Important Bird Areas

Adobe Creek Reservoir

Colorado

Location: The Adobe Creek Reservoir is located near the town of Las Animas in southeastern Colorado.

Vegetation/natural features: The site consists of a lake with an island (known as "Tern Island"), surrounded by shortgrass prairie.

Ownership: State (CO Division of Wildlife, School Board,
State Land Board)
Private (Fort Lyon Canal Company, individuals)

Ornithological Summary

In most years, "Tern Island" is the primary Least Tern nesting site in the state of Colorado. In fact, more Least Terns have nested and fledged at this site than at all other Colorado sites combined. Piping plovers have also nested here in the past (4 nests in 10 years), and may do so again in future dry years. The site serves as a significant migration and staging location for thousands of shorebirds, hundreds of gulls, and up to 100 Black and Forsters Terns.

Research and educational activities:
A Colorado Division of Wildlife biologist monitors nesting terns and plovers at the site each year.

Conservation Issues

Serious threats: invasive plants (cottonwood), non-native plants (tamarisk, cockleburs), and hydrologic changes (e.g., loss of nests to inflow of water)

Minor threats: predators

Potential threats: pollution and loss of states lease of lake with irrigation company

Terrestrial predators known to access the island used by nesting piping plovers and least terns include coyotes, bullsnakes, skunks, raccoons, foxes, and dogs. However, CDOW believes that gulls (and possibly turtles) may apply the greatest predation pressure on least terns and piping plovers at this and other local reservoirs. Burdock and tamarisk have infested the island, threatening the open beach nesting habitat. Excessive water salinity may threaten the water for some species.

Efforts to address threats: Gulls are hazed when found at the area, and fishing line has been strung around nests/colonies, but these measures provide only temporary protection. In winter, cattle are allowed to graze and trample the shorelines of the reservoir to remove vegetation that would otherwise render the site unsuitable to piping plovers and least terns, although the cattle/grazing may be a factor that promotes invasions of exotics. The state cut invasive trees and vegetation from the island in 1993 and 1995-1997, and applied herbicide to the new growth.

Management details: The Colorado Division of Wildlife leases Adobe Creek Reservoir from the Fort Lyon Canal Company. This lease is currently up for renewal, and may not be renewed. The surrounding prairie, a patchwork of State Land Board land, Colorado Division of Wildlife land, and land owned by private individuals, is grazed by cattle. "Tern Island" is State School Board land and is not grazed. Boating is permitted on the lake, however, CDOW sets up temporary closures of "Tern Island" to protect nesting terns and plovers. Buoys and signs notify people of these closures. Adobe Creek Reservoir is a Colorado Watchable Wildlife Area.

Ownership

A Colorado Division of Wildlife biologist monitors nesting terns and plovers at the site each year.

Habitat

The site consists of a lake with an island (known as "Tern Island"), surrounded by shortgrass prairie.

Land Use

Primary nature and wildlife conservation, hunting/fishing, water supply

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