Washington State Snowy Plover Population Monitoring, Research, and Management: 2013 Nesting Season Research Progress Report

During the 2013 Western Snowy Plover (Charadrius nivosus nivosus) nesting season, we monitored breeding phenology, nest success, fledging success and number of nesting adult Snowy Plovers in Washington. Field monitoring and research was conducted by Cyndie Sundstrom and William Ritchie with assistance from Brock Hoenes, Ken Scheffler, Warren Michaelis, Steve Spencer, and Larissa Pfleeger. Management activities included restricting human access to nesting sites, exclosing nests to prevent predation, predator management, and restoring nesting habitat. A summary of some of our 2013 activities and results:

Breeding Phenology

• Clutches were initiated between 12 April and 20 July (Figure 2). However, very early nests could have gone undetected because intensive surveys did not start until late March on Midway Beach and early April at Leadbetter Point.
• The first chick known to have fledged, fledged around 24 June and the last chick known to fledge, fledged around 9 September.

Breeding Range

• We conducted 20 surveys at 9 sites between 16 May and 26 July 2013 to either assess occupancy or to count the number of adults.
• Snowy Plovers were only found nesting on Leadbetter Point, Midway Beach, and Graveyard Spit.

Number of Breeding Adults

• The mean 2013 Washington breeding adult population was 43 (Range: 41-45). All of the breeding adults observed were found on Leadbetter Point, Midway Beach, and Graveyard Spit. Staff and volunteer surveyors conducted surveys.
• From 2006-2009 the Washington Snowy Plover population declined annually and precipitously. From 2009-2012, the adult breeding population has been fairly stable around 31-36 birds. There is some suggestion of an increase in 2013 relative to the recent lows but several more years of monitoring will be needed to assess whether or not trends are indeed changing.

Nest success

• Twenty-nine nests were discovered and monitored. The lower number of nests discovered in part reflects less effort focused on nest monitoring at Leadbetter Point than in past years. Based on chicks we observed on the beach, we know there were at least 6 additional nests that we did not locate. The lower number of nests may also reflect fewer re-nesting attempts due to reduced predation pressure as a result of predator management.
• The percent of nests that survived from egg laying through hatching during the 2013 nesting season was approximately 50% (includes exclosed and non-exclosed nests) which is extremely unusual. The nest success at Leadbetter Point (the site with the lowest nest success in past years) was extraordinarily high, with 79% nest success. This was the first year that predator management was implemented in Washington and it was only implemented at Leadbetter Point.
• For the first time, nest predation was not the primary source of nest failure. Common ravens were the only identified nest predator and were identified based on tracks left at the nest. However, in several cases we could not identify the nest predator.

Fledging Success

• The average number of young fledged per adult male on the three nesting sites in Washington was 1.04 (range = 0.92-1.18). Population viability analyses indicate that, on average, at least one young must fledge per adult male to have a stable population.

Management Actions

• Restrictions: Fireworks were prohibited on beaches where State Parks and U.S. Fish and Wildlife Service (USFWS) are the upland land owners.
• Nest exclosures: Two nests were exclosed on State Park land at Midway Beach and no nests were exclosed at Leadbetter Point.
• Signing: In an effort to protect nests, approximately 7.5 miles of beach at Leadbetter Point and approximately 1 mile of beach at Midway Beach was signed to restrict human access on the dry portions of the beach. Access restrictions on private land only occurred when permitted by the land owner.
• Nest Predation: The Willapa National Wildlife Refuge (Willapa NWR) continued to collect data on nest predators that occurred in and adjacent to areas where Snowy Plovers and Streaked Horned Larks nest at Leadbetter Point. Hazing and lethal removal of known nest predators (corvids) observed foraging in active Snowy Plover nesting areas was initiated in 2013 at Leadbetter Point.
• Restoration: The Willapa NWR habitat restoration area (HRA) at Leadbetter Point now totals more than 300 acres. This area was mostly cleared of non-native beachgrass using mechanical and chemical methods. In addition, oyster shell was spread across about 62 acres of the HRA to both attract Snowy Plover nesting and to help stabilize drifting sand. In 2013, treatments within and adjacent to the HRA included using a bulldozer and a tractor-mounted disk to remove dead and resprouting beachgrass and using a helicopter to apply herbicide to kill beachgrass.
• No habitat restoration work was conducted on State Parks lands at Leadbetter Point or Midway Beach in 2013.