Washington State Snowy Plover Population Monitoring, Research, and Management: 2011 Nesting Season Research Progress Report

During the 2011 Western Snowy Plover (Charadrius nivosus nivosus) nesting season, we monitored breeding phenology, nest success, fledging success and number of nesting adult plovers in Washington. Field monitoring and research was conducted by Wendy Pearson, Cyndie Sundstrom, and William Ritchie, with assistance from Marie Fernandez, Warren Michaelis, Scott Harris, Scott Pearson, and Steve Spencer. A summary of some of our 2011 activities and results:

Breeding Phenology

• Clutches were initiated between 21 April and 20 July (Figure 3). However, very early nests could have gone undetected because intensive surveys did not start until late March on Midway Beach and there was little coverage of Leadbetter until late June.
• The first chick known to fledged around 23 July and the last chick known to fledge, fledged around 9 September

Breeding Range

• Conducted 31 surveys on 12 sites to either assess occupancy or to count the number of nesting adults
• Snowy Plovers were only found nesting on Leadbetter Point and Midway Beach.

Number of Breeding Adults

• The mean 2011 Washington breeding adult population was 40 (95% Confidence interval: 20-60). All of the breeding adults observed were found on Leadbetter Point and Midway/Grayland Beach. Staff and volunteer surveyors conducted surveys.
• The Washington population is declining by approximately 4 birds per year over the past six years (p = 0.042), and has declined from four nesting sites to two over the past 6 years.

Nest success

• Thirty nests were discovered and monitored (fewer than in past years as a result of less effort in the spring at Leadbetter Pt.).
• The percent of nests that survived from egg laying through hatching during the 2011 nesting season was 28% (including exclosed and non-exclosed nests).
• As in past years, the primary source of nest failure was predation. Common Ravens and coyotes were the only identified nest predators. However, in many cases we could not identify the nest predator.

Fledging Success

• The average number of young fledged per adult male on the two nesting sites in Washington was 1.70 (95% Confidence interval: 0.90-2.70). Population viability analyses indicate that at least one young must fledge per adult male on average to have a stable population.

Management Actions

• Restrictions: Beaches were closed to fireworks at locations where State Parks and U.S. Fish and Wildlife Service are the upland land owners.
• Nest exclosures: Three nests were exclosed on State Park land at Midway Beach.
• Signing: Approximately 7.5 miles of beach was signed at Leadbetter and approximately 1 mile of Midway Beach was signed to restrict human access to the dry portion of the beach and protect nests. Access restrictions did not occur on private land.
• Nest Predation: Willapa National Wildlife Refuge continued conducting surveys to collect data on nest predators occurring in and adjacent to the plover and lark nesting areas at Leadbetter Point. Logistics of implementing a proposed predator management strategy were investigated.
• Restoration: The U.S. Fish and Wildlife Service habitat restoration area (HRA) at Leadbetter Point is 121 acres, of which oyster shell has been added to approximately 62 of the 121 acres. There was no enlargement of HRA in 2011 and no aerial herbicide spray. Maintenance non-native beachgrass control included hand spraying in the south central portion of the HRA. Harrowing to redistribute shell in the north end of the shelled area of the HRA and bulldozing to remove beachgrass and widen the dune cuts in the swale adjacent to the west edge of the south HRA was conducted in February.
• No habitat restoration work was conducted on State Parks lands at Leadbetter Point or Midway Beach in 2011.

Recommendations

• Summarize, write-up and publish population monitoring results from Oregon, Washington, and northern California.
• Continue to examine the effectiveness of habitat restoration areas.
• Identify the conditions where plover populations are more likely to be self-sustaining.
• Conduct research to identify habitat features important to successful plover nesting.
• Begin implementation of a predator control plan for active snowy plover nesting locations. Continue to engage volunteers in monitoring.
• Continue to link management activities with research and monitoring.
• Continue to evaluate the effectiveness and continued use of nest exclosures on an annual basis.
• Evaluate impact and timing of clam digging on plover nesting, foraging and fledging.
• Initiate education and outreach activities.