Washington State Snowy Plover Population Monitoring, Research, and Management: 2018 Nesting Season Research Progress Report

During the 2018 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, William Ritchie, Larissa Ritzman, and Richard Ashley, with assistance from Warren Michaelis. Management activities included restricting human access to nesting sites, predator management, and restoring nesting habitat. A summary of some of our 2018 activities and results:

Breeding Phenology 

• Clutches were initiated between 23April and 14 July, 2018 (Figure 2). However, very early nests may have gone undiscovered because nest searching did not start until early April.
• The first chick known to fledge, fledged around 13 June and the last chick fledged around 9 September.

Breeding Range

• We conducted 23 surveys at 10 sites between 21 May and 22 June, 2018 to either assess site occupancy status or to count the total number of adults.
• Snowy plovers were found nesting on Leadbetter Point, Midway Beach, and Graveyard Spit.

Number of Breeding Adults 

• The mean 2018 Washington breeding adult population was 87 (Range: 80-91). Breeding adults were observed on Leadbetter Point, Midway Beach, Graveyard Spit, and we also observed at least one plover pair on the outer beach between Ocean Shores and Connor Creek, although a nest was never discovered, so breeding at this location was not confirmed.
• From 2006-2009 the Washington snowy plover population declined annually and precipitously.
• From 2009-2012, the adult breeding population was fairly stable at around 31-36 birds. Since 2013, the population has more than doubled

Nest success 

• Seventy-two nests were discovered and monitored at Midway Beach/Graveyard Spit, and Leadbetter Point. At least three nests went undiscovered because we observed broods on the beach that were not associated with known nests.
• Thirty-two (44%) of the 72 nests that we monitored hatched and most of the remaining nests were lost to predation.
• After a steady four-year decline in nest predation, predation by avian predators was once again the primary source of nest failure in 2018.

Fledging Success

• We estimated that 0.76 (0.65-0.93) chicks fledged/male on the three Washington nesting sites in 2018. A population viability analysis indicates that, on average, at least one young must fledge per adult male to have a stable population (Nur et al. 1999). The average number of chicks fledged per male was approximately 1.4 over the last five years.

Management Actions 

• Nest exclosures: No nests were exclosed in 2018.
• Signing: In an effort to protect nests from human activities, approximately 8.0 miles of beach at Leadbetter Point and approximately 1.3 miles of publicly owned (Washington State Parks Seashore Conservation Area) beach at Midway Beach were signed to restrict human access to critical nesting areas. Nearly 166 acres spanning just over-one mile of linear beach was also signed and roped at Graveyard Spit.
• Clam tides: Washington Department of Fish and Wildlife coordinated most law enforcement activities especially during clam tides. Additional enforcement activity was provided by Washington State Parks and US Fish and Wildlife Service.
  • Long Beach: During the snowy plover breeding season, only 2 days of razor clam digging occurred during the month of April compared to eleven days in 2017. Portable toilets were again placed on the beach at Leadbetter to minimize intrusions into the closed nesting habitat.
  • Midway Beach: Clam digging occurred on 2 days during the plover breeding season in April compared to 15 days of overlap in 2017.
  • Graveyard: tribal clam harvest was permitted in July.
• Nest Predation: Predator management was conducted by wildlife specialists with USDA APHIS Wildlife Services on both Leadbetter Point and Midway/Grayland Beach in 2018. In addition Graveyard Spit was visited twice. Predator management consisted of dispersing birds or performing targeted lethal removal of known nest and chick predators (corvids) in or adjacent to the plover nesting areas. Results suggest that this activity is successful in increasing nest hatching rates and fledging rates.
• Restoration:
  • Forty acres of beachgrass was cleared on the Long Beach Peninsula, 15 acres on the Willapa National Wildlife Refuge and 25 acres on State Park land.
  • An additional 90 acres previously cleared was also disked to reduce resprouting beachgrass.
• Outreach: Radio Advertising – A 60 second public service announcement to promote plover conservation was aired on local radio stations during Earth day weekend (April 21-22^nd) which coincided with recreational clam digging.
  • Midway Beach – 6% of recreational clam diggers reported hearing the announcement on April 21-22^nd
  • Long Beach – 13% of recreational clam diggers reported hearing the announcement on April 21^st