Dryocopus

Pileated woodpecker Dryocopus pileatus, copyright Matthew Paulson.

Belongs within: Picinae.

Dryocopus is a genus of medium-sized to large, predominantly black woodpeckers with a red crown found in Eurasia and the Americas.

Claimants to the crown
Published 22 January 2024

Woodpeckers are among the most recognisable birds of northern temperate forests. Songs have been written about them, cartoons have featured them prominently, proverbs have been inspired by them. And among the most characteristic woodpeckers of them all are the species of the genus Dryocopus.

Lineated woodpecker Dryocopus lineatus, copyright Carlos Eduardo Joos.

Depending on how you count them, Dryocopus is a genus of between six and eleven medium-sized to large woodpeckers. The term ‘logcock’ has been proposed for Dryocopus species (Winkler & Christie 2002) but I don’t know how much usage it has gotten. Representatives of the genus are widespread, found over large parts of Eurasia and the Americas. Most are fairly uniform in appearance: predominantly black in coloration with a red crown forming a more or less prominent crest. In the New World species, a prominent white stripe runs down the sides of the cheeks and neck, often continuing onto the shoulders, and the lineated woodpecker D. lineatus of northern South America also has barred underparts. In contrast, the black woodpecker D. martius of northern Eurasia is almost entirely black except for the red crown (which in females is relatively restricted). The beak is strong with a well-developed chisel tip and the nostrils are hidden by feathers. The tail is long with the tips of the feathers curved forwards ventrally.

Black woodpecker Dryocopus martius, copyright Hiyashi Haka. The mortality of nestling Dryocopus is unusually high (Winkler & Christie 2002) but apparently no-one knows why.

In recent years, some authors have also included three southeast Asian species in Dryocopus that have historically been recognised as a distinct genus Mulleripicus. One of these, the great slaty woodpecker M. pulverulentus, is among the largest of all woodpecker species, reaching half a metre in length and over half a kilogram in weight. Mulleripicus species lack a distinct crest and may or may not have red markings on the head, and may be largely grey rather than black. They also have much less of a chisel tip on the bill. However, they do share some features with core Dryocopus such as the feathered nostrils and a relatively slender, sparsely feathered neck (Winkler & Christie 2002). Both Mulleripicus and core Dryocopus have a diet dominated by ants, breaking into wood to get at their nests. Recent molecular phylogenies have supported a close relationship between the Mulleripicus and Dryocopus species, either as sister clades (Shakya et al. 2017) or with Mulleripicus nested within Dryocopus (Winkler et al. 2014). These phylogenies uniformly support a division of the core Dryocopus between Eurasian and New World clades, with Mulleripicus placed as sister to the Eurasian clade if the core Dryocopus are not monophyletic.

Ashy woodpecker Mulleripicus fulvus, copyright Francesco Veronesi.

Historically, Dryocopus species have been thought related to the American ivory-bill woodpeckers of the genus Campephilus, which are also large black and white woodpeckers that often have red crowns. However, the two genera differ in structural features of the feet and bill, leading to suggestions that their similarities may be misleading. Molecular phylogenies have confirmed these doubts to be justified, with Dryocopus and Campephilus well separated in the woodpecker family tree (Shakya et al. 2017). Instead, Dryocopus is more closely related to the New World genera Celeus and Colaptes. One species long included in Dryocopus, the helmeted woodpecker D. galeatus of Uruguay, was also shown by molecular data to belong instead to Celeus (Benz et al. 2015). So why did these three taxa—Dryocopus, Campephilus and Celeus galeatus—show such strong convergence towards a similar colour pattern? Environmental pressures seem inadequate as an explanation; species of Dryocopus and Campephilus occupy a wide range of habitat types, and often share their range with woodpecker species that do not exhibit such colour patterns. It has been suggested instead that these genera have converged through inter-specific mimicry. Perhaps their similar appearance helps these woodpeckers to avoid conflict with each other, or means that they exhibit similar social signals. However, this suggestion raises questions about just how much benefit mimics might enjoy, and how this applies to species (such as the Eurasian Dryocopus species) which do not share their range with potential mimics.

White-bellied woodpeckers Dryocopus javensis, copyright Attila Steiner.

None of the Dryocopus species are currently regarded as endangered, though they may be uncommon and some, such as the Andaman woodpecker D. hodgei, have restricted ranges. Most Dryocopus species prefer forest habitats, tending to avoid more open country, so populations are vulnerable to deforestation. However, the lineated woodpecker seems to prefer open habitats and survives well in open country. The black woodpecker and the pileated woodpecker D. pileatus of North America have both exhibited population increases in recent decades, and the black woodpecker has spread into many parts of northern Eurasia where it was not previously found. Woodpeckers have been labelled as ‘keystone’ species in their preferred environments, as the cavities they create for nest sites and while hunting for food provide vital refuges for other animals. Much depends on a woodpecker having been there before.

Systematics of Dryocopus
<==Dryocopus Boie 1826B94
    |  i. s.: D. galeatusJT12
    |         D. hodgeiJT12
    |         D. javensisJT12
    |           |--D. j. javensisI92
    |           `--D. j. richardsi Tristram 1879I92
    |         D. schulziJT12
    |--+--D. lineatusBKB15
    |  |    |--D. l. lineatusE52
    |  |    `--D. l. nuperusE52
    |  `--D. pileatusBKB15
    `--+--D. martius (Linnaeus 1758)BKB15, I92
       `--MulleripicusBKB15
            |--M. funebrisBKB15
            `--M. pulverulentusJT12

*Type species of generic name indicated

References

Benz, B. W., M. B. Robbins & K. J. Zimmer. 2015. Phylogenetic relationships of the helmeted woodpecker (Dryocopus galeatus): a case of interspecific mimicry? Auk 132: 938–950.

[B94] Bock, W. J. 1994. History and nomenclature of avian family-group names. Bulletin of the American Museum of Natural History 222: 1–281.

[BKB15] Burleigh, J. G., R. T. Kimball & E. L. Braun. 2015. Building the avian tree of life using a large-scale, sparse supermatrix. Molecular Phylogenetics and Evolution 84: 53–63.

[E52] Eisenmann, E. 1952. Annotated list of birds of Barro Colorado Island, Panama Canal Zone. Smithsonian Miscellaneous Collections 117 (5): 1–62.

[I92] Iwahashi, J. (ed.) 1992. Reddo Deeta Animaruzu: a pictorial of Japanese fauna facing extinction. JICC: Tokyo.

[JT12] Jetz, W., G. H. Thomas, J. B. Joy, K. Hartmann & A. Ø. Mooers. 2012. The global diversity of birds in space and time. Nature 491: 444–448.

Shakya, S. B., J. Fuchs, J.-M. Pons & F. H. Sheldon. 2017. Tapping the woodpecker tree for evolutionary insight. Molecular Phylogenetics and Evolution 116: 182–191.

Winkler, H., & D. A. Christie. 2002. Family Picidae (woodpeckers). In: del Hoyo, J., A. Elliott & J. Sargatal (eds) Handbook of the Birds of the World vol. 7. Jacamars to Woodpeckers pp. 296–555. Lynx Edicions: Barcelona.

Winkler, H., A. Gamauf, F. Nittinger & E. Haring. 2014. Relationships of Old World woodpeckers (Aves: Picidae)—new insights and taxonomic implications. Annalen des Naturhistorischen Museum in Wien. Serie B. Botanik und Zoologie 116: 69–86.

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