subulata) and prairie selaginella (Selaginella densa) are common forbs. Complex but often sparse vegetation communities adjusted to harsh conditions exist at the border between coulees and grasslands and feature species such as mosses, lichens, black greasewood (Sarcobatus vermiculatus), rabbitbrush (Chrysothamnus nauseosus), long-leaved sage, sagebrush (Artemisia frigida), and povertyweed (Monolepis nuttalliana). The endangered in Alberta soapweed (Yucca glauca), mutually dependent upon the yucca moth (Tegeticula yuccasella), also occurs in the area. Fauna Amphibians and reptiles With its combination of grassland, riparian habitat, coulees and badlands, the Milk River Natural Area and Kennedy Coulee Ecological Reserve host a variety of amphibians and reptiles, including rare northern leopard frogs (Rana pipiens), listed as threatened in Alberta and both a Canadian species at risk (SARA) and Committee on the Status of Endangered Wildlife in Canada (COSEWIC) species of special concern, as well as prairie rattlesnake (Crotalus viridis), bullsnake (Pituophis catenifer sayi), western hognose snake (Heterodon nasicus), western painted turtle (Chrysemys picta), garter snake (Thamnophis radix), and the nationally and provincially endangered short-horned lizard (Phrynosoma douglassi), which is at the northern limit of its geographical range here. The northern leopard frog and prairie rattlesnake in particular are indicator species of the ecological health of the Milk River watershed. Birds The natural area, which has been named as an Important Bird Area, is studded with cliffs and eroded sandstone badlands that serve as important nesting and foraging habitat to the area's raptors. Important birds of prey are the golden eagle (Aquila chrysaetos), ferruginous hawk (Buteo regalis), prairie falcon (Falco mexicanus), and burrowing owl (Athene cunicularia), of which the burrowing owl and ferruginous hawk are considered endangered in Alberta, and the prairie falcon, a species of special concern. Raptor populations have experienced rebounds since the 1970s when the insecticide DDT was outlawed, but new concerns about other pesticides and PCBs along with habitat degradation and land use conversion are contributing to the decline of species such as the burrowing owl. The prairie falcon is at its northern range limit in southern Alberta and although populations appear to be stable at present, loss of grasslands and subsequent decline in their prey of ground squirrels may lead to reduced numbers of falcons. Endemic to western North America, the ferruginous hawk is under threatened status nationally and appears to have been decreasing in numbers since at least 1987, possibly due to prey availability, or habitat or land use change; subsequently,