Song amplitude and body size in birds

Abstract

Bird song is a sexually selected multidimensional signal. A fundamental question regarding the evolution of sexually selected signals is what information they convey and how their honesty is maintained. Song amplitude is a performance-related signal trait that varies considerably between individuals, but this signal dimension has been neglected in past studies. I found that median song amplitude in male nightingales (Luscinia megarhynchos) and zebra finches (Taeniopygia guttata) did not vary significantly with body size or residual body mass. In contrast, I found a significant negative correlation between body size (and also residual mass) and the maximum song amplitude during interactive singing in nightingales. However, the function of these more subtle differences in song amplitude remains to be investigated. By and large, the results of this study suggest that mean song amplitude is unlikely to indicate a bird's body size or current condition (measured as residual mass).

Maximum frequency of songs reflects body size among male dusky warblers Phylloscopus fuscatus (Passeriformes: Phylloscopidae)

“…However, in other studies, many song characteristics failed to predict the body size of songbirds (Brumm 2009;Geberzahn et al 2009;Miyashita et al 2016). In these studies, song bandwidths, song rate, average frequency, song amplitude and repertoire size of the total song showed no relationship to body size.…”

“…We measured tarsus length (± 0.1 mm) 3 times at each capture, and used the average length as an indicator of body size. We used tarsus length as our measure of body size for the following three reasons: (1) it is observed to predict male quality and female choice in some birds (Kempenaers et al 1992;Møller & Ninni 1998;Hall et al 2013); (2) it has an observed relationship with call frequency (Price et al 2006;Brumm 2009;Geberzahn et al 2009;Linhart & Fuchs 2015); and (3) it is constant in adults.…”

“…It is well known that advertising songs can indicate body size (Hall et al 2013;Price & Crawford 2013). In many studies, all song characteristics reveal signaler quality through traits such as repertoire size (Soma & Garamszegi 2011;Hesler et al 2012;Kagawa & Soma 2013), song timing (Poesel et al 2006), song amplitude (Brumm 2009;Schuchmann & Siemers 2010), song frequency, song bandwidth or song rate (Potvin 2013;Linhart & Fuchs 2015;Mason & Burns 2015).…”

Inter- and intra-season stability of vocal individual signatures in a social seabird, the crested auklet

“…We can suppose that crested auklets do not tune their individual vocal characteristics in response to such social environmental changes, but our data do not prove the absolute absence of vocal plasticity in adult crested auklets. Further observations are needed to test the effect of other factors such as population density or challenging by a rival that could cause call modifications in animal species both with and without vocal learning (e.g., Howard and Young 1998;Penteriani 2003;Brumm 2009) on acoustic variables of crested auklets calls. Appendix A…”

Variability in Echolocation Call Intensity in a Community of Horseshoe Bats: A Role for Resource Partitioning or Communication?

“…In the American bison, Bison bison , a negative relationship between vocal amplitude and male quality has been found [43]. A negative correlation between body size and maximum song amplitude during interactive singing was also found for nightingales, while there was no correlation for two other songbird species [44].…”