Limited Geographic Variation in the Vocalizations of the Endangered Thick-Billed Parrot: Implications for Conservation Strategies

Abstract

The populations of many species are declining worldwide, and conservation efforts struggle to keep pace with extinction rates. Conservation biologists commonly employ strategies such as translocation and reintroduction, which move individuals of endangered species from one part of their range to another. Because individuals from endangered populations are nonexpendable, identifying any potential barriers to the establishment of viable populations prior to release of individuals should be a priority. This study evaluates the potential for learned communication signals to constrain conservation strategies such as reintroduction in an endangered species, the Thick-billed Parrot (Rhynchopsitta pachyrhyncha). We conducted vocal surveys at three geographically distinct breeding populations in the Sierra Madre Occidental of Chihuahua, Mexico. Acoustic analyses utilizing both spectrogram cross-correlations and parameter measurements from spectrograms revealed no significant differences among the three sites in two common call types. Calls did vary among individuals within a site. The apparent lack of significant geographic variation across sampled sites suggests that differences in learned communication signals are unlikely to pose a barrier to the integration of translocated individuals from different populations into newly established populations.

Geographic variation in the vocalizations of Australian palm cockatoos (Probosciger aterrimus)

“…Observed geographical variation in the vocal characteristics of palm cockatoos is comparable to levels of variation recorded from several other species of parrots (Wright 1996;Baker 2000;Bradbury et al 2001;Baker 2003;Bond & Diamond 2005; but see Guerra et al 2008). Variation in short whistles resembles locally convergent calls in gallahs Cacatua roseicapilla, (Baker 2003), yellow-naped amazons Amazona auropalliata (Wright 1996) and ringneck parrots Barnardius zonarius (Baker 2000).…”

Vocal dialects in parrots: patterns and processes of cultural evolution

“…Dialect regions in Yellow-naped Amazons in Costa Rica were not found to be genetically distinct, and instead had patterns of genetic variation in both mitochondrial DNA and microsatellites consistent with high gene flow between dialects (Wright et al 2005; Wright and Wilkinson 2001). Lastly, Thick-billed Parrots that lack geographic variation between populations also appear to be genetically similar across the range (Guerra et al 2008; D. Acosta and T. Wright unpublished data).…”

“…In contrast, virtually all parrot species are considered non-migratory, although they may make considerable movements over the landscape on a daily or seasonal basis while foraging (Toft and Wright 2015). Vocal variation has only been examined in one migratory parrot, the Thick-billed Parrot; no evidence of geographic variation was found in this species (Guerra et al 2008). …”

“…These studies have revealed diverse patterns of geographic variation, including some species with classic mosaic dialects with sharp transitions in structure, some with graded or clinal variation, and some that lack geographic variation entirely (e.g. in parrots Baker 2000; Bradbury et al 2001; Guerra et al 2008; Wright 1996). Even within the subset of species with clear vocal dialects, there is a wide range of spatial scales over which particular variants are shared, ranging from microgeographic variation among neighbourhoods composed of a few territorial males to macrogeographic variation extending over thousands of kilometres (Podos and Warren 2007).…”

Taxonomia e filogeografia do complexo Pionus maximiliani (Kuhl, 1820) (Aves: Psittacidae)

“…Espécies como Calyptorhynchus funereus (Saunders, 1983), Amazona amazonica (Nottebohm, 1970), Amazona auropalliata (Wright, 1996), Barnardius zonarius (Baker, 2000), Eupsittula canicularis (Bradbury et al, 2001), Amazona guildingii (Kleeman & Gilardi, 2005), Myopsitta monachus (Buhrman-Deever et al, 2007), Rhynchopsitta pachyrhyncha (Guerra et al, 2008) e Platycercus elegans (Ribot et al, 2009) …”