AgdaPkt 2004-09-13 - Laserfiche WebLink

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��+;� traffic in conformance with the recommendations of the Bay Trail Comnuttee for San Francisco Bay access and transportation. The U.S. Army Corps of Engineers (Corps) determined that a levee height increase was necessary to protect the existing Redwood shores development from inter-tidal San Francisco Bay inundation. The Corps, as the designated action agency on the project, detemuned that the levee height increase "may affect" the habitat of the California clapper ra.il and the salt marsh harvest mouse pursuant to the Endangered Species Act (ESA or "the Act"). The Corps sought informal consultation with the U.S. Fish and Wildlife Service (FWS) under Secrion 7 of the ESA. At issue was the protection of endangered California clapper rails and the salt marsh harvest mouse on Bird Island which lies off of the shores of Redwood Shores. Bird Island is a salt marsh habitat for clapper rails. During a period of high tide, the ra.il seeks refuge in elevations above high tide. The rail forages on Bird Island but nests on pickleweed, a native plant, elevated on a platform of stems without a canopy. The fear of the FWS was that as a result of the ra.ised elevations of the levees there would be less usable habitat available for refugia. Without sufficient institutional controls one of the main predators of the clapper rail, domestic pets, would be able to access and exrirpate the rails foraging on Bird Island. t�fter a period of failed negotiations with the City, all pedestrian access to the levee tra.il at the eastern border of Redwood Shores was prohibited as a condition of a biological opinion issued by the FWS to the Corps. No similar restrictions had been placed on any California clapper habitat in the past and no such restriction has been instituted since. The California clapper rail was reclassified as a geographically d.istinct species in 1880. The clapper rail (Rallu.r obsoletu.r) is one of the largest species of the genus that extends to South America. The ra.il has a hen-like appearance, strong legs with long toes, a long slighdy decurved bill, and white undertail feathers. Rails typically occur in salt water marshes dominated by pickelweed and cordgrass. Loss of habitat throughout its salt marsh range is the main factor in the reduction in the number of Califorrua clapper rails. The ra.il is secretive, but once flushed, can be approached easily. They are described as tolerant of human beings. Rails consume the introduced horse mussel, spiders, clams, and yellow shore crabs. With a stabilizing habitat picture, the main factor in mortality is predation. The recovery plan for the California clapper rail states that, "(A)dult clapper rails are taken by several avian predators including the northern harrier, red-tailed hawk and peregrine falcon. Downey young and eggs are also vulnerable to predation by Norway rats." The salt marsh harvest mouse (Reithrodontomy.r raviventri.r) is a small native rodent found in the marshes of Corte Madera, Richmond and South San Francisco Bay. Salt marsh harvest mice are critically dependent on dense cover and their preferred 20