Recovery of a threatened seabird after eradication of an introduced predator: Eight years of progress for Scripps’s murrelet at Anacapa Island, California

Nocturnal Spotlight Surveys for Monitoring Scripps's Murrelets in At-Sea Congregations at Anacapa Island, California

“…NEST SEARCHES.-Small handheld flashlights were used to search suitable crevices and other sheltered sites for evidence of past or current breeding (e.g., incubating or brooding adult; whole, unattended eggs; broken or hatched eggshell fragments; eggshell membranes; or chicks; Whitworth et al 2005Whitworth et al , 2013. All nest search areas were accessed by an inflatable boat.…”

“…Only 2 of the 4 nests found in 2012 were also active in 2013. Overall, 6 of 8 clutches (75%) with known fates were successful (defined as at least one hatched egg per clutch; Whitworth et al 2013). We did not determine the clutch fate for nest 3 where an incubating adult was observed in April 2012 (Fig.…”

“…Obtaining an adequate sample of monitored nests to determine hatching success and to assess reasons for clutch failures (e.g., Whitworth et al 2005Whitworth et al , 2013) is another important step in protecting and restoring Scripps's Murrelets at Catalina. Under typical weather conditions, nest searches and monitoring can be conducted every 10-14 days on the protected and easily accessible shorelines adjacent to the Isthmus Cove and Twin Rocks congregations, and possibly east of Whale Rock near the Northwest congregation.…”

“…Under typical weather conditions, nest searches and monitoring can be conducted every 10-14 days on the protected and easily accessible shorelines adjacent to the Isthmus Cove and Twin Rocks congregations, and possibly east of Whale Rock near the Northwest congregation. This interval between nest checks is efficient for monitoring at islands such as Catalina, as it allows for reliable estimation of hatching success and timing of breeding and reasonable detection of clutches depredated soon after egg laying (Whitworth et al 2013).…”

“…Deer mice are known predators and scavengers of murrelet eggs at Santa Barbara Island and Anacapa Island (Schwemm and Martin 2005). Scavenging of unviable abandoned eggs by deer mice can be difficult to separate from egg predation, which typically occurs when viable eggs are left unattended by adults (Drost and Lewis 1995, Schwemm and Martin 2005, Whitworth et al 2013.…”