The songs of male pied flycatchers: exploring the legacy of the fathers

Abstract

Singing is a key element of songbirds’ behavioral repertoire, particularly for males, which sing during the breeding season to defend resources against other males and to attract females. Different song traits may convey honest information about males’ qualities or conditions, which may be used by females to select their mates. Traits under strong sexual selection have an important component of additive genetic variation (i.e., the main genetic inheritance from parents), and so relatively high heritability; therefore, it can be expected that song traits also do. Although the act of singing is an innate behavior, and thus, genetically determined, songbirds need to learn their songs and therefore the genetic contribution to song traits may be reduced by the effect of environmental factors. We tested this hypothesis in seven song traits recorded in the long-distance migratory bird, the pied flycatcher (Ficedula hypoleuca). From a 23-year database (1992–2015), we obtained songs for 28 father–son pairs, and for each song trait we applied parent–offspring regressions to estimate heritability. The type of syllables sung are learned from tutors, and here we also determined the cultural contribution of fathers to the song repertoires of their sons, by quantifying the percentage of syllables that sons shared with their fathers, and compared this with what sons shared with other males in the population (e.g., neighbors). The heritabilities of song traits were highly variable (ranging from −0.22 to 0.56), but most of these were around zero and none of them were significant. These results indicate that the seven song traits are most likely determined by environmental factors. Sons shared more syllables with their fathers than with neighbors (21% vs. 3%), suggesting that fathers are important song tutors during the nestling period. We conclude that there is a cultural inheritance from fathers to their sons’ syllable repertoires, but there is no strong evidence for a genetic contribution of fathers to the seven song traits studied.

Like Father Like Son: Cultural and Genetic Contributions to Song Inheritance in an Estrildid Finch

“…Sons resembled their social father in all measures of song structure, with no effect of genetic relatedness in any case, suggesting that these traits are culturally inherited within populations. Note repertoire size was similar in sons and their social fathers, as is the case for many other species (Grant and Grant, 1996;Takahasi and Okanoya, 2010;Soma, 2011;Labra and Lampe, 2018). We also found evidence for cultural inheritance of song complexity, as measured by linearity (Scharff and Nottebohm, 1991), and of higher order note sequencing, as measured by differential entropy.…”

Estimating heritability of song considering within-individual variance in a wild songbird: The collared flycatcher

“…We estimated relatedness among individuals based on Single Nucleotide Polymorphisms (SNPs), as a required input for the statistical assessment of additive genetic variance. Based on previous works (Labra and Lampe, 2018;Mets and Brainard, 2018;Lewis et al, 2021), we predicted that additive genetic variance and heritability will be low as the song traits investigated in this study are plastic and probably have learned elements (Eriksen et al, 2009(Eriksen et al, , 2011. However, we expected higher heritability estimates for morphology-related song traits (e.g., song frequency).…”

“…The species is probably an open-ended learner, similar to its sister species, the pied flycatcher (Ficedula hypoleuca) (Eriksen et al, 2011). Likewise, males may learn song elements from their fathers (Labra and Lampe, 2018), however, this way of learning is probably limited as males rarely sing after pairing (Garamszegi et al, 2004). Additionally, there is some indication that song learning could have heritable elements in this species (Wheatcroft and Qvarnström, 2017).…”

“…Therefore, measuring the heritability of these traits considering withinindividual variation is essential for assessing their evolutionary potential. The few studies-a handful in wild populationson the heritability of song have found low values (Forstmeier et al, 2009;Labra and Lampe, 2018;Mets and Brainard, 2018;Lewis et al, 2021), probably because of the high plasticity of song and because social learning is an essential process in song development (Beecher and Brenowitz, 2005;Trösch et al, 2017;Lewis et al, 2021). The heritability may differ between song traits because song traits that are mostly learned should have lower heritability (although song learning itself can have heritable elements; Wheatcroft and Qvarnström, 2017), while, as morphological traits generally have high heritability (Stirling et al, 2002), traits related to morphology (e.g., song frequency, which is influenced by the morphology of the vocal tract) should have higher heritabilities (Forstmeier et al, 2009).…”

A Call to Expand Avian Vocal Development Research

“…Similarly, white-crowned sparrows begin their subsong after leaving the natal territory, but most other birds begin their subsong when they are still dependent fledglings (Nelson et al, 1995;Whaling et al, 1995;Park et al, 2005). Both zebra finches and whitecrowned sparrows crystallize their song before their first breeding season and are unable to add or improvise vocalizations in adulthood, unlike open-ended vocal learners (see Araya-Salas and Wright, 2013;Labra and Lampe, 2018). Furthermore, even from the limited data available, it is clear that even among closely related species (such as among white-crowned sparrow subspecies and between song sparrows and swamp sparrows, see Figure 2), there are differences in vocal development stages, such as length and onset, which may be related to life history strategy, such as migratory status, age of sexual maturity, mating strategy, and lifespan (see Supplementary Data 1).…”