Delta & Lodi Area
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Description of the Area
This site is technically known as the White Slough Wastewater Treatment Plant, but it should not be confused with the nearby White Slough Wildlife Area. During those times of the year when hunting is allowed at the Wildlife Area, birds seek refuge at the ponds in the sewage treatment plant. While not nearly as accommodating as in the past, this WTP continues to allow birding with certain restrictions. It is technically open to birding only on weekdays during regular office hours, but the gate is frequently open on weekends. After signing in at the office, park in the clearly designated birder parking area. Your visit to the ponds is restricted to walking only.
How to Get There
Take I-5 to the Lodi area, and exit at Hwy 12. going east. Turn right at Thornton Rd (south), and travel about 1 mile to the first right turn, and drive under the overpass of I-5. Just beyond the overpass, make the first left into the fenced area and follow the road to the sewage plant office to sign in (required).
Target Birds
Year-round: Pied-billed Grebe, Great Blue Heron, Great Egret, Gadwall, White-tailed Kite, Red-shouldered and Red-tailed hawks, Black-necked Stilt, House Finch.
Spring/Summer: Swainson’s Hawk, American Avocet, Wilson’s Snipe, Tree, Northern Rough-winged, Cliff, and Barn swallows.
Winter: Horned and Eared grebes, Double-crested Cormorant, American Wigeon, Cinnamon Teal, Northern Shoveler, Green-winged Teal, Canvasback, Ring-necked Duck, Greater (rare) and Lesser scaups, Bufflehead, Common and Barrow’s (rare) goldeneyes, Black-bellied and Pacific Golden-plovers, American Avocet, Greater Yellowlegs, Spotted, Western, and Least sandpipers, Dunlin, Long-billed Dowitcher, American Pipit. Less common are American Kestrel, Merlin, Peregrine Falcon, Lesser Yellowlegs, Franklin’s (rare) and Bonaparte’s gulls, Forster’s Tern.
Migrant: Pacific Golden-Plover, Semipalmated Plover, Lesser Yellowlegs, Baird’s and Pectoral sandpipers, Short-billed Dowitcher, Wilson’s Phalarope, Caspian and Black terns, Bank Swallow.
Rarities: Brown Pelican, White-winged Scoter, Long-tailed Duck, Hooded Merganser, Snowy Plover, Marbled Godwit, Red Phalarope, Laughing, Franklin’s, and Sabine’s gulls, Least Tern, Solitary and Semipalmated sandpipers, Willet, and practically any shorebird. It is best to check these ponds immediately after a storm to see if anything has blown in.
EBird Hotspot Information
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Birding At the Site
While driving along Thornton Rd, look at the fields to the east for Cattle Egrets, Long-billed Curlews, Whimbrels, Black-bellied Plovers, and other shorebirds. Be sure to check overhead for hawks. In the winter, Ferruginous Hawks are occasionally seen on the ground along Thornton Rd, approximately 1 mile south of the turn-off to the plant. Red-tailed Hawks are often found on the telephone poles along the route to the plant. Turning into the plant takes you along the east side of the ponds. Check the fenced-in grassy area for House Finches and Brown-headed Cowbirds. An American Kestrel is often seen sitting on the post just north of the ponds feasting on an unlucky passerine.
Visitors in the past were able to drive in and use their vehicles as a blind. Since this is no longer an option, proceed on foot carefully to reduce the likelihood of spooking the birds. You will often find domestic ducks here, but look closely along the edges for Spotted Sandpiper, especially in winter. A Red Phalarope was seen here Thanksgiving weekend 1997 and the winter of 1998. The level of water changes in the ponds. Sometimes the large ponds are full, leaving no habitat for shorebirds. When this occurs, be sure to look in the two small ponds at the south end of the complex, as there is often some habitat remaining.
The route you take around the ponds is your choice. Take the route that gives you the best exposure, depending on the angle of the sun. Look for Wilson’s Snipe. Check the field on the west side of the ponds for Cattle Egret in winter, Blue Grosbeak in summer, White-faced Ibis, White-tailed Kite, Red-tailed Hawk, and Merlin in winter. Peregrine Falcon and Bald Eagle have been seen in winter, so keep your eyes peeled. When the swallow flocks form in late summer, check them for an occasional Bank Swallow.
More Information
Timing:
Parking: Parking available.
Facilities: There are restrooms at the office; ask for permission there. Otherwise, the nearest restrooms are along Thornton Rd near Hwy 12 at any of the service stations or restaurants.
Accessibility: A paved trail
Dogs: Not Allowed
Bikes: Not Allowed
Others: