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r / Nn � V% behavior "placid," to the extent that their behavior is used as a secondary criterion for characterizing them to the species level. Salt marsh harvest mice are quite buoyant because their fur does not get saturated quickly, and they are good swimmers and climbers (Cal/EPA DPR online). During the highest water tides, they move into higher grasslands (Veloz 2003) They are prunarily nocturnal, but under laboratory conditions, they have been observed to be active at twilight or before sunrise (Cal/EPA DPR online). R r. raviventri.r can become torpid, especially in the early morning; neither the northern subspecies nor the closely related westem harvest mouse exhibits this behavior (CDFG on line) They are active all year round (Cal/EPA DPR online). Ecological threats The 1984 USFWS Recovery Plan listed the principal reasons for the decline of the salt marsh harvest mouse: habitat loss, fragmentation of remaining marshes, widespread loss of the high marsh zone through backfilling, land subsidence, and changes in vegetation. Over the long term, the mice may be threatenedby a sea level rise as great as 1.2 meters predicted to occur within the next 100 years, which could result in a permanent decrease in marsh habitat. In addition, upstream water diversions and/or dams reduce sediment supply per habitat by 45 percent, according to one estimate (DWR IEP). Changes in water salinity, which impact the saline vegetation that is prunary habitat for the mouse. Additionally predators contribute to the decline of the mouse. Dilution ofsalt watet. San Jose's sewage treatment plant pumps about 120 million gallons per da3• of treated water into San Francisco Bay near Alviso, which can dilute the salt content of the marshes, ultimately changing marsh ecology. The salt water tums brackish, causing some plants and anunals to die off, including pickleweed, a necessity for salt marsh harvest mice (Rendon 1999). Ptedatots. With development around the Bay margin, access to salt marsh harvest mice b�� predators such as feral and house cats and red foxes has become easier. Native predators include hawks, owls, heron, and clapper rails (Shellhammer, 1998). Other predators include egrets and night herons (Cal/EPA DPR online). Mammalian Predators Trapped at Redwood Shores Peninsula, May 22, 2000 — December 31, 2003 Inclusive Dates Number 8 Type of Disposition of Predators (following Predators Tra ed trans ort to PHS * 12 feral cats (Feli.r 2 cats returned to owners, 3 cats adopted, 5 FY 2000 (October 1, dome.rticu.r), 4 raccoons cats euthanized, 1 pending at time of report, 1 1999 — September 30, �Procyon lotar), & i striped escaped; 3 raccoons & 1 skunk microchipped 2000) skunk (Mephiti.r mephiti,r). and released w/in 3 miles of capture site per CDFG oli ; 1 raccoon euthanized. 1 cat returned to o�vner, 3 cats adopted, 1 FY 2001 (October 1, injured cat euthanized; 1 raccoon euthanized, 3000 — September 30, 6 feral cats, 2 raccoons. as it had been captured the preceding year; 1 2001) raccoon microchipped and released w/in 3 miles of ca ture site er CDFG oli � 12