Roby Canyon is a small picturesque canyon in the southwestern Black Hills that merges into Boles Canyon near the Wyoming border about 25 miles west of Custer, South Dakota (population 8,000). The lower sections of these canyons in the dry southwestern portions of the Black Hills contain a pine-juniper-shrub habitat that is very limited in South Dakota. This habitat contains an interesting assemblage of birds, including the only South Dakota locale for breeding Virginia’s Warblers. Much of this area occurs on Black Hills National Forest land so it is accessible for birders. A Black Hills National Forest map is helpful to determine precisely what property is public and what is private. This area is particularly fruitful for birding in late spring and summer. These canyons are rather remote from population centers within the state and from the main tourist sections of the Black Hills. Thus, they are not well studied and consequently offer the possibility of some interesting finds. Indeed, the breeding population of Virginia’s Warblers is relatively large and widespread in the lower reaches of these canyons, yet it was unknown until 1997. Rattlesnakes do occur in this area in small numbers, so use appropriate caution when hiking through the brush.

The vegetation consists of a Ponderosa Pine overstory, with a middle layer of Rocky Mountain Juniper, and a shrubby understory of Mountain Mahogany and Skunkbush Sumac. This vegetation mix lines the canyon walls and the walls of draws and box canyons leading into the main canyons. The rims above the canyons are mainly vegetated with the shrub component without the overstory and the canyon bottoms of Boles and adjacent Redbird canyons (the larger canyons in the area) are pasturelands. The elevation of the pine-juniper-shrub habitat extends from about 4,500 to 5,200 feet with the higher elevations in the canyons becoming almost exclusively pine forest. There is limited water in the area except for a few springs. These springs and some areas of the canyon bottoms where there is spring runoff have a shrubby, riparian-type, deciduous vegetation that attracts some birds associated with this type of habitat.

The most notable bird occurring here is Virginia’s Warbler, which has a relatively large breeding population in this area. This is the northeasternmost breeding population of Virginia’s Warbler and is removed from the next nearest known breeding population (near Casper, Wyoming) by over 130 miles. In addition to Virginia’s Warbler, an interesting assemblage of birds occupies this area and species with grassland, shrubland, and montane affinities converge here. Many of the species occurring here are restricted to the Black Hills or other conifer forests in western South Dakota. Of these species, White-throated Swift, Dusky Flycatcher, Violet-green Swallow, Pinyon Jay, Plumbeous Vireo, Yellow-rumped (Audubon’s) Warbler, and Western Tanager occur commonly, making these canyons a good place to search for them. Seven of the nine regularly breeding species of warblers in South Dakota can be found here; only Common Yellowthroat and Black-and-White Warblers do not breed here, although American Redstart is rare. Other birds with western affinities that can be found here include Common Poorwill, Say’s Phoebe, Gray Jay, Clark’s Nutcracker, Rock and Canyon wrens, Mountain Bluebird, Townsend’s Solitaire, and Brewer’s Blackbird. Cooper’s Hawks, Wild Turkeys, and White-winged Juncos can also be found in this area or farther up the canyons. The area has received relatively little birding attention during songbird migration in May and September so we have a lot to learn about the potential for vagrants during migration. Cassin’s Kingbird has been recorded in Boles Canyon on a couple of recent occasions during May and might be a rare, but regular, migrant through the area.