An evidence-based overview of hybridization in tinamous

Jente Ottenburghs

doi:10.1007/s43388-021-00049-y

Abstract

Estimates suggest that about 16% of bird species hybridize in the wild. This number is based on two main sources: the Handbook of Avian Hybrids of the World by Eugene McCarthy and the online Serge Dumont Bird Hybrids Database. Although both sources provide supporting references for the documented hybrids, the reliability of these references has not been systematically assessed. In this paper, I introduce a scoring scheme based on three criteria that are weighted based on their reliability, namely field observations or photographs (1 point), morphological analyses (2 points), and genetic analyses (3 points). The final tally of these three criteria (ranging from 0 to 6 points) will indicate the level of confidence for a particular hybrid. I test this scoring scheme on the Neotropical bird family Tinamidae (tinamous), in which several putative hybrids have been reported. My analysis revealed one well-documented case (Crypturellus boucardi × C. cinnamomeus) and three doubtful records that require further investigation. These findings highlight the need for thoroughly scrutinizing the sources supporting avian hybrids. The scoring system clearly illustrates its usefulness and can be easily applied to other taxonomic groups to increase the reliability of documenting interspecific hybrids.

Highlights

Hybridization refers to the situation where species “that are distinguishable on the basis of one or more heritable characters overlap spatially and temporally and cross to form viable and at least partially fertile offspring” (Arnold 1997)
This phenomenon is rare on an individual level, hybrids between numerous bird species have been documented (Justyn et al 2020; Ottenburghs and Slager 2020)
Additional searches on Web of Science and Google Scholar did not uncover other hybrids. In addition to these four cases, McCarthy (2006) mentioned a parapatric contact zone between Brown Tinamou (C. obsoletus) and Traylor’s Tinamou (C. traylori, considered a subspecies of C. obsoletus) in Peru, but he noted that no hybrids have been reported

Summary

Introduction

Hybridization refers to the situation where species “that are distinguishable on the basis of one or more heritable characters overlap spatially and temporally and cross to form viable and at least partially fertile offspring” (Arnold 1997) This phenomenon is rare on an individual level, hybrids between numerous bird species have been documented (Justyn et al 2020; Ottenburghs and Slager 2020). According to the latest estimates, about 16% of bird species has hybridized with another species (Ottenburghs et al 2015) This percentage is primarily based on two sources: the Handbook of Avian Hybrids of the World (McCarthy 2006) and the online Serge Dumont Bird Hybrids Database (Dumont n.d.). Both sources provide abundant references for the reported hybrids, but the reliability of these references has generally been taken at face value.

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Conclusion