Dryocopus

Abstract: This is a quantitative study of population changes in four non-migratory woodpeckers in Sweden. Data were collected during five periods from late autumn to spring and during the breeding season, mainly using point counts. Most analyses are based on the proportion of the routes (each with 20 points) with observation of the species in each year. From 1975 to 1991 there were no population trends in the Great Spotted and Black Woodpeckers, but decreases in the Green and Lesser Spotted Woodpeckers. The mean annual decrease was about 2% in the Green and 4% in the Lesser Spotted Woodpecker. There was no trend in winter weather over this period, and only for the Black Woodpecker we found associations between mild winters and numbers recorded. The Great Spotted Woodpecker population increased in years with a high spruce seed supply. In southernmost Sweden frequency of observation was higher for the Green and, in winter, for the Black Woodpecker than further north, while the reverse was true for the Great Spotted Woodpecker. No regional difference was found for the Lesser Spotted Woodpecker.

Abstract: Examples of phenotypic convergence in plumage coloration have been reported in a wide diversity of avian taxonomic groups, yet the underlying evolutionary mechanisms driving this phenomenon have received little scientific inquiry. We document a striking new case of plumage convergence in the Helmeted Woodpecker (Dryocopus galeatus) and explore the possibility of visual mimicry among Atlantic Forest woodpeckers. Our multilocus phylogenetic analyses unequivocally place D. galeatus within Celeus, indicating that the former has subsequently converged in appearance upon the distantly related and syntopic Dryocopus lineatus, to which it bears a remarkable resemblance in plumage coloration and pattern. Although details of the Helmeted Woodpecker's ecology and natural history are only now beginning to emerge, its smaller size and submissive behavior are consistent with predictions derived from evolutionary game-theory models and the hypothesis of interspecific social-dominance mimicry (ISDM). Moreover, e...

Abstract: The Helmeted Woodpecker Dryocopus galeatus is a threatened species of the Atlantic Forest in southeastern South America. It has traditionally been placed in the genus Dryocopus, but it shows similarities in plumage and structure with woodpeckers in the genus Celeus. We sequenced mitochondrial and nuclear DNA that was sampled from live captured Helmeted Woodpeckers. We found that the Helmeted Woodpecker has a phylogenetic position embedded within the genus Celeus, and recommend its taxonomic treatment as Celeus galeatus. The Helmeted Woodpecker belongs to a clade within Celeus that includes Kaempfer’s Woodpecker C. obrieni, Rufous-headed Woodpecker C. spectabilis, and Cream-coloured Woodpecker C. flavus. It has the southernmost distribution range of the woodpeckers in this clade. The Helmeted Woodpecker is sympatric throughout its range with Lineated Woodpecker Dryocopus lineatus and Robust Woodpecker Campephilus robustus and these species from three different genera show a remarkable convergence in plumage colours and patterns. With the inclusion of Helmeted Woodpecker in Celeus, this genus has four out of 15 species on the International Union for Conservation of Nature (IUCN) red list, a higher proportion of red listed species than in the woodpecker family overall.

Abstract: damage poles, and few, if any, of these species are destructive throughout their respective ranges. Turcck (1960), on the basis of correspondence and his observations, as well as sources from the literature, delimits the areas of woodpecker attack in Europe and Asia. It isn't entirely clear, however, whether he has found woodpecker damage to poles to exist only in countries specifically mentioned, or if he implies wider occurrence when he states in his summary that "damaged wooden poles are found throughout the whole Holarctic region." Old World countries specifically reported by Turcck to have this problem are Sweden, Finland, Czechoslovakia, Hungary, the U. S.S. R., and Japan. Genera involved are Dryocopus and Dendrocopos. Woodpecker attack upon utility poles has probably been better documented and known for a longer period of time in North America. During the last century, Scnnctt (1879) commented upon the severity of attack in south Texas. Many others took note of damage by woodpeckers during the early days of the communications industry when most poles carried telegraph wires. Not until 1911 was the problem seriously diagnosed by researchers. This year was important for the appearance of three papers: one on the damage caused by woodpeckers (McAtec, 1911), one on the food of woodpeckers (Bcal, 1911), and one on the effect of woodpecker damage to pole strength (Weiss in McAtcc, 1911). No solution to the problem appeared during the early part of the century. Apparently in this day before laws protecting woodpeckers and other birds, the chief recourse was in shooting the offenders. McAtcc, although noting that creosote as a pole preservative did