Montana Field Guide

Black-backed Woodpecker - Picoides arcticus

Black-backed Woodpeckers are at the large end of the medium-sized woodpeckers. At 9.5 inches in length, only the flickers and Pileated Woodpeckers (Dryocopus pileatus) are larger. Adults are similar in size and in appearance except for the yellow crown present only on the males. The back of the head, neck, back, and wings (upperparts) are all black and the chin, throat, breast and belly (underparts) are white. The sides and flanks are also white with heavy black barring. A strong white line runs below the eye from the bill to the nape (Dixon and Saab 2000). The wing primaries are barred black and white and only the outer tail feathers (rectrices) are white; otherwise the tail is black. Juvenile birds are similar in appearance but much duller overall. They have a plain black crown, with no, or nearly no, crown patch, and a washed out or buffy look to the underparts. Black-backed Woodpeckers, like Three-toed Woodpeckers (Picoides tridactylus), have only 3 toes on each foot rather than the normal 4 toes (Dixon and Saab 2000).

The call note, a single metallic "kyik" or "chet" (similar to Hairy Woodpecker, Picoides villosus) helps to detect the Black-backed Woodpecker. They also use a unique agonistic "wet-et-ddd-eee-yaaa," or "scream-rattle-snarl" call in association with a hunched wing-spreading display (Short 1974). Drumming is variable (fast or slow) in long, even rolls (Farrand 1983, Goggans 1989). Drumming is described as coming in 2-second bursts tapering off at the end, at intervals of 30 to 40 seconds, suggestive of Pileated Woodpeckers. They also give single raps when nervous or about to roost (Kilham 1966).

Having only three toes on each foot and, in males, having a yellow crown patch instead of red, distinguishes Black-backed Woodpeckers from all other woodpeckers except Three-toed Woodpeckers (Dixon and Saab 2000). The all-black head and back are diagnostic of Black-backed Woodpeckers. Three-toed Woodpeckers have at least some white on the back. Also, the white line under the eye is broader in Black-backed Woodpeckers; Three-toed Woodpeckers have a slimmer white line below the eye as well as another white line behind the eye. The yellow crown patch is smaller and solidly yellow in Black-backed Woodpeckers rather than larger and rather streaked in Three-toed Woodpeckers. Female Black-backed Woodpeckers have a solid black forehead and crown, which is unlike the streaked and white speckled forehead and crown of Three-toed Woodpeckers (Dixon and Saab 2000).

Montana Range

Black-backed Woodpeckers are a resident species in Montana, where their breeding range encompasses their year-round range. Black-backed Woodpeckers have been observed during almost every month of the year, except for January and February, which is probably due to the lack of observers during these months. Also, non-breeding season observations are almost always located in the same areas of the state where breeding and potential breeding records have been documented (MBD 2003). This indicates the species does not normally move outside of its usual breeding range during the winter.

The habitat of Black-backed Woodpeckers in Montana is early successional, burned forest of mixed conifer, lodgepole pine, Douglas-fir, and spruce-fir (Hutto 1995a, 1995b), although they are more numerous in lower elevation Douglas-fir and pine forest habitats than in higher elevation subalpine spruce forest habitats (Bock and Bock 1974). This is supported by Harris (1982) who found Black-backed Woodpeckers in two recently burned forests comprised of 73% and 77% Douglas-fir, respectively. They appear to concentrate in recently burned forests and remain for several years (3 to 5) before leaving due to prey source decline (Harris 1982). In northwestern Montana, Black-backed Woodpeckers nested in areas of western larch (Larix occidentalis)/Douglas-fir forest with a major component of old-growth (McClelland et al. 1979). Harris (1982) found Black-backed Woodpeckers nesting within western larch even though the stand was predominately Douglas-fir. McClelland et al. (1979) determined the decay of heartwood while maintaining a hard outer shell of western larch creates an ideal nesting site for Black-backed Woodpeckers to excavate.

The bulk of the diet of Black-backed Woodpeckers is wood-boring beetle larvae (including Monochamus spp. and Englemann spruce beetle, Dendroctonus englamanni), but they also feed on other insects (e.g., weevils, beetles, spiders, ants). Occasionally they will eat fruits, nuts, sap, and cambium (Wickman 1965 and Baldwin 1960, cited in Bull et al. 1986, Short 1974, Scott et al. 1977, Terres 1980). Black-backed Woodpeckers may be attracted by the clearly audible chewings of wood-boring insects in recent burns (Taylor and Barmore 1980).

Black-backed Woodpeckers obtain food by flaking bark from trees (usually dead conifers) and logs, sometimes by picking gleaning. They feed primarily on logs and low on large-diameter tree trunks (more than 7.5 centimeter diameter at breast height; but most often 15-25 centimeter dbh) (Short 1974, Villard 1994). Harris (1982) found that females foraged higher on trees than males. Females feed young more often than males, but carry less food in each visit. Although males visit less often they come with more food, and perhaps supply 50 percent to 75 percent of food to nestlings (Short 1974, Kilham 1983).

Foraging in western Montana was primarily by pecking, with scaling the next most common technique (Harris 1982); most feeding was by scaling in Oregon (Bull et al. 1986). Harris (1982) found males foraged lower on the tree than females. Harris (1982) compares the ecology of Black-backed, Three-toed, and Hairy Woodpeckers. Size of the home ranges of 3 indivuals in Oregon was 178, 307, and 810 acres; home range size varied inversely to proportion of unlogged and mature/old-growth habitat (Goggans et al. 1989). They maintain intraspecific territories, but have overlapping home ranges with other woodpecker species (Goggans et al. 1989).

In general, Black-backed Woodpeckers are intraspecifically territorial. In Oregon, the home range size for three individuals was 72, 124, and 328 hectares; small home range size was associated with abundant mature/old-growth timber (Goggans et al. 1988). In the Sierra Nevada Range in California, densities were estimated at 0.2 pair per 40 hectares (Raphael and White 1984). In northeastern and north-central forests, territory size is estimated at 30 hectares and the maximum density is 3.3 pairs per 100 hectares (Evans and Conner 1979). In Idaho, the home range of one male in the breeding season was 72 hectares (Dixon and Saab 2000). In Vermont, the home range size was reported to be 61 hectares (Lisi 1988).

Black-backed Woodpeckers are highly responsive to forest fire and other processes, such as spruce budworm outbreaks, resulting in high concentrations of wood-boring insects invading dead trees. Local and regional irruptions and range extensions have been observed in response to burns and wood-borer outbreaks (West and Spiers 1959, Bock and Bock 1974, Kingery 1977, Yunick 1985).

Very little information regarding Black-backed Woodpecker reproduction is currently available for Montana, as few nesting studies have been completed. Information gathered from other sources likely relevant to reproduction of Black-backed Woodpeckers in Montana state that they nest in late spring and early summer. Pair bonding and courtship begin in April and nest excavation begins in early May (Goggans 1989, NSMNH 1999). Clutch size is two to six (usually four). Incubation, by both sexes, may last 12 to 14 days. Young are altricial, tended by both parents and fledge in about 25 days (Ehrlich et al. 1988). In Oregon, the success rate for 19 nests was 63 percent (Goggans et al. 1989).

No known active management is ongoing for Black-backed Woodpeckers in the state. However, studies from the western United States on the logging of post-fire trees indicated the negative impacts of this activity on Black-backed Woodpeckers (Kotliar et al. 2002). The conclusion reached was that this species rarely used even partially logged post-fire forests. Therefore, when salvage logging is planned, a delay of work for at least five years after the disturbance event is very important (Hutto 1995, Dixon and Saab 2000). This time delay is essential to provide habitat as the woodpecker's main prey items (wood-boring beetles) become less abundant after this period (Caton 1996). Salvage operations should retain more than 104 to 123 snags per hectare (more than 42 to 50 snags per acre) that are more than 23 cm diameter at breast height (dbh), more than 9 inches dbh (Dixon and Saab 2000, Wisdom et al. 2000).