Draining the southwestern portion of the San Bernardino Mountains, the Upper Santa Ana River and its major tributaries (incl. Mill Ck.) pass through a wide variety of habitats before ending in a broad, alluvial wash east of Redlands. At the headwaters, extensive mixed-conifer forests blanket the north-facing slopes, while the south-facing slopes support a mix of grassy Great Basin Sage Scrub and chaparral. The riverbed itself occasionally widens (e.g. near Seven Oaks and Barton Flats), where it then resembles a montane meadow, with lush grasses and willow thickets. Lower down, a mixed woodland of oaks (especially Canyon Live Oak) and Big-cone Douglas-Fir dominates the north-facing slopes. Several interesting microhabitats are present, notably a series of small waterfalls along Mill Creek.

Ornithological Summary

Black Swift is the most famous denizen of this drainage, and the largest colony south of the Sierras is found in waterfalls along Mill Creek and probably elsewhere in the watershed. California Spotted Owls are present in good numbers in the woodland, which supports a full compliment of southern California's montane bird community. One to three pairs of Southwestern Willow Flycatcher have recently been discovered breeding in alders along Mill Creek near the community of Forest Home (Stephenson and Calcarone 1999), and they may do so near Seven Oaks as well, where montane meadow-breeding taxa such as MacGillivray's Warbler and Lincoln's Sparrow (otherwise very rare breeders in southern California) maintain breeding territories in appropriate habitat (Garrett and Dunn 1981).

Conservation Issues

Though this area is largely protected within San Bernardino National Forest, the most sensitive riparian and montane meadow habitat occurs in various private in-holdings and coincident with areas of high recreation use (e.g. campgrounds, OHV use). The rough, dirt road that follows the river east of Angelus Oaks (incl. to Seven Oaks) is probably keeping the habitat from more severe degradation. Brown-headed Cowbirds may represent a threat to the breeding songbirds, and though it is still scarce within the drainage, Arundo and other exotic riparian plants should be closely monitored.

Ownership

This area is largely protected within San Bernardino National Forest.

Habitat

Draining the southwestern portion of the San Bernardino Mountains, the Upper Santa Ana River and its major tributaries (incl. Mill Ck.) pass through a wide variety of habitats before ending in a broad, alluvial wash east of Redlands. At the headwaters, extensive mixed-conifer forests blanket the north-facing slopes, while the south-facing slopes support a mix of grassy Great Basin Sage Scrub and chaparral. The riverbed itself occasionally widens (e.g. near Seven Oaks and Barton Flats), where it then resembles a montane meadow, with lush grasses and willow thickets. Lower down, mixed woodland of oaks (especially Canyon Live Oak) and Big-cone Douglas-Fir dominates the north-facing slopes. Several interesting microhabitats are present, notably a series of small waterfalls along Mill Creek.

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