Bioacoustic and multi-locus DNA data of Ninox owls support high incidence of extinction and recolonisation on small, low-lying islands across Wallacea

Species delimitation within the Glaucidium brodiei owlet complex using bioacoustic tools

“…The innate vocalisations of owls are an important taxonomic indicator of species limits as they are inherited and subject to strong pressure for mate selection in nocturnal birds (King 2002;Gwee et al 2017). Our bioacoustic data reflected a stark contrast between the well-known homogenous four-note song separated only by short pauses from other motifs of the Collared Owlet throughout mainland Asia and the seven-note song widely separated from other motifs uttered by insular populations in Sundaland (Fig.…”

“…Our study leads to a taxonomic division of an important and well-known Asian owl species complex into two resultant species on the basis of bioacoustic and morphological data. It is therefore one of numerous contributions that highlight the importance of bioacoustics as a tool for species delineation in Strigiformes, which are often challenging to identify by plumage due to age-related or ecomorphological variation (König and Weick 2008;Lin et al 2014;Mikkola 2014;Sadanandan et al 2015;Gwee et al 2017). Modern genetic materials of owl species can be difficult to obtain due to their elusive behaviours and ancient genetic materials can be challenging to work with, thus bioacoustics serve as a reliable tool to scan for cryptic diversity in the absence of genetic data.…”

“…At any rate, plumage comparison may be an unreliable species delineation tool for this group of owls and other species delimitation methods such as bioacoustics and genetics should be employed to accurately determine species boundaries within the G. brodiei complex. Furthermore, several studies have shown the pitfalls of relying solely on morphology in owl taxonomy, and the importance of bioacoustics in species delimitation of owls is well documented (König 1994;King 2002;Gwee et al 2017).…”

A Colourful New Species of Myzomela Honeyeater From Rote Island in Eastern Indonesia

“…In our classification of call types, we interpreted an unbroken vocal segment as an "element", whereas a "motif" was taken to be a collection of one to multiple elements that are repeated in an almost identical fashion (Rheindt et al 2011, Harris et al 2014 Vocal parameters were also analysed using Isler et al's (1998) criterion for bioacoustic species delimitation (henceforth referred to as the Isler criterion). The Isler criterion has previously been applied successfully to distinguish among vocally divergent lineages of Asian and AustraloPacific doves, nightjars, bulbuls, owls, and babblers (Sangster & Rozendaal 2004, Rheindt et al 2011, Garg et al 2016, Gwee et al 2017, Cros & Rheindt 2017 (Fig. 3), a bioacoustic comparison using the Isler criterion was not performed based on low sample size across these call types.…”

“…Therefore, some endemic element can be expected in Rote's avifauna even despite its comparatively small size and proximity to Timor (Rheindt 2016). With the general lack of ornithological studies on Rote's avifauna, the great distinctness of several avian taxa on the island remained undetected until recent work recognised Rote Boobook Ninox rotiensis and Rote Fantail Rhipidura tenkatei at the species level , Gwee et al 2017). …”