Integrative taxonomy reveals Europe's rarest songbird species, the Gran Canaria blue chaffinchFringilla polatzeki

Abstract

The conservation of endangered taxa often critically depends on accurate taxonomic designations. The status of the Gran Canaria population of the blue chaffinch Fringilla teydea polatzeki has not been reevaluated since the early 1900s when this taxon was described as a subspecies and combined with the much more common Tenerife blue chaffinch F. t. teydea in a single species. We show that multiple diagnostic differences in plumage, songs, calls and morphometrics distinguish F. t. polatzeki from F. t. teydea. Preliminary playback experiments suggest that F. t. polatzeki is able to discriminate between songs of both taxa. Along with previously reported differences in mitochondrial DNA, these findings show that the blue chaffinches on Gran Canaria and Tenerife represent two distinctive species: F. polatzeki and F. teydea. Gran Canaria blue chaffinch is Europe's rarest passerine species and should be classified as critically endangered. Its long‐term survival in the wild currently depends on a very small (< 20 km2) area in southwest Gran Canaria. Reclassification of Gran Canaria blue chaffinch as a species increases the urgency of ongoing conservation efforts. Our study underscores the critical importance of taxonomic clarification of threatened taxa that are currently classified as ‘subspecies’.

Acoustic, genetic, and morphological analyses of the Canarian common chaffinch complexFringilla coelebsssp. reveals cryptic diversification

“…Such findings supported the description of a new subspecies (R. r. ellenthalerae), occurring in the western islands of La Palma and El Hierro, meanwhile the former subspecies (R. regulus teneriffae) inhabits the islands of Tenerife and La Gomera. In addition, similar scenarios have been documented to occur with the robin Erithacus rubecula, and the blue chaffinch Fringilla teydea in the Canary Islands (Dietzen et al 2003, Lifjeld et al 2016, Sangster et al 2016. Overall, all these results show an interesting pattern at species level of independent but repeated bouts of colonisation from the continental areas to the Canaries, with subsequent processes of genetic isolation (and sometimes of extinction) producing new taxa over time.…”

Equilibrium Bird Species Diversity in Atlantic Islands

“…The taxonomy and status (endemic/non-endemic) of many Macaronesian taxa is 'work in progress' by the ornithological community, as more morphological and molecular studies become available [43,56]. To account for taxonomic uncertainty, we analyzed datasets assuming three alternative classification schemes: 1) 'conservative' classification, based on the Clements checklist [57], which does not confer species status to many Macaronesian endemic taxa; 2) 'current', which takes into account recent molecular and morphological results from Macaronesian bird studies [43]; and 3) 'phylogenetic', under which we consider as endemic species cases where a taxon from an archipelago forms a well-supported monophyletic group older than 1 Ma on our maximum credibility BEAST trees.…”

Acoustic analysis and playback experiments do not support the taxonomic revision of the Central and Western Canary Islands subspecies of the Eurasian Stone-curlew (Burhinus o. distinctus)

“…The status of Canarian subspecies is particularly intriguing as several cases of cryptic differentiation of local birds has been discovered in recent years which induces to consider the number of endemic species in the archipelago as probably underestimated (Illera et al . 2016, 2018, Sangster et al . 2016).…”

“…Tietze et al . 2011, Sangster et al . 2016), but they have been also employed to examine how subspecies or closely related species of non-passerines respond to calls recorded in different geographical locations (e.g.…”