On the maintenance of bird song dialects

Abstract

Abstract. Many bird species, especially song birds but also for instance some hummingbirds and parrots, have noted dialects. By this we mean that locally a particular song is sung by the majority of the birds, but that neighbouring patches may feature different song types. Behavioural ecologists have been interested in how such dialects come about and how they are maintained for over 45 years. As a result, a great deal is known about different mechanisms at play, such as dispersal, assortative mating and learning of songs, and there are several competing hypotheses to explain the dialect patterns known in nature. There is, however, surprisingly little theoretical work testing these different hypotheses at present. We analyse the simplest kind of model that takes into account the most important biological mechanisms, and in which one may speak of dialects: a model in which there are but two patches, and two song types. It teaches us that a combination of little dispersal and strong assortative mating ensures dialects are maintained. Assuming a simple, linear frequency-dependent learning rule has little effect on the maintenance of dialects. A nonlinear learning rule, however, has dramatic consequences and greatly facilitates dialect maintenance. Adding fitness benefits for singing particular songs in a given patch also has a great impact. Now rare song types may invade and remain in the population.

Cultural niche construction of repertoire size and learning strategies in songbirds

“…The literature on niche construction in birds has focused primarily on foraging and nest-building behaviors (Tebbich et al 2001;Odling-Smee et al 2003;Jones et al 1996;Harrison and Whitehouse 2011). Previous models have explored various aspects of avian song learning and its evolution: the origin (Aoki 1989) and maintenance (Lachlan and Slater 1999) of vocal learning itself, the preservation of dialects (Planqué et al 2014), the restrictiveness of ''innate learning preferences '' (sensu Marler 1990;modeled in Lachlan and Feldman 2003), and the effect of the song learning program on song divergence and male dispersal (Ellers and Slabbekoorn 2003). Other theoretical work has investigated the influence of song learning on evolutionary processes, including the link between learned song and male quality (Ritchie et al 2008;Lachlan and Nowicki 2012), as well as the effects of song learning on the evolution of brood parasitism (Beltman et al 2003), on speciation after colonizing a new niche (Beltman et al 2004), and on population divergence in allopatric and sympatric contexts (Lachlan and Servedio 2004;Olofsson and Servedio 2008;Olofsson et al 2011;Rowell and Servedio 2012).…”

Reproductive isolation with a learned trait in a structured population

“…Few theoretical studies (Ellers and Slabbekoorn ; Planqué et al. ) have investigated how spatial limitations on learning affect the potential for speciation.…”

Cultural evolution of killer whale calls: background, mechanisms and consequences

“…For example, a correlation between song syllable variation and allele frequency variation was found in two populations of swamp sparrows (Melospiza georgiana; Balaban, 1988). Theoretical study suggests that little dispersal and assortative mating increase the stability of dialects (Planque et al 2014). The benefit of such reproductive isolation may be the selection of a mate that is better adapted to local conditions.…”