Thus its vulnerability, particularly in light of rapid land development taking place in the San Francisco Bay Area, was recognized by this group of researchers.

[1] Recently, two authors have advocated a reclassification for this subspecies of the checkerspot common to western North America, Euphydryas editha.

The eggs are deposited at the base of the dwarf plantain plant or less frequently the purple owl's clover or denseflower Indian paintbrush.

When the diapause ends they resume activity, feeding and move to complete their development into adult Bay checkerspot butterflies.

Some of these plants include California goldfields, white turtlehead, desert parsley, scytheleaf onion, false babystars, intermediate fiddleneck and others.

The populations of butterflies at Jasper Ridge had been the subject of intensive study and research at the lead of Stanford biologist Paul Ehrlich.

These satellites are typically generating very robust populations of Bay checkerspots in favorable weather with good habitat conditions.

It is one of two secondary larval host plants of the butterfly that remains edible later in the season and acts as a backup when the dwarf plantain dries up.

It prefers mesas, slopes and open areas in ponderosa pine forests and poppy fields at elevations from 1,500 to 4,500 feet (1,370 m).

The flowers bloom from March to May and are about 1.25 inches long (32 mm) and formed in dense spikes, they are magenta or purple on the lower corolla lips and have yellow or white tips.

Flowers are pink/purple to white/yellow with five petals with white lobes that form a yellow "beak" and "eyespots" on the lower lip, which resembles the face of an owl.

In a large metapopulation south of San Jose, removal of cattle from grasslands that the butterfly inhabited led to a significant decrease in the butterfly population because grazing leads to a net export of nitrogen as the cattle are removed for slaughter after eating the plants of the grasslands.

Any question about whether nitrogen emissions from cars traversing U.S. Route 101, 110,000 vehicles daily, is significant evaporates when faced with monitoring statistics from Weiss.

By contrast, pollution from power plants and vehicles drops only about four to five pounds of nitrogen per acre per year on the Jasper Ridge preserve.

Ehrlich and his colleagues accumulated more data - probably more than is known about any other invertebrate - about the fluctuations of the Bay checkerspot populations at Jasper Ridge.

Consequently, Stanford University has dispatched Ehrlich and others to conduct "longterm studies of the Bay checkerspot butterfly and feasibility of reintroduction".

The professors participating, one each from biology, history, soil science and law, are examining the issues in restoring any extinct species or lost habitat.

[13] Other goals of the Jasper Ridge study include analyzing the regulatory framework for endangered species and how changes might aid recovery of species, characterizing the genetics of research collections and possible donor populations and examining the historical changes in ownership, management and condition of the serpentine grasslands that the Bay checkerspot calls home.

Fish and Wildlife Service identified four core areas along Coyote Ridge that require attention as Bay checkerspot habitat.

[6][7] Right before the Bay checkerspot was federally listed the USFWS entered into an agreement with Waste Management of California, Inc. and also the city of San Jose.

With hundreds of acres of serpentine soils, thousands of Bay checkerspot butterflies occur within the unit, which is considered one of the centers of the subspecies' metapopulation in Santa Clara County.

The USFWS Recovery Plan for Serpentine Soils Species put a high priority for conservation of the butterfly and its habitat.

Though several hundred acres of serpentine soils occur within the unit and include nectaring and dispersal areas there are no public lands in San Felipe.

As compensation the developer, Shea Homes, in 1991, established a permanent 115-acre (0.47 km2) site for butterfly conservation in the Silver Creek Hills.

Shea Homes also deposited $100,000 into an account dedicated to regional conservation of the Bay checkerspot, money now managed by USFWS.

That year the San Mateo County Board of Supervisors closed the golf course issue when they adopted a resolution that designated Edgewood Park "a scenic natural area where outstanding features as well as significant wildlife habitats are preserved in their present state for the enjoyment, education and well-being of the public."

At the same time the county also modified their agreement with Midpeninsula Open Space District, adding a clause to prohibit golf course development and emphasize natural resource preservation and low intensity recreation.

This local extinction has been attributed to nitrogen deposition from cars traveling on adjacent Interstate 280, which fertilized invasive Italian ryegrass and choked out native plants required by the butterflies.

[15] Subsequently, attempts to restore the habitat by mowing at an appropriate time of year to reduce the Italian ryegrass and allow the native plants to regrow.

The permit for the plan expires on March 31, 2013, and there are currently no provisions in the HCP for incidental take of Bay checkerspots.