Milk River Canyon and Area (AB004)
Milk River, Alberta
Description du site
The Milk River Canyon and Area is located in southeastern Alberta where it borders the state of Montana. Three parallel drainage systems are contained within this site: the Milk River in the middle, Kennedy Coulee to the southwest, and the Lost River Valley to the northeast. These drainage systems and intervening plains support a diversity of habitats including native grasslands, badlands, coulees, riparian cottonwood groves, sagebrush flats, sand dunes, cliffs, and rocky outcrops. Some of the land, especially in Kennedy Coulee is gently undulating, while other sections have more sharply eroded valley sides.
In addition to this site's significance for birds, numerous other rare flora or fauna are present. The list includes at least 11 plants that are rare in Canada, the nationally vulnerable Eastern Short-horned Lizard (a significant portion of the Alberta population), and the nationally endangered Swift Fox (The Lost River Sensitive Area was a release site for the reintroduction of the Swift Fox). The Milk River Basin also supports a large proportion of Albertas Pronghorn Antelope population, the Plains Hognose and Bull Snakes, along with the Prairie Rattlesnake, Northern Leopard Frog and several rare fish and invertebrates.
Oiseaux
The Milk River Canyon and Area support breeding populations of at least 7 nationally vulnerable, threatened, or endangered species. These species include the nationally endangered Mountain Plover, Burrowing Owl, and Sage Grouse (prairie population); the nationally threatened Loggerhead Shrike (prairie population) and Sprague's Pipit; and the nationally vulnerable Long-billed Curlew, and Ferruginous Hawk. The Mountain Plover has also been designated as a globally vulnerable species. Within this site, many of these species are widespread and specific surveys to estimate their populations have not been completed; it is likely that several of these species occur in significant numbers. Population estimates from the 1980s are available for Mountain Plovers, with as many as 8 pairs being recorded. This is one of the few locations in Canada where this species occurs.
In addition to threatened species, the site supports a significant community of prairie and grassland birds. Species that are largely restricted to the grassland biome (in addition to some of the threatened species listed above) include Prairie Falcon, Willet, Marbled Godwit, Lark Bunting, Baird's Sparrow (significant provincial population), McCown's Longspur, and Chestnut-collared Longspur. As many as 13 Prairie Falcon nesting sites have been noted, although not every site is used every year. Since the Canadian Prairie Falcon population is estimated to contain between 250 and 500 pairs, this is a significant concentration. Also, Common Poorwill are rare but regular at the site.
Enjeux de conservation
Large parts of this site are within the Kennedy Coulee Ecological Reserve and the Milk River Natural Area; the latter is also identified as an Environmentally Sensitive Area. As such, management plans have been written for these areas and vehicular traffic is strictly controlled within some parts of the site. In other parts, where there is no on-site supervision, overuse by recreationalists cannot be easily prevented. In general, the area is very sensitive to disturbance and erosion.
Since native short-grass habitat is preferred by Mountain Plovers, any decrease in grazing would effect the amount of suitable habitat for this species, as would the invasion of taller non-native grasses. On the other hand, some species prefer a less-grazed environment.
Catégories ZICO Habitats Usages Menaces Potencielles ou Existantes Status de Protection
