Snowy plover monitoring protocol for Point Reyes National Seashore: Version 7.1.

Adams, Dawn; Koenen, Marcus; Peterlein, Kate; Press, David; Allen, Sarah

Western snowy plovers were listed as threatened by the United States Fish and Wildlife Service in 1993 (USFWS 1993). These small birds breed regularly at Point Reyes National Seashore (PORE) and a population also inhabits its beaches during the non-breeding season. This protocol documents the sampling design, field methods, analytical techniques, reporting requirements and budget required to monitor breeding plovers annually at PORE. The methods have remained largely unchanged since monitoring began at PORE by PRBO Conservation Science (PRBO) and the national seashore staff since the 1970s. The monitoring objective is to determine the trends in the estimated breeding population size, distribution, and reproductive success of snowy plovers at known breeding beaches at Point Reyes National Seashore. The number and length of survey areas beaches and annual average number of nests is small enough that it is possible to do a complete census of the nesting population twice a week during the breeding season (March through September). Nest visits every few days are used to track the fate of nests, eggs, and chicks. During surveys, predators seen are identified within survey areas. Every known, historic snowy plover breeding beach within PORE is surveyed for breeding adults. There are six survey areas: four on Point Reyes Beach, one on Limantour Spit, and one on Drake’s Spit. Currently at PORE, snowy plovers nest in two of the six survey areas, both on Point Reyes Beach: Kehoe Beach (K) and a section of Point Reyes Beach between Abbott’s Lagoon and the North Beach parking lot (NP). In the past, nesting has occurred within Drake’s Bay at Drake’s Spit (D) and Limantour Spit (L) and additional appropriate habitat is at North Beach (NB) and South Beach (SB). Annual breeding population sizes range from a high of 50 in 1987 to a low of 10 in 1996. Fledged chicks per egg values (number of fledged chicks per egg) ranged from 0.01 in 1989 to 0.58 in 1996 and 1998. Nest failures have been largely attributed to predators and predator exclosures have been used by the park as a management tool since 1996. Beach visitors especially those with unleashed dogs have sometimes presented a threat to the ground nesting birds. In response, the park established a snowy plover docent program in 2001 to educate beach visitors about the nesting snowy plovers and beach recreation restrictions. Collection of presence/absence and abundance information of the number of human, pet dogs (leashed and unleashed), and potential snowy plover predators is important to park managers and the data are collected during snowy plover census and nest check surveys. It is recognized that because these data are not currently collected with systematic, standardized sample efforts, the relationship between ancillary data collected on predator populations and plover population trends cannot be determined with statistical estimates of certainty. Results from an ongoing diurnal predator abundance pilot study will be used to revise predator survey methods, data collection, and correlation analyses. In addition, a snowy plover, long-term trend report is due to be completed in 2014 which will further inform future protocol revisions.

Snowy plover monitoring protocol for Point Reyes National Seashore: Version 7.1.

Series

Collections