California Least Tern & Western Snowy Plover (Oceano Dunes SVRA)

Oceano Dunes SVRA, a popular OHV park with approximately 1.9 million visitors per year, is an important breeding site for two special-status ground nesting birds—the state and federally endangered California least tern and the federally threatened western snowy plover. The snowy plover population at the Park is comprised partly of resident birds, present year-round, and partly of migrant birds, present only during the breeding or wintering season. There is intensive monitoring of the nesting birds by Park staff and contractors. Management efforts include:

• maintaining an approximate 300-acre fenced exclosure seasonally from March to October,
• extensive seasonal habitat enhancement,
• color banding of all chicks,
• predator management,
• educating Park visitors, and
• enforcement of resource protection regulations.

These efforts help in the recovery of the least tern and snowy plover while keeping OHV use and other recreational opportunities available to the public.

California Least Tern Breeding Statistics
In 2008, the Park had a minimum of 55 least tern breeding pairs. This is the highest documented number of breeding least terns at Oceano Dunes SVRA compared to a range of 31-54 during the 2003-2007 period. The nest hatch rate for 2008 was 89% and the chick fledging rate was 71% (70 of 90 chicks) with 1.27 chicks fledged per pair. For all least tern colonies in California, the average number of fledglings per pair was much lower with a range of 0.33-0.39 in 2007 (Marschalek 2007).

Western Snowy Plover Breeding Statistics
The Park had a minimum of 95 breeding snowy plovers in 2008 compared to 79 in 2007. There were 121 known nesting attempts, a 68% nest hatching rate, and a chick fledgling rate of 37% (72 of 197 chicks). One chick fledged per breeding male is the estimated number needed to prevent the population from declining (US Fish & Wildlife Service 2007). In 2008, an estimated 1.33 juveniles fledged per male at Oceano Dunes SVRA. For the six-year period 2002-2008, average productivity was 1.32 fledged chicks per breeding male.

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Marschalek, D.A., 2007. California Least Tern Breeding Survey, 2005 season. California Department of Fish & Game, Sacramento, CA.

USFWS, 2007. Recovery Plan for the Pacific Coast Population of the Western Snowy Plover (Charadrius alexandrinus nivosus). In two volumes. Sacramento, CA. xiv+751pp.