wav2004-2ChExample of a 2004 two Ch note song (.wav format, 16 bit, 44 kHz)2004-StutterExample of a 2004 stutter song (.wav format, 16 bit, 44 kHz)2004-DashChExample of a 2004 Dash + Ch song (.wav format, 16 bit, 44 kHz)2004-DashShortNoteExample of a 2004 Dash + short note song (.wav format, 16 bit, 44 kHz)2004-SingleNoteExample of a 2004 single note (dash) song (.wav format, 16 bit, 44 kHz)2011-2ChExample of a 2011 two Ch song (.wav format, 16 bit, 44 kHz)2011-StutterExample of a 2011 stutter song (.wav format, 16 bit, 44 kHz)2011-DashChExample of a 2011 Dash + Ch song (.wav format, 16 bit, 44 kHz)