Editor's Note 01/06: On the basis of differences in genetics and voice, New and Old World populations of Three-toed Woodpeckers are now considered separate species, with P. dorsalis the American Three-toed Woodpecker, and P. tridactylus in Europe and Asia. Future revisions of this account will reflect this change.
The Indians dislike this bird. They call it . . . “Tikelklala.” They have a legend that this bird, many ages ago, in a time of famine, devoured his mate, and wiped his claws clean on the back of his head; in proof of which, they point to the yellow mark of the “fat,” which remains till this day.
W. H. Dall and H. M. Bannister 1869: 275
The only woodpecker common to the Old and New Worlds, the Three-toed Woodpecker (formerly known as the Northern Three-toed Woodpecker and the American Three-toed Woodpecker) breeds farther north than any other woodpecker. Currently 8 subspecies (3 Nearctic and 5 Palearctic) are recognized, although recent molecular data have revealed species-level distinctiveness between a subset of the Nearctic and Palearctic subspecies. The Three-toed Woodpecker is similar to other North American Picoides in having a heavy, chisel-like bill and comparable facial markings and similar to the Black-backed Woodpecker (P. arcticus) in having 3 versus 4 toes and an absence of red in all plumages. The distribution of the Three-toed Woodpecker often coincides with that of spruce (Picea spp.) forests; the Black-backed Woodpecker occurs in spruce as well as other coniferous forests, a habitat difference reflected in the distributions of these 2 closely related species. Like the Black-backed Woodpecker, and to a lesser degree the Hairy Woodpecker (P. villosus), the Three-toed is associated with locally abundant insect outbreaks resulting from disturbances (for example, fire). The Three-toed, however, specializes on bark beetles (Scolytidae), while the Black-backed specializes on wood-boring beetles (Cerambycidae). Both species are irruptive, but their irruptions are not necessarily coincident, which may reflect differences in their food preferences.
Most accounts describe this species as tame or “fearless,” but extremely quiet and therefore difficult to locate. It is generally uncommon and local, likely related to its use of insect-infested forest stands. Such characteristics make it difficult to determine population trends of this bird. In North America, however, data suggest that its populations may be declining, while long-term data from northern Europe leave little doubt that populations in Finland and Sweden are indeed declining. The tracking and use of forests damaged by fire, insects, or storms make the Three-toed Woodpecker vulnerable in fragmented forests or those managed for timber. Fire suppression and salvage logging of trees damaged by fire or insects reduces the abundance of the species' favored prey.
Little known in North America, this inconspicuous resident of boreal and montane coniferous for-ests has been well studied in Europe, most comprehensively by Olav Hogstad in Norway and Klaus Ruge in Switzerland. Cramp 1985a and references within provide a thorough summary of the Palearctic subspecies. For this account, information from North America is emphasized, with data from Eurasia used to fill gaps or to highlight differences between Nearctic and Palearctic populations. In North America most accounts are anecdotal, although in eastern North America West and Speirs (West and Speirs 1959) and Yunick (Yunick 1985) summarized the irruption history of the species and Koplin (Koplin 1969, Koplin 1972) and Koplin and Baldwin (Koplin and Baldwin 1970) documented its response to localized insect outbreaks. More recently, Goggans et al. (Goggans et al. 1988) in Oregon and Murphy and Lehnhausen (Murphy and Lehnhausen 1998) in Alaska studied the foraging ecology and habitat requirements of this bird. The paucity of life-history data from North America makes the Three-toed Woodpecker an ideal candidate for further study. Increased awareness of the importance of natural disturbances in forest ecosystems and economic pressure to increase logging has created interest in this woodpecker.