Physically Challenging Song Traits, Male Quality, and Reproductive Success in House Wrens

Abstract

Physically challenging signals are likely to honestly indicate signaler quality. In trilled bird song two physically challenging parameters are vocal deviation (the speed of sound frequency modulation) and trill consistency (how precisely syllables are repeated). As predicted, in several species, they correlate with male quality, are preferred by females, and/or function in male-male signaling. Species may experience different selective pressures on their songs, however; for instance, there may be opposing selection between song complexity and song performance difficulty, such that in species where song complexity is strongly selected, there may not be strong selection on performance-based traits. I tested whether vocal deviation and trill consistency are signals of male quality in house wrens (Troglodytes aedon), a species with complex song structure. Males’ singing ability did not correlate with male quality, except that older males sang with higher trill consistency, and males with more consistent trills responded more aggressively to playback (although a previous study found no effect of stimulus trill consistency on males’ responses to playback). Males singing more challenging songs did not gain in polygyny, extra-pair paternity, or annual reproductive success. Moreover, none of the standard male quality measures I investigated correlated with mating or reproductive success. I conclude that vocal deviation and trill consistency do not signal male quality in this species.

Are extra‐pair males different from cuckolded males? A case study and a meta‐analytic examination

“…This difference could be explained by varying degrees of age dependency. Given that behavioural traits tend to be flexible, song characteristics in some bird species might be highly diverse, with lower repeatability than for morphological traits (Catchpole & Slater 2008;Cramer 2013;Rendall & Kaluthota 2013; also see Table S1, Supporting information). Males may increase repertoire sizes with age by learning or delayed performance (Garamszegi et al 2007), so song characteristics might be more age dependent than other traits (Laucht & Dale 2012).…”

“…Ornaments are usually condition dependent, making ornaments less age dependent than song characteristics (Gil & Gahr 2002;Laucht & Dale 2012). Moreover, although body size is also age dependent, most body-size measurements are likely to be more consistent across years than song characteristics once an individual reaches adulthood (Davies et al 1988;Cleasby et al 2011;Cramer 2013; also see the repeatability in Table S1, Supporting information).…”

Transcontinental latitudinal variation in song performance and complexity in house wrens (Troglodytes aedon)

“…In such cases, broad summary evaluations of performance and morphology may fail to identify relationships. Indeed, house wrens are a species noted for having extremely large song repertoires [22,24,55], and recent tests of frequency-bandwidth : trill-rate performance trade-offs in songs of northern house wrens (T. aedon aedon) have failed to find clear correlations with standard metrics of male quality or breeding success [56,57].…”

Fighting talk: complex song elicits more aggressive responses in a vocally complex songbird

“…Song complexity may be an honest indicator of various aspects of male quality (Spencer et al . , Cramer ). These factors include genetic diversity (Marshall et al .…”

“…High songbird song complexity can be both energetically costly in terms of field metabolic rate (Garamszegi et al 2006) and sexually selected (Schmidt et al 2013). Song complexity may be an honest indicator of various aspects of male quality (Spencer et al 2003, Cramer 2013. These factors include genetic diversity (Marshall et al 2003), developmental stress levels (Spencer et al 2003, Nowicki & Searcy 2004) and parasite load (Hamilton & Zuk 1982).…”