Washington State Snowy Plover Population Monitoring, Research, and Management: 2017 Nesting Season Research Progress Report

During the 2017 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, Alison Fox, Stephen Roethle, Larissa Ritzman, 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 2017 activities and results:

Breeding Phenology 

• Clutches were initiated between 27^th of March and 12 July (Figure 2). Note - very early nests could have gone undetected because intensive surveys did not start until early April.
• The first chick was known to have fledged around 14 June and the last chick fledged around 12 September.
• There was a late season peak in both clutch initiation and fledging.

Breeding Range 

• We conducted 22 surveys at 10 sites between 15 May and 23^rd of June 2017 to either assess site occupancy status or to count the number of adults.
• Snowy plovers were found nesting on Leadbetter Point, Midway Beach, and Graveyard Spit.

Number of Breeding Adults 

• The mean 2017 Washington breeding adult population was 78 (Range: 70-86). Breeding adults were observed on Leadbetter Point, Midway Beach, Graveyard Spit
• 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 

• Sixty-eight nests were discovered and monitored at Midway Beach/Graveyard Spit, and Leadbetter Point. At least four nests went undiscovered because we observed broods not associated with known nests. Another two nests were found after they were depredation.
  • Individual nests that are not observed more than once after discovery are removed our analysis of nesting success.
• The percent of nests that survived from egg laying through hatching during the 2017 nesting season was approximately 54% (74 total nests of which 39 hatched). When accounting for exposure, nest success was 64% (Mayfield Method). Wire cages have not been placed around nests to exclude predators (exclosures) since 2013. This extremely high nest success rate for unexclosed nests is likely attributable to USDA Wildlife Service's ongoing predator management on Leadbetter Point and Midway Beach.
• Wind-blown sand and human activities were the primary sources of nest failure. For the fourth consecutive year, nest predation was not the primary source of nest failure.
• Where nest-predation occurred, Corvids were identified as the primary nest predators followed by mammals.
  • For the first time in Washington a bobcat was identified as having depredated the eggs from a plover nest.

Fledging Success 

• The average number of young fledged per adult male on the three Washington nesting sites was 1.7 (1.55-1.83). Population viability analyses has indicated that, on average, at least one young must fledge per adult male to have a stable population (Nur et al. 1999). The fledging rate for the past five years has been approximately 1.0 or greater which suggests a stable to growing population.

Management Actions 

• Nest exclosures: No nests were exclosed in 2017.
• 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 both private and publicly owned beach at Midway Beach were signed to restrict human access to critical nesting areas. Access restrictions on private land at Midway Beach occurred when permitted by the land owner.
• 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: Clam digging was prohibited during most of the season due to high levels of the toxin domoic acid. A total of 20 days were open to recreational razor clamming at Long Beach in 2017, eleven of which overlapped with plover breeding season. Clam digs occurred on 10 days in April and 1 day in May. A bonus limit for clams was allowed, going up from 15 clams to 25, for late April/early May. Portable toilets were again placed on the beach at Leadbetter to minimize intrusions into the closed nesting habitat.
  • Midway Beach: Clam digging occurred on 15 days during the plover breeding season in April
• Nest Predation: Predator management was conducted by wildlife specialists with USDA APHIS Wildlife Services on both Leadbetter Point and Midway/Grayland Beach in 2017. Predator management consisted of dispersing birds or performing targeted lethal removal of known nest 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: The Willapa NWR habitat restoration area (HRA) increased by 100 acres via bulldozer and discing.
  • A 200 meter wide strip of pine forest, totaling 70 acres was removed adjacent to the HRA