This complex of habitats includes a tidal slough and river mouth lagoon (seasonally brackish), salt marsh, sandy beach, coastal scrub, and groves of eucalyptus and cypress. It is the most productive river mouth setting in the county, and a key area for finding waterbirds. The configuration of the river mouth and its lagoon changes continually over time with river conditions. Most of the lagoon and the site where the river usually meets the sea lie in Monterey County, but the northern margin of the lagoon is in Santa Cruz. Two private developments at Pajaro Dunes limit access, but courteous birders usually may explore most of the area.
Directions. Take the Riverside Dr (Hwy 129) exit west off Hwy 1. Riverside Dr quickly turns right toward its intersection with West Beach Rd. Turn left (west) on West Beach Rd and drive 2.8 miles to its end. Just before its end, the road crosses Watsonville Slough (check from the road for waterbirds). Park at the end of West Beach Rd or in the adjacent lot for the Palm Beach Unit of Sunset State Beach. The trees and shrubs at the end of the road have had rarities in fall and winter. From the end of West Beach Rd one can explore the grove of trees, and walk over the dunes to the beach and bay (lighting and winds best early in the morning). The mouth of the Pajaro R is a one-mile walk south along the beach. You may obtain permission to access the Pajaro Dunes complex, see this page: Pajaro Dunes Access. If access is granted one can politely request entry at the visitor’s entrance of the “Pajaro Dunes” development, and ask to drive to the river mouth to view the birds. Please be courteous and patient with the development’s staff and residents, so that future birders will be welcome. Drive in and check adjacent Watsonville Slough and any flooded lawns along the way. Park at the end of the road at “Pelican Point” and walk on a prominent boardwalk between the condominium buildings closest to the river to view the river mouth and lagoon.
Returning from the river mouth or beach to West Beach Rd, drive back east a mere 0.2 mile and turn left on Shell Rd. Check Watsonville Slough at the Shell Rd crossing (0.2 mile), then continue a short distance and park on the right off the pavement, outside the entrance to the “Shorebirds” development. Shorebirds Pond (brackish) is just inside the entrance, with a paved loop trail around it. The path skirting the pond’s north side is a public pathway leading to Sunset State Beach (see the next site description), but one must get permission at the visitor’s entrance to walk the loop around the pond.
Birds. The beach at Pajaro Dunes has various gulls and the expected sandy beach shorebirds. American Pipits are common in late fall and winter, and watch for rarities (Scissor-tailed Flycatcher and an apparent White Wagtail have appeared). Seasonally the full range of loons, grebes, scoters, terns, and others swim just off the beach. Brown Pelican and Elegant Tern are numerous in summer and early fall, when Parasitic and Pomarine jaegers occur regularly. Huge flocks of Sooty Shearwaters fly by late on summer afternoons. Snowy Plover is resident on the beach; be sure to respect any seasonal closures of parts of the beach to protect them.
Many rarities have turned up among the large flocks of Brown Pelican and various terns, gulls, and shorebirds that roost here during the day. Shorebird diversity at the river mouth is usually good, especially from August through October. This is one of the best areas in the county for American Avocet, Long-billed Curlew, and Dunlin. All the locally wintering gulls occur here, including Glaucous (rare but regular), Thayer’s (often in double digits), and Black-legged Kittiwake (rare). There are several records of Franklin’s Gull, and a few even of Laughing Gull. Hundreds of Caspian and Forster’s terns gather in spring and over a thousand Elegant Terns may be seen on some summer and early fall days. Common Tern is regular in late spring and fall; rare terns have included Royal, Least, and Black. Black Skimmers appear occasionally, especially from May to August. Osprey, Peregrine Falcon, and Merlin visit frequently. Ducks use the river lagoon. There are often many wintering Bufflehead, Common Goldeneye, and both scaup here. This is one of the best spots to find Greater Scaup, and Long-tailed Duck drops in sporadically. Red-breasted Merganser, and Horned, Eared, Western, and Clark’s grebes are regular. Migrating Brant appear in small numbers, and occasionally stay into summer.
Visitors at Watsonville Slough include many of the ducks that visit the river mouth lagoon, including Blue-winged Teal in fall and winter. Check the margins of the slough and any flooded lawns for stilts, avocets, peeps, both yellowlegs, both dowitchers, Red-necked Phalarope, and herons and egrets.
One or two wintering wild geese often join the domestic flock at Shorebirds Pond. Several shorebird species usually reward the birder here, including Red-necked Phalarope and an occasional Wilson’s in the fall. The pond attracts both dabbling and diving ducks. During fall and winter, House Wren and Blue-gray Gnatcatcher live on the scrub slope east of the pond, and California Thrasher is resident there. Look for Common Yellowthroat and various sparrows in the scrub flat on the northeast side of the pond.
The grove of eucalyptus and cypresses at the end of West Beach Rd and around the Palm Beach Unit parking lot merits careful attention during migrations and in winter, when a variety of rare landbirds have been found (e.g., Gray Catbird, Prothonotary, black-throated Blue and Virginia’s warblers, Summer Tanager). Allen’s Hummingbird nests here, and Great Horned Owl is resident.