Birds of Blaine County : Riparian Point Count Surveys 2005 2006

he presence of bird species in Blaine County in order to improve the planning process. Much of the land under consideration is mixed-grass prairie bisected by small tributary streams of the Milk and Missouri Rivers. In June 2005, fifty-eight point count surveys were conducted on BLM lands in Blaine County, Montana by zoology staff of the Montana Natural Heritage Program. The purpose of the project was to survey riparian habitat on BLM lands for the presence of riparian-associated birds. The survey was designed to generate a complete list of species to be considered in management planning. Seventy-one species of birds were recorded during the point counts, of which 11 species are state Species of Concern: American White Pelican (Pelecanus erythrorhynchos), Swainson's Hawk (Buteo swainsoni), Long-billed Curlew (Numenius americanus), Common Tern (Sterna hirundo), Forster's Tern (Sterna forsteri), Black Tern (Chlidonias niger), Loggerhead Shrike (Lanius ludovicianus), Sprague's Pipit (Anthus spragueii), Lark Bunting (Calamospiza melanocorys), Baird's Sparrow (Ammodramus bairdii), and Chestnut-collared Longspur (Calcarius ornatus) (MTNHP 2004). Six additional species recorded on BLM lands during the field visits, but not during the formal counts, are recognized as state Species of Concern: Ferruginous Hawk (Buteo regalis), Franklin's Gull (Larus pipixcan), Burrowing Owl (Athene cunicularia), Brewer's Sparrow (Spizella breweri), McCown's Longspur (Calcarius mccownii) and Bobolink (Dolichonyx oryzivorus), while two Species of Potential Concern, Great Blue Heron (Ardea herodias) and Baltimore Oriole (Icterus galbula) were also documented in Blaine County during the project, but not during the point count surveys. Finally, an additional two Species of Concern and one Species of Potential Concern have been previously documented in the region by others; Caspian Tern (Sterna caspia), Grasshopper Sparrow (Ammodramus savannarum), and Short-eared Owl (Asio flammeus) and should be considered in resource management plans. Riparian vegetation accounts for less than one percent of the landscape of the western U.S., yet provides habitat to more species of birds, both migratory and resident species, than all other vegetation types combined (Knopf et al. 1988). Riparian areas provide critical food and cover for a host of wildlife species, with species diversity highly dependent on the complexity and availability of riparian habitat (Scott et al. 2003). Riparian zones in the project area were generally dominated by herbaceous vegetation, with little-to-no shrub or tree component. Although a few riparian-associated species were recorded, the majority of the birds observed represent associations with the adjacent upland vegetation communities. The species documented reflect the limited abundance of complex riparian habitat on BLM lands in Blaine County. Many streams in the more northerly portions of the county are slower flowing streams and are likely to have herbaceous-dominant riparian plant communities (P. Hansen, personal communication 2006). Faster flowing streams in the project area are associated with greater topographic relief, and are more likely to support the growth of shrubs and trees. Although cottonwood recruitment may have been sporadic in Blaine County historically, many of the sites surveyed in a recent study revealed relictual stands of plains cottonwood, suggesting a recent history of tree cover (Jones 2003). The combination of irrigation diversions, small dams, and livestock grazing on these small streams will make future tree recruitment even less likely (Jones 2003). The primary conservation need for riparian bird species identified as a result of this project is to survey all stream systems in Blaine County to 1) classify the vegetation cover potential, 2) identify actions necessary to restore natural disturbance regimes (i.e. flooding, fire, grazing), and 3) implement appropriate actions needed to conserve these riparian corridors