Date of this Version
The Prairie Naturalist 41(1/2): March/June 2009, pp 63-65
Our observations represent the first documented nesting by the common raven in North Dakota since the late 1800's. Houston (1977) suggested that the expansion of the American crow onto the Canadian prairies was limited by the scarcity of trees for nest sites, which also might have limited the extent of the common raven. Aspen woodland has increased substantially in and around J. Clark Salyer National Wildlife Refuge since European settlement, due primarily to fire suppression and extirpation of large herbivores (Grant and Murphy 2005). Thus, plausibly these increases in woodland habitat might be providing nest sites necessary for the common raven to recolonize the region. Conversely, the common raven is currently a year-round resident in northern McHenry County, in the Turtle Mountains (Bottineau and Rolette counties), and in the Pembina Hills (Pembina and Cavalier counties), areas which represented extensive natural woodland areas prior to settlement of the region. Common raven numbers have increased during the second half of the twentieth century, and the common raven has returned to parts of its previous range (Boarman and Heinrich 1999). Indeed, analysis of Breeding Bird Survey routes from 1966 through 2003 indicates an increasing population trend for the common raven across most of its range in North America. An increase of greater than 1.5% change per year is indicated for neighboring northwestern Minnesota, southern Manitoba, and southeastern Saskatchewan (Sauer et al. 2008). Possibly, these opportunistic Corvids are adapting to and expanding into previously unoccupied habitats.