Population monitoring of endangered light-footed clapper tails (Rallus longirostris levipes) from Carpinteria Marsh in Santa Barbara County to Tijuana Marsh in San Diego County, California was conducted from 1980 to 1991. Annual spring call counts ranged from 277 pairs in 19 marshes in 1984, to 142 pairs in 14 marshes in 1985. In 1991,235 pairs were detected in 11 marshes. The historic northern subpopulation in Carpinteria Marsh had been extirpated, and up to 71% of the entire U.S. population was concentrated in one marsh, Upper Newport Bay, Orange County. Nesting rafts were provided at the Seal Beach National Wildlife Refuge (SBNWR) beginning in 1987 and by 1991 the 60 rafts available held 37 nests and 30 clutches of eggs with an overall hatching success of72%. Red foxes (Vulpes vulpes), were problematic non-native predators of clapper tails and were trapped, beginning in 1986 and through 1989,275 foxes were removed from the SBNWR and surrounding 4,000 acres. From 6 breeding pairs in 1989, the clapper tail population at Seal Beach increased to 28 pairs by the spring of 1991. A post?breeding high tide count in November, 1991 revealed a minimum of 98 clapper tails, the highest count ever recorded in this marsh.
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