Alameda whipsnake

The Alameda whipsnake is a diurnal ectotherm that is often seen foraging in the daytime. As it searches for food, the head and the front half of the body are held off of the ground for the most optimal vision to find prey. The snake has two seasonal peaks in activity, one during the spring mating season and the other during late summer or early fall. In the spring, males tend to forage and search for mates while females stay in hibernation. Female peak activity only tends to be a few days in the spring when they are looking for egg laying sites. When the Alameda striped racer finds prey, such as the Western fence lizard (Sceloporus occidentalis) or the Western skink (Eumeces skiltonianus), it takes the prey quickly, holds it tight under the loops of its body, and swallows it whole without constriction. Alameda whipsnakes are great climbers and are able to quickly move through trees and shrubs to hunt prey or escape predators (US Fish and Wildlife 2006).[2]

Courtship and mating are observed from late March through mid-June. During this time, males move around throughout their home ranges, but females appear to remain at or near their hibernacula, where mating occurs. Female egg laying sites are typically located in grasslands with scattered shrub habitat. Copulation commences soon after emergence from winter hibernacula (Swaim 1994). Females begin laying eggs in mid-late May. Average clutch size is just greater than 7 eggs with a significant correlation between body size and clutch size (Goldberg 1975). Once the female lays her eggs, it will be about 3 months of incubation before the young appear in the late summer and into the fall (US Fish and Wildlife Service 2002).[3][4][5][6]

The Alameda whipsnake is an ectotherm. It might first emerge by sliding its head out of its burrow into the sun. Then it will bask its whole body until its temperature is 91.4-93.4℉. It has two annual peaks in activity. The first extends from March, when it leaves its hibernaculum, until mid-June, following courtship and mating. Hatchlings have been located during the second smaller peak in activity, from August through November. Afterwards, like mature snakes, they will seek out a hibernaculum for winter hibernation. Alameda whipsnakes require 2–3 years to reach maturity, may live for eight years, and can reach a length of five feet. The Alameda whipsnake's home range may have one or more core areas and specific retreats. They are good climbers, and are able to escape into scrub or trees (US Fish and Wildlife 2006).[2][5]

The whipsnake once had a continuous range in the inner Coast Ranges in western and central Contra Costa and Alameda counties (California) which is now fragmented into five populations (US Fish and Wildlife Service 1997).[7]

The Alameda whipsnake population has been fragmented into five mostly isolated subpopulations whose numbers are unknown, but which are certain to be rapidly declining as suitable habitat is lost to urban development. Little population abundance data exists for the Alameda whipsnake. Almost all trapping studies targeting this species have been designed to determine presence or absence for regulatory purposes and assessing impacts to potential habitat. As such, monitoring is most often habitat based; assuming snake abundance is positively correlated with the amount of coastal scrub or chaparral vegetation and rock lands present.

The Alameda whipsnake is non-migratory, so distribution is not large. The current distribution has been fragmented into five populations; the Tilden-Briones, Oakland-Las Trampas, and Mount Diablo-Black Hills populations in Contra Costa County, the Hayward-Pleasanton Ridge population in Alameda County, and the Sunol-Cedar Mountain population largely in Alameda County with extensions into San Joaquin and Santa Clara Counties, with little to no interaction between the populations. It is estimated that the snakes go no more than 1 mile away from core coastal shrub habitat.

This species inhabits a variety of different chaparral, which includes vegetation composed of broad-leaved evergreen shrubs, bushes, and small trees usually less than 2.5 m. The cover is typically dense and dry during the striped racer's peak activity. Although this is where they reside, they forage in other communities in the inner Coast Range, like grasslands, pond and stream edges, and woodlands. Rock outcrops are favorable whipsnake habitats as well, as they provide dens, refuge for predators, and cool areas to escape from excessive heat. Whipsnake prey is also abundant in rocky outcrops, giving the snake plenty of foraging opportunity. The habitat must be a good mix of sunny and shady sites, partially open shrubland, and foraging sites for the whipsnake to meet its biological needs.

The Alameda whipsnake was first listed as a threatened species under the California Endangered Species Act in 1971 and the US Endangered Species Act listed it in 1997. The first 5-year review was established in 2011 and recommended no change from current listing. 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 themselves 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.[2][8]