Monday, 23 September 2013


Green Woodpecker (Picus viridis). On the left, head of a male viridis from central Europe.  On the right, head of a male sharpei from the Iberian peninsula. The black mask, present in the fomer, is the male morphological difference. In both cases the female does not have red in the moustache.

How many species of birds are there? Well it depends on which list you use and which criteria they use to compile the list. Among the many world lists of birds that are available, the IOC World Bird List is one of those with the most followers, being the one being kept continually up-to-date. One of the recent changes was their validation as a full species the Iberian Green Woodpecker  (Picus sharpei)- or perhaps it should just be called Iberian Woodpecker, which has traditionally be considered as a subspecies of the Green Woodpecker (Picus viridis). The scientific basis for this change are the studies of Pons et al. 2011 and Perktas et al. 2011.

The use of molecular techniques has brought about a revolution in the taxonomy (classification) of birds. Thu8s, some Iberian species have recently been elevated to full species level, as has been the case with the Spanish Imperial Eagle (Aquila adalberti), Iberian Chiffchaff (Phylloscopus ibericus) and Iberian Grey Shrike (Lanius meridionalis). One of the Iberian endemics most recently accepted has been the Iberian Magpie Cyanopica  cooki). The case of the Green Woodpecker is less well known, although its taxonomic status has been subject to debate for many years, indeed there are field guides which have already treated sharpei as a separate species in Iberia (Aves de Europa de Barthel y Dougallis, 2008). However, one will need to wait to see if other lists, including the official SEO Spanish List will also take this proposal into consideration.

The main study setting out the proposed change (Pons et al., 2011) looked at the evolutionary history of the Green Woodpecker complex in the western Palaearctic.  The results provided evidence of three genetic lineages, which coincided with differences in plumage, especially head pattern, and voice.  A North African lineage (vaillantii), split about 1.6 to 2.2 million years ago, the European  (viridis) and a third Iberian form (sharpei). These two separated about 0.7 to 1.2 million years ago, during a glaciation, when they probably occupied refuges in South-Eastern Europe (Italy, the Balkans and Anatolia) and in Iberia respectively.  Following the glaciation, both forms expanded northwards and established contact in southern France, where today there is a certain gradation (the plumages of the three forms as well as intermediates can be seen in Copete, 2011). Neither the Iberian nor the North African forms have Spanish names. Both populations are highly sedentary. There are no ringing recoveries of Green Woodpeckers (viridis) in Spain, nor Iberian birds in other countries. Almost all of the controls occur at the site of ringing, with the longest displacements being a bird from Cuenca recovered at the coast in Cádiz, another from Ciudad Real on the coast in Valencia and a bird from Burgos on the Cantabrian coast  (SEO/BirdLife).

The second study (Perktas et al. 2011) has similar results as the former and furthermore suggests the presence of a fourth species in the Middle-East (Iran).

- J.M. Pons, G. Olioso, C. Cruaud & J. Fuchs. 2011. Phylogeography of the Eurasian green woodpecker (Picus viridis). Journal of Biogeography, 38:311-325. [summary]
- U. Perktas, G. F. Barrowclough & J. G. Groth. 2011. Phylogeography and species limits in the green woodpecker complex (Aves: Picidae): multiple Pleistocene refugia and range expansion across Europe and the Near East. Biological Journal of the Linnean Society, 104:710-723. [summary]
- G. Olioso y J.M. Pons (2011). Variation géographique du plumage des Pics verts du Languedoc-RoussillonOrnithos 18(2): 73-83