Important Bird Areas

Anza-Borrego Riparian

California

Anza-Borrego Desert State Park, located in extreme eastern San Diego County, is one of the jewels of California's state park system, and at over 600,000 acres, is the largest state park in the U.S. Though sensitive species and unique natural communities are scattered throughout its rugged canyons and bajadas, its riparian habitat, which includes natural groves of California Fan Palm, mesquite bosque, and wet meadows, stand out as being among the most important for birds. Unfortunately, much of this habitat is located on private lands adjacent to the park or within in-holdings inside its boundaries. Four main areas are especially critical:
Lower Willows of Coyote Canyon (Public; 100 acres of willow and fan palm just north of the town of Borrego Springs)
San Felipe Creek ( -private, California State Parks; 8-mile-long section of perennial creek, including over 200 acres of cottonwood/willow habitat and about 30 acres of marsh/wet meadow; along Hwy. 78 just east of Tamarisk Grove Campground)
Vallecito Creek at Campbell Grade (Private; 55 acres of riparian habitat 10 miles southeast of Scissors Crossing)
Vallecito Cienega (Mainly private; 150 acres of mesquite bosque and wet meadow that includes Butterfield Stage Station; five miles downstream of Campbell Grade).

Ornithological Summary

Many of the sensitive species of birds are confined to the private lands within this IBA, making their management challenging. The extensive mesquite bosque at Vallecito Creek supports the largest number of Least Bell's Vireos (50 pr.), and 12-16 pr. occur at the Lower Willows of Coyote Canyon. Summer Tanager was only recently confirmed breeding within the IBA, with an estimated seven pairs along San Felipe Creek in 2000 (fide P. Jorgensen) and scattered pairs elsewhere. In San Diego County, breeding Long-eared Owl is probably most reliable within this IBA, with San Felipe Creek and Vallecito Cienega traditional nesting sites. Vallecito Cienega features summering Northern Harrier, nesting Vermilion Flycatcher and, in winter, Ferruginous Hawk. Brown-crested Flycatcher has recently established itself as a breeder at a golf course in Borrego Springs and was recorded in 2001 on San Felipe Ck., making it a likely future addition to the list of breeding species in this IBA (San Diego Natural History Museum 2002). Long-term bird monitoring at Vallecitos Ck. (see Massey and Evans 1994) provides excellent baseline data for this dynamic ecosystem.

Help us learn more about the birds at this IBA! Enter your birding data online at Calfornia eBird! (http://ebird.org/california/)

Conservation Issues

Agricultural conversion of extremely fragile desert riparian (including mesquite bosque) habitat remains one of the top concerns on private property here, with 100 acres threatened in the Vallecitos area. Impacts from overgrazing (on private lands) have also been noted, which has included vegetation damage and mesquite cutting to "improve" rangeland for cattle. These cattle support a large population of Brown-headed Cowbirds, which have prompted a region-wide trapping program. Region-wide, depletion of groundwater has been a growing concern, with levels in nearby Borrego Valley having recently been estimated dropping at 1.5 feet/year due to urban development in this arid outpost. As with nearly every desert riparian area, exotic species invasion (esp. tamarisk) remains a major concern, and State Parks has devoted substantial resources controlling it.

Ownership

Anza-Borrego Desert State Park, located in extreme eastern San Diego County, is one of the jewels of California?s state park system, and at over 600,000 acres, is the largest state park in the U.S. Four main areas are especially critical:

?Lower Willows of Coyote Canyon (Public; 100 acres of willow and fan palm just north of the town of Borrego Springs)

?San Felipe Creek (? -private, ? California State Parks; 8-mile-long section of perennial creek, including over 200 acres of cottonwood/willow habitat and about 30 acres of marsh/wet meadow; along Hwy. 78 just east of Tamarisk Grove Campground)

?Vallecito Creek at Campbell Grade (Private; 55 acres of riparian habitat 10 miles southeast of Scissors Crossing)

?Vallecito Cienega (Mainly private; 150 acres of mesquite bosque and wet meadow that includes Butterfield Stage Station; five miles downstream of Campbell Grade).

Habitat

Anza-Borrego Desert State Park, located in extreme eastern San Diego County, is one of the jewels of California?s state park system, and at over 600,000 acres, is the largest state park in the U.S. Though sensitive species and unique natural communities are scattered throughout its rugged canyons and bajadas, its riparian habitat, which includes natural groves of California Fan Palm, mesquite bosque, and wet meadows, stand out as being among the most important for birds.