The taxonomic status of Palearctic and Nearctic populations of northern goshawk Accipiter gentilis (Aves, Accipitridae): New evidence from vocalisations

Abstract

The taxonomic status of the North American and Eurasian populations of northern goshawk A. gentilis has been called into question by recent molecular studies, indicating the need for additional taxonomic study. Vocalisations have long played an important role in diagnosing potentially reproductively isolated groups of birds. The chattering-type call of A. gentilis plays a role in advertisement and pair-contact, making this a suitable basis for taxonomic study of vocalisations. The data set consisted of recordings of the calls of 75 individuals of the Eurasian gentilis-group of A. gentilis, 37 of the North American atricapillus-group of A. gentilis and, for comparison, seven of Henst’s goshawk A. henstii. The three groups showed non-overlapping variation in the duration of call-notes and also showed several other highly significant differences. Discriminant Function Analysis resulted in 100% correct classification of recordings into the three groups. It is here argued that the new bioacoustic data, in combination with previous evidence of morphological, mitochondrial DNA and genomic DNA differences between Eurasian and North American A. gentilis, suggests that two species are best recognised: northern goshawk A. gentilis and American goshawk A. atricapillus. A. gentilis / A. atricapillus add to a growing list of Holarctic temperate zone taxa that have recently been recognised as separate species based on a deep phylogeographic split between Eurasian and North American populations in combination with differences in other characters. This is the first quantitative taxonomic study of vocalisations in Accipitridae.

Sixty-fourth Supplement to the American Ornithological Society’s Check-list of North American Birds

“…Notes.-Formerly (e.g., AOU 1957AOU , 1983AOU , 1998 considered conspecific with A. gentilis, but separated based on vocal and morphological differences (Sangster 2022) and polyphyly of mitochondrial DNA (Kunz et al 2019). Treated as a separate species from A. gentilis prior to AOU (1957), as American Goshawk.…”

Molecular and acoustic evidence support the species status of Anthus rubescens rubescens and Anthus [rubescens] japonicus (Passeriformes: Motacillidae)

“…Traditionally, taxonomy has been based on morphological criteria, as these were the only criteria that could be studied on museum specimens. However, avian species delimitation is now typically based on a body of evidence integrating morphological, acoustic, genetic and other data (e.g., Alström et al 2007Alström et al , 2008Alström et al , 2015aAlström et al , 2016Alström et al , 2021avan Els & Norambuena 2018;Sangster 2022). Vocalizations are especially important in avian systematics as they can reflect species divergence and differentiation (Alström & Ranft 2003) but also directly contribute to reproductive barriers (Price 2008), although differences in vocalizations are not systematically linked to evolutionary divergences (Potvin et al 2013).…”