Encompassing a large region of coastal bottomlands midway between Santa Cruz and Monterey, the Elkhorn Slough ecosystem is one of the richest estuaries in the state. It is designated a National Estuarine Research Reserve (one of three in the state). It includes the main slough channel through tidal marshes, the abandoned salt evaporation ponds near the mouth of the channel, as well as myriad side channels, potholes, feeder streams, and regularly-flooded pastures. These wetlands are surrounded by low hills with dense oak woodland and chaparral, with scattered riparian thickets and grassland. The bulk of the wetlands of Elkhorn Slough (c. 1000 acres) are well protected as federal and state conservation reserves (Elkhorn Slough Preserve/Elkhorn Slough Ecological Reserve, resp.).

Updated by Monterey Peninsula Audubon, August 2008

Ornithological Summary

The Elkhorn Slough region, which includes associated agricultural fields and pastureland, is a critical wintering and stopover site for shorebirds along the Pacific Flyway - any damp spot in the area can be filled with shorebirds during fall migration, and numbers have exceeded 30,000 individuals (Page and Shuford 2000). Though breeding populations of California Clapper Rail and Short-eared Owl have been extirpated, other sensitive marsh birds persist in strong numbers, including resident Savannah Sparrow, nesting ducks (incl. Gadwall, Northern Pintail, Northern Shoveler), Northern Harrier and American Bittern (scarce). Massive numbers of Tricolored Blackbirds have been observed wintering at Moonglow Dairy and have also bred occasionally in recent years (B. Sullivan via email). The large salt flats at Moss Landing are unique in the Monterey Bay area, and support breeding Snowy Plover. Both Caspian and Forster's terns have bred recently. Re-colonization by Least Tern and colonization by Black Skimmer as nesters is also possible (DR). Around 300 species of birds have been recorded here, and unlike migrant traps with similar totals, one can see over 100 on nearly any day of the year, making it among the most species-rich sites for birds in the state.

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Conservation Issues

Red Fox continues to pose a grave threat to Snowy Plover and other ground-nesting birds. Though the protected portions of Elkhorn Slough will probably remain free from development, the upland areas, including oak woodland, are currently under major threat from suburban sprawl associated with the Hwy. 101 corridor. During the 1990s, Audubon California was involved in a major planning effort for the Elkhorn Slough watershed to develop solutions for these concerns. If urbanization is not contained, conservationists anticipate increased problems with exotic species, including invasive plants and feral dogs and cats that prey upon ground-dwelling birds, and pollution from urban runoff.

Ownership

The bulk of the wetlands of Elkhorn Slough (c. 1000 acres) are well protected as federal and state conservation reserves (Elkhorn Slough Preserve/Elkhorn Slough Ecological Reserve, resp.).

Habitat

The Elkhorn Slough ecosystem is one of the richest estuaries in the state. It is designated a National Estuarine Research Reserve (one of three in the state). It includes the main slough channel through tidal marshes, the abandoned salt evaporation ponds near the mouth of the channel, as well as myriad side channels, potholes, feeder streams, and regularly-flooded pastures. These wetlands are surrounded by low hills with dense oak woodland and chaparral, with scattered riparian thickets and grassland.