Rocky Mountain Arsenel National Wildlife Refuge

Background | Criteria | Northwest Colorado | Northeast Colorado
Southwest Colorado | Southeast Colorado

Rocky Mountain Arsenal
National Wildlife Refuge
Adams County

Size: 17,000 acres

Elevation: 5138 - 5250 feet

Habitats: Primary – grassland

Secondary – lowland riparian, open water, sagebrush shrubland, wetlands

Ownership: Federal (U.S. Fish & Wildlife Service)

Land Use (post clean-up):

Primary – nature and wildlife conservation

Secondary – fishing, recreation/tourism

IBA Criteria: 1, 2, 4 (waterfowl, raptors)

Site description

Location: Rocky Mountain Arsenal National Wildlife Refuge is surrounded on three sides by Commerce City, Montbello, and Denver International Airport in central Colorado.

Vegetative/natural features: Production of weapons, nerve agents, and agricultural pesticides occurred on the property from 1942-1969. A large buffer zone of abandoned cropland with remnant native prairie, manmade lakes, and planted trees surrounded the weapons factory. Current habitats include upland trees and shrubs (1%), shrubland and succulents (3%), wetland/riparian (5%), and native perennial grasslands (20%). The remaining 71%, consisting of weeds and grasses, will be restored to shortgrass prairie vegetation, including 4500 acres of prairie dog towns.

Ornithological Importance

Observers have recorded over 200 species of birds at the site. Single day spring counts average near 90 species. As the Front Range continues to be developed, this site will become even more important to breeding and migratory birds.

Breeding species:	Average #	Maximum #
Burrowing Owl	36 nests	68 nests
Swainson’s Hawk	10 nests	14 nests

Migrant species:	Average #	Maximum #
Redhead	2,500 (spring)	4,134 (spring)

Wintering species:	Average #	Maximum #
Bald Eagle	64	81

Conservation/Management Issues

Serious threats:
1. invasive/non-native plants (which colonized the buffer zone around the former weapons factory).

Minor threats:
1. pollution of soils and lakebeds around the factory (which has resulted in some bird deaths).

Potential threats:
1. development along refuge boundaries.

Efforts to address threats:
Clean-up of the site has reduced bird mortality from soil and water contamination. Land managers make great efforts to minimize bird disturbance during clean-up.

Management details:
This former military and industrial manufacturing site is being cleaned-up and restored, and will subsequently be managed by the U.S. Fish & Wildlife Service as a National Wildlife Refuge. Access to the site is being controlled during clean-up. Following this 10-15 year clean-up period, the public will enter via a refuge form of transportation which they can leave and return to at designated trails. This plan is designed to minimize disturbance to wildlife while allowing opportunities to view them. Rocky Mountain Arsenal is a Colorado Watchable Wildlife site.