Hagerman Complex

This site includes the Hagerman WMA, Hagerman National Fish Hatchery, Thousand Springs Preserve, ?Heron Island?, Niagara Springs WMA, and 27 kilometers of the Snake River. This IBA contains many ponds scattered through sagebrush / deciduous tree areas (Hagerman WMA), upland and riparian habitat (Hagerman National Fish Hatchery, Thousand Springs Preserve), and abundant river habitat with a few islands that are used by nesting herons and egrets.

At an elevation of 2,950 feet, Hagerman WMA lies on a flat to gently-sloping river terrace between the Snake River and a lava rock canyon rim. Due to a combination of topography and geography, Hagerman Valley enjoys significantly warmer temperatures than the surrounding region. This allows much of Hagerman WMA?s water to remain ice-free during winter months, attracting thousands of ducks and geese

Ornithological Summary

1a) Heron Island ? Supports breeding colonies of the following species: Great Blue Heron (80 pairs), Black-crowned Night Heron (200 pairs), Snowy Egret (10 pairs), Cattle Egret (10 pairs).

1b) 20,000-25,000 wintering waterfowl concentrated in Hagerman WMA. In recent winters, wildlife biologists have counted as many as 55,000 ducks and 4,000 Canada Geese on WMA ponds, marshes, and waterways.
3) A variety of wading and shorebirds nest at Hagerman WMA, while others stop only briefly before continuing their northward migration. Black-crowned Night Herons, Great Blue Herons, Virginia Rails, American Avocets, and Spotted Sandpipers are just some of these species.
2) 80+ species recorded on Christmas counts each of last 5 years
3) Bald Eagles wintering: 15-20 individuals. Northern Harrier healthy breeding and wintering populations. Northern Goshawk-one overwintering at Thousand Springs Preserve each year. Yellow Warbler-good breeding populations. Yellow-headed Blackbirds?great breeding populations.
4) Spring Creeks/riparian
5) Land is well-protected long-term so potential for long-term studies is high.

Conservation Issues

Introduced plants and animals, including cheatgrass, Russian Olive, European Starling, and House Sparrow are all problems in the Hagerman Complex. Russian Olives are trying to invade ?Heron Island?, but the wet nature of the soil is probably inhibiting their further expansion. Although the IBA itself is in the hands of federal, state, and private conservation groups, recreational development and residential development potential is quite high on adjacent lands. The natural springs at this site are completely dependent on the Snake River Plains aquifer, which is highly susceptible to groundwater contamination, overpumping and drought. Efforts are on-going on the WMA to allocate water to satisfy various needs of users (i.e., agriculture and hatchery). In addition, water pollution problems are being addressed by various government agencies. Other conservation problems in the Hagerman Complex include extensive soil erosion, and potential disturbance of nesting herons and egrets on Heron Island.

Habitat

Climate: mild winters, springfed waters (58? F) stays ice free, little snow. Summers hot and dry.
Hydrology: Many springs, spring creeks and spring fed ponds as well as Snake River. Geology: basalt rock and cliffs overlain by loess soils.
Topography: 200-foot basalt cliffs edge this side of the Snake, with pockets of riparian bottomland and upland benches.
Dominant vegetation: upland-sagebrush/grassland. Riparian: coyote, wood rose, skunkbush sumac, peachleaf willow?harstem bulrush and other emergents.

Hagerman WMA is managed primarily as waterfowl habitat. Natural creeks and ponds, together with constructed ponds and lakes, provide resting, feeding, and nesting areas for waterfowl and fishing opportunities for anglers. A portion of Riley Creek has been diverted to provide supplemental water to many of these ponds. Numerous acres of grasses, alfalfa, and grain crops are planted annually. Left unharvested, these crops provide food and cover for wildlife.

?Heron Island? contains trees of Black cottonwood, coyote willow, and a rare Russian olive. The island is actually two islands close together with a channel in between. The channel is overgrown with coyote willow. The island is flooded in the spring but the trees provide an impressive rookery. The soils are unknown but probably silt and sandy loam.

Land Use

This area is highly valued for recreation/hunting/fishing, is bordered by irrigated agriculture and aquaculture. An estimated 50,000 hours of fishing effort is spent on the WMA annually. The economic value of this effort equals over $500,000 to the economy.