Alameda Whipsnake

Masticophis lateralis euryxanthus

Description

The Alameda whipsnake (or Alameda striped racer), a member of the family Colubridae, is a slender, fast-moving, and diurnal snake with a narrow neck and a relatively broad head with large eyes. The dorsal surface is colored sooty black with a distinct yellow-orange stripe down each side. The anterior portion of the ventral surface is orange-rufous colored, the midsection is cream colored, and the posterior and tail are pinkish. Adults range in length from 3-4 ft (1-1.3 m)

The Alameda whipsnake is distinguished from the chaparral whipsnake (Masticophis lateralis lateralis ) by its sooty black dorsum, by wider yellow-orange stripes that run laterally down each side, the lack of a dark line across the rostral, an uninterrupted light stripe between the rostral and eye, and the virtual absence of spotting on the venter of the head and neck.

Behavior

This extremely fast-moving snake holds its head high off the ground to peer over grass or rocks for potential prey and is an active diurnal predator. Its diet includes lizards, small mammals, snakes, and nesting birds. Alameda whipsnakes breed from March through June, with mating appearing to occur near the hibernacula of the female. Whipsnakes lay clutches of six to 11 eggs from May through July, and the young hatch and emerge in the late-summer to early-fall. Radiotelemetry data suggest that Alameda whipsnakes can occupy home ranges varying in size from 1.9 to 5 to 21.5 acres (0.76 to 2 to 8.6 hectares).

Home ranges of marked snakes overlapped. Some animals were recorded to have moved over 1 mi (1.6 km) while crisscrossing their areas.

Habitat

The Alameda whipsnake is typically found in northern coastal scrub, coastal sage scrub and chaparral plant communities, but it may also occur in adjacent grasslands and oak and oak/bay woodlands. They demonstrate a preference for open-canopy stands and habitats with woody debris and exposed rock outcrops, and they tend to be found on southeast, south, and southwest facing slopes.

Distribution

The Alameda whipsnake inhabits the inner Coast Ranges in western and central Contra Costa and Alameda counties. Urban development has fragmented the originally continuous range of this snake into the Tilden-Briones, Oakland-Las Trampas, Hayward-Pleasanton Ridge, Mount Diablo-Black Hills, and Sunol-Cedar Mountain populations. These names cover the following respective geographical areas: from the Sobrante Ridge, Tilden/Wildcat Regional Parks area to the Briones Hills, in Contra Costa County; from the Oakland Hills, Anthony Chabot area to Las Trampas Ridge, in Contra Costa County; from the Hayward Hills, Palomares area to Pleasanton Ridge, in Alameda County; from the Mount Diablo vicinity and in the Black Hills, in Contra Costa County; and from the Wauhab Ridge, Del Valle area to the Cedar Mountain Ridge, in Alameda County. These populations all occur on private and non-Federal land.

Due to the fragmentation of the range of the Alameda whipsnake, little or no interchange occurs among the five populations. The ability of the whipsnake to interchange among the first three populations described above is contingent on their dispersing over the Caldecott Tunnel in Contra Costa County and under Highway 580 in Alameda County at the Eden Canyon interchange, the Dublin Boulevard undercrossing, or where San Lorenzo Creek passes under the highway. The ability of the Alameda whipsnake to interchange between the Hayward-Pleasanton Ridge and Sunol-Cedar Mountain populations depends on their dispersing along Alameda Creek in Alameda County and crossing under Highway 680 where the creek passes under the highway, crossing under the highway at Scott's Corner along Vallecitos Creek, or where two unnamed tributaries to Arroyo de la Laguna cross under Highway 680 north of Scott's Corner. The Mount Diablo-Black Hills population has no path for dispersal to any of the other populations.

Threats

The Alameda whipsnake and its associated northern coastal scrub and chaparral habitats are threatened by fire suppression and related wildfire problems associated with lack of fuel reduction, and also by urban development, genetic isolation, and excessive livestock grazing. Although these factors are significant threats to the status in the wild of the whipsnake, they are not thought to currently threaten the survival of this species. However, the rate of loss of suitable habitat on private lands and the failure to implement appropriate fire management practices on public lands to sustain suitable habitat make it likely that the Alameda whipsnake will become endangered in much or all of its range in the foreseeable future.

Overall urban development and associated damages have resulted in the loss of about 30 of the 55 known historical localities for the Alameda whipsnake. Urbanization and associated highway and road construction have fragmented the range of the Alameda whipsnake into five isolated populations, each of which consists of several to numerous sub-populations with varying degrees of connectivity. The five populations occur on fairly large expanses of non-Federal public land, which comprise about 80% of known whipsnake habitat. Although these public lands are protected from development, other threats to the whipsnake remain. These include the negative effects of fire suppression on whipsnake habitat, and increased recreational use of public lands (an indirect consequence of urban development elsewhere).

A number of native and introduced mammals and birds are predators of the Alameda whipsnake. Native predators include the California kingsnake, raccoon, striped skunk, opossum, coyote, gray fox, and various hawks. Urbanization can increase the abundance of some of these natural predators and make easier their access to snake-occupied habitat. In addition, some non-native predators are taking a toll of the Alameda whipsnake, including the red fox, rats, feral pigs, and feral and domestic cats and dogs. These alien predators become particularly important where urban development abuts whipsnake habitat. A movement to maintain feral cats in parklands is an additional potential predation threat.

The Alameda whipsnake is threatened directly and indirectly by the effects of fire suppression. Fire suppression results in the buildup of highly flammable underbrush and woody debris, creating conditions for slow-moving, intensely hot fires that degrade habitat and kill whipsnakes. Fire suppression has also led to the encroachment of alien trees and shrubs into grassland habitats, further increasing flammable fuel loads. Fire suppression also degrades snake habitat by allowing the establishment of closed-canopy vegetation that is less favorable than open conditions.

Conservation and Recovery

The California Environmental Quality Act and California Endangered Species Act afforded the Alameda whipsnake some conservation benefits prior to its being Federally listed, but these laws by themelves were far from adequate to protect the species. The listing of the Alameda whipsnake as a Federally threatened species will increase the ability of public land agencies to promote conservation and management plans that take into consideration the specialized environmental and biological needs of this snake. These plans include an increased ability to conduct prescribed burns throughout the whipsnake's range; control native, introduced, and feral predators; regulate recreational use; and develop educational programs for the benefit of the Alameda whipsnake. With appropriate management, areas of open space managed by the East Bay Regional Park District, East Bay Municipal Utilities District, and Mount Diablo State Park may be better utilized to protect the Alameda whipsnake.

Contact

U.S. Fish and Wildlife
Service Sacramento Fish and Wildlife Office
2800 Cottage Way, Room W-2605
Sacramento, California 95825-1846
Telephone: (916) 414-6600
Fax: (916) 460-4619

Reference

U.S. Fish and Wildlife Service. 8 March 2000. "Endangered and Threatened Wildlife and Plants; Proposed Determination of Critical Habitat for the Alameda Whipsnake (Masticophis lateralis euryxanthus )." Federal Register 65 (46): 12155-12181.