Wildlife of Grasslands & Oak Woodlands

The Willamette Valley continues to support a rich diversity of mammals, birds, herpetofauna, and invertebrates. Of the 750 wildlife species occurring in the Pacific Northwest, approximately 250 vertebrates use Willamette Valley grassland or woodland habitats.

Nevertheless, there is cause for concern about the future for many species closely associated with native prairies, savannas, and Oregon white oak woodlands. The large carnivores such as the gray wolf and grizzly bear were extirpated from the Valley soon after European settlement. Other species that were once common such as Lewis' woodpecker, streaked horned lark, and black-tailed jackrabbit are now very rare. Twenty wildlife species that occur in Willamette Valley grasslands or oak communities are listed as USDA/USDI Interagency special status/sensitive species, species of concern by the U.S. Fish and Wildlife Service and/or are Oregon Conservation Strategy species. Two species are listed as endangered (Fender's blue butterfly) or threatened (Columbia white-tailed deer) under the federal Endangered Species Act.

Historical records indicate that at least 24 butterfly species were associated with upland prairies in the Willamette Valley , of which 13 species are extinct or exist only as isolated populations

Our synthesis report describes the native wildlife communities that depend upon prairie and oak habitats for feeding and reproduction, we identify the species at greatest risk, and discuss the factors causing wildlife declines in the Valley.

Photo credits: Savanna sparrow © Nick Saunders; banner landscape, Gary Kamer/NRCS