Three-toed woodpecker

Picoides
Black-backed Woodpecker
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Clade:	Inopinaves
Clade:	Afroaves
Order:	Piciformes
Family:	Picidae
Subfamily:	Picinae
Tribe:	Melanerpini
Genus:	Picoides Lacépède, 1799
Species
Picoides tridactylus Picoides arcticus Picoides dorsalis

Picoides is a genus of woodpeckers (family Picidae) found primarily in North America. The plumage in most species is predominantly black and white, brown and white in some southern species, with the male often having a red (or yellow) badge. Their bills are straight and chisel-shaped. Although in the four-toed species, the toes normally have a zygodactyl or yoked arrangement while on the ground, one toe can be rotated forward for climbing. Some species in this genus are three-toed. All species in this genus feed mainly on insects.

Systematics

The genus is in need of revision. Two species which have a somewhat different color pattern, especially on the head and neck - the Striped and the Checkered Woodpecker - have turned out to belong in Veniliornis, a genus most closely related to Picoides. On the other hand, the Smoky-brown Woodpecker (Veniliornis fumigatus) seems to be an early offshoot of Picoides. Its unique coloration (similar to the unrelated Okinawa Woodpecker) would be an adaptation to dense forest habitat, although due to its distinctiveness it is not inconceivable that it belongs into a genus of its own and merely is a case of molecular convergence. The American Three-toed Woodpecker was until recently considered conspecific with the Eurasian one (Sibley & Monroe 1990), and the Lesser Spotted Woodpecker is often placed in the genus Dendrocopos^{[citation needed]}. Indeed, that genus is sometimes merged into Picoides, but this is neither generally accepted nor well supported.

Analysis of mtDNA COI and Cyt b sequences suggests that Picoides is really three genera (Moore et al., 2006). One is a group of small four-toed species and the Eurasian P. minor, whereas the other group unites the larger species and would include the Smoky-brown Woodpecker. The three-toed species consititute a different lineage closer to some species of Dendrocopos.

All three groups are notable for the high degree of convergent evolution in plumage patterns existing between them (Weibel & Moore, 2005; Moore et al., 2006). There are several pairs of species from different groups which are almost alike; the most notable example is the Downy and Hairy Woodpeckers, which are not closely related but independently evolved a plumage pattern that is identical down to minor details.

Three-toed group (Picoides sensu stricto)

• Eurasian Three-toed Woodpecker, Picoides tridactylus
• American Three-toed Woodpecker, Picoides dorsalis
• Black-backed Woodpecker, Picoides arcticus'

In Dryobates

• Downy Woodpecker, Dryobates pubescens
• Nuttall's Woodpecker, Dryobates nuttallii
• Ladder-backed Woodpecker, Dryobates scalaris

In Leuconotopicus

• Red-cockaded Woodpecker, Leuconotopicus borealis
• Smoky-brown Woodpecker, Leuconotopicus fumigatus - formerly in Veniliornis
• Hairy Woodpecker, Leuconotopicus villosus
• White-headed Woodpecker, Leuconotopicus albolarvatus
• Strickland's Woodpecker, Leuconotopicus stricklandi
• Arizona Woodpecker, Leuconotopicus arizonae

References

• Gorman, Gerard (2004): Woodpeckers of Europe: A Study of the European Picidae. Bruce Coleman, UK. ISBN 1 872842 05 4.
• Moore, William S.; Weibel, Amy C. & Agius, Andrea (2006): Mitochondrial DNA phylogeny of the woodpecker genus Veniliornis (Picidae, Picinae) and related genera implies convergent evolution of plumage patterns. Biol. J. Linn. Soc. 87: 611–624. PDF fulltext
• Sibley, Charles G. & Monroe, Burt L., Jr. (1990): Distribution and Taxonomy of Birds of the World Yale University Press. ISBN 0 300 04969 2.
• Weibel, Amy C. & Moore, William S. (2005): Plumage convergence in Picoides woodpeckers based on a molecular phylogeny, with emphasis on convergence in downy and hairy woodpeckers. Condor 107(4): 797–809. doi:10.1650/7858.1 (HTML abstract)

External links

• Integrated Taxonomic Information System: Genus Picoides

This article is part of Project Bird Genera, a All Birds project that aims to write comprehensive articles on each genus, including made-up genera.