Distinguishing females of capuchino seedeaters: call repertoires provide evidence for species-level diagnosis

Márcio Repenning,Carla Suertegaray Fontana

doi:10.1007/bf03544451

Márcio Repenning, Carla Suertegaray Fontana

Open Access

https://doi.org/10.1007/bf03544451

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Abstract

Reliable identification of cryptic Neotropical capuchino seedeater females remains as a recurrent and non-trivial issue in field ornithology. Even in the hand, capuchino females cannot be accurately diagnosed to the species level based solely on visual plumage examination, which may present a problem for future research on this group. During 10 years of field research on this group, we observed subtle vocal differences. We studied females of two parapatric species that may breed in syntopic upland grassland areas in southern Brazil: Tawny-bellied Seedeater Sporophila hypoxantha and Black-bellied Seedeater Sporophila melanogaster. Our main aim was to measure dissimilarities between inter-specific and intersexual repertory calls. We found unequivocal inter-specific divergences in call type repertoires revealed by cluster analysis, and no intersexual differences in the co-specific repertoire calls. These combined results enhance the understanding about the role of repertoire calls on species-specific recognition and interbreeding isolation processes (assortative mating), and provide a way to overcome the problem of field identification of female capuchinos at the species level.

Highlights

Females of the Neotropical genus Sporophila are very cryptic, which has limited field research in this group
Despite inter-specific differences based on adult male plumage and song, genomic variation between capuchino seedeaters is minimal (Campagna et al 2017), exemplifying the recent radiation of this Neotropical passerines (e.g., Campagna et al 2010, Burns et al 2014)
There was variation in the rate in which females produced different call types, with some females exhibiting the full repertoire within the first eight recorded calls, whereas others required more than 30 calls to present and equivalent-sized call type repertoire (Fig. 2)

Summary

Introduction

Females of the Neotropical genus Sporophila are very cryptic, which has limited field research in this group. The absence of morphological divergence and a uniform dull brownish plumage, which is common among females in this genus, make the study of this group very challenging (Meyer de Schauensee 1952, Ridgely & Tudor 1989, Ouellet 1992, Sick 1997, Areta et al 2011, Rising et al 2011). There are ten Sporophila (i.e., capuchino) seedeater species, all derived from a common ancestor (Campagna et al 2015, Di Giacomo & Kopuchian 2016) Species within this clade vary little in morphology and size and are notably sexually dimorphic in the coloration of their plumage, with males typically being colorful while females are brownish (Ridgely & Tudor 1989). Some inconsistencies exist in the identification of the capuchinos: hybridization, aberrant plumages, color morphs, individual and seasonal variation of plumage color, and lack of diagnosis of the female by visual observation (Sick 1963 & 1967, Short-Jr. 1969, Ouellet 1992, Areta 2008, Repenning et al 2010b, Areta et al 2011, Areta & Repenning 2011)

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