Human dimensions of predator management for threatened Western Snowy Plovers

Wader Study ◽  
2021 ◽  
Vol 128 (1) ◽  
Author(s):  
Barbara Clucas
Keyword(s):  
Human Dimensions ◽  
Predator Management ◽  
Snowy Plovers ◽  
Western Snowy Plovers

scholarly journals Factors influencing the abundance of wintering western snowy plovers at Crown Memorial State Beach

2021 ◽  
Vol 107 (3) ◽  
pp. 249-259
Author(s):  
David L. Riensche
Keyword(s):  
Prey Availability ◽  
Habitat Choice ◽  
Protection Zone ◽  
The Public ◽  
Nonbreeding Season ◽  
Significant Difference ◽  
Food Shortages ◽  
Snowy Plovers ◽  
Shorebird Habitat ◽  
Western Snowy Plovers

Survival during the nonbreeding season, when mortality from food shortages and raptor predation is highest, influences shorebird population growth. These selection pressures, as well as anthropogenic influences, can shape wintering shorebird habitat use patterns. The western snowy plover (Charadrius alexandrinus nivosus) is a small shorebird that uses sand-spits, dune-backed beaches, open areas around estuaries for foraging and roosting. The Pacific Coast population of western snowy plovers is listed as a federally threatened species and a California Species of Special Concern. Previous studies suggest humans, dogs and corvids are sources of disturbance to plovers on public beaches. During 2014 to 2019, these disturbance factors were examined at Robert W. Crown Memorial State Beach in Alameda, California. In decreasing order of impact, the beach using public, corvids, and dogs were found to be the major stressors to over wintering plovers. Both the public and corvids respectively, resulted in disturbance and avoidance behaviors by plovers nearly 40% of the time. In 2015, the District created the Plover Protection Zone (PPZ) by installing symbolic fencing, signage, and establishing a volunteer team to monitor plovers and educate the public. In 2016, the potential prey abundance within the plover protection zone and areas directly north and south were examined using core samples and sticky traps. Statistical analysis showed a significant difference in the amount of macro-invertebrate prey available in the area used by the plovers as compared to other locations. Habitat choice and prey availability are vital to wintering shorebird. During this study, the wintering population of western snowy plovers increased from six to over 54 individuals.

scholarly journals Effects of nest success and mate fidelity on breeding dispersal in a population of Snowy Plovers Charadrius nivosus

2013 ◽  
Vol 24 (3) ◽  
pp. 342-353 ◽  
Author(s):  
WENDY J. PEARSON ◽  
MARK A. COLWELL
Keyword(s):  
Dispersal Distance ◽  
Breeding Dispersal ◽  
Nest Failure ◽  
Mate Fidelity ◽  
Median Distance ◽  
Predator Management ◽  
Mate Change ◽  
Snowy Plover ◽  
Snowy Plovers ◽  
Hatching Eggs

SummaryBreeding dispersal subsequent to nest failure is hypothesised to be a behavioural response to danger posed by nest predators. We used histories and locations of male and female Snowy Plover Charadrius nivosus nests in northern California over a 10-year period to examine effects of nest fate, mate fidelity, residency, predator exclosures, and age on dispersal distance. Within years, females moved a median distance of 2.2 km after changing mates; males moved a median of 0.9 km. Between years, plovers moved the shortest distances when they retained a mate from the prior year and were successful in hatching eggs (males = 0.2 km, females = 0.3 km). Both females (13.0 km) and males (2.6 km) dispersed farther when mate change coincided with nest failure in the prior year. The observation that most plovers did not disperse far enough to move away from sites where predators are abundant and have strong effects on plover reproductive success suggests that effective predator management will be challenging.

scholarly journals Using Decision Science for Monitoring Threatened Western Snowy Plovers to Inform Recovery

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 569
Author(s):  
Bruce G. Marcot ◽  
James E. Lyons ◽  
Daniel C. Elbert ◽  
Laura Todd
Keyword(s):  
Performance Measures ◽  
Risk Attitude ◽  
Cost Effective ◽  
Monitoring Methods ◽  
Optimal Decisions ◽  
The Us ◽  
Fish And Wildlife Service ◽  
Snowy Plovers ◽  
On The Road ◽  
Western Snowy Plovers

Western Snowy Plovers (Charadrius nivosus nivosus) are federally listed under the US Endangered Species Act as Threatened. They occur along the US Pacific coastline and are threatened by habitat loss and destruction and excessive levels of predation and human disturbance. Populations have been monitored since the 1970s for distribution, reproduction, and survival. Since the species was federally listed in 1993 and a recovery plan was approved under the US Fish and Wildlife Service in 2007, recovery actions have resulted in growing populations with increased presence at breeding and wintering sites throughout their Pacific Coast range. This success has created logistical challenges related to monitoring a recovering species and a need for identifying and instituting the best monitoring approach given recovery goals, budgets, and the likelihood of monitoring success. We devised and implemented a structured decision analysis to evaluate nine alternative monitoring strategies. The analysis included inviting plover biologists involved in monitoring to score each strategy according to a suite of performance measures. Using multi-attribute utility theory, we combined scores across the performance measures for each monitoring strategy, and applied weighted utility values to show the implications of tradeoffs and find optimal decisions. We evaluated four scenarios for weighting the monitoring objectives and how risk attitude affects optimal decisions. This resulted in identifying six strategies that best meet recovery needs and were Pareto optimal for cost-effective monitoring. Results were presented to the US Fish and Wildlife Service, responsible for monitoring as well as for consideration to ensure consistent monitoring methods across the species’ range. Our use of structured decision-making can be applied to cases of other species once imperiled but now on the road to recovery.

Monitoring Western Snowy Plover Nests with Remote Surveillance Systems in San Francisco Bay, California

2012 ◽  
Vol 3 (1) ◽  
pp. 123-132 ◽  
Author(s):  
Scott A. Demers ◽  
Catilin W. Robinson-Nilsen
Keyword(s):  
San Francisco ◽  
Human Disturbance ◽  
Surveillance System ◽  
Management Practices ◽  
San Francisco Bay ◽  
Behavioral Studies ◽  
Snowy Plover ◽  
Snowy Plovers ◽  
Nest Predators ◽  
Western Snowy Plovers

Abstract The western snowy plover Charadrius nivosus nivosus is listed as threatened under the U.S. Endangered Species Act of 1973 due to long-term population declines related, in part, to nest predation and human disturbance. In San Francisco Bay, California, numbers of predators of western snowy plovers and the potential for recreation-based human disturbances have increased during the past few decades and will likely increase for the foreseeable future. In an attempt to increase the reproductive success of western snowy plovers, managers have dedicated considerable resources to management practices including predator removal and habitat enhancement projects in San Francisco Bay. The unequivocal identification of western snowy plover nest predators and information regarding the behavioral responses of nesting plovers to human disturbance would inform management practices for this species. Therefore, we examined the efficacy of using a digital video surveillance system to identify nest predators of western snowy plovers in former salt evaporation ponds in San Francisco Bay and to assess its potential for use in behavioral studies. This system was designed to minimize disturbance to nesting plovers and limit predator bias at breeding sites that had little or no cover to camouflage or protect the equipment. The system included a small camera with infrared lights placed approximately 20 m from nests and a continuously operating recording unit and power supply that was positioned up to 300 m from nests. The system could be deployed within 20 min, run continuously for up to 5 d, and data could be retrieved without disturbing nesting birds. During a 2-y study period, we recorded six species depredating plover eggs and chicks: red-tailed hawk Buteo jamaicensis, common raven Corvus corax, California gull Larus californicus, northern harrier Circus cyaneus, ruddy turnstone Arenaria interpres, and gray fox Urocyon cinereoargenteus. Our results suggest that this surveillance system was effective for identifying western snowy plover nest predators, and the presence of the camera did not influence nesting success of monitored nests. This system could be integrated into conservation programs intended to improve reproductive success of this species and could be useful for conducting behavioral studies of western snowy plovers and other species.

Western Snowy Plovers Charadrius alexandrinus nivosus select nesting substrates that enhance egg crypsis and improve nest survival

Ibis ◽  
2011 ◽  
Vol 153 (2) ◽  
pp. 303-311 ◽  
Author(s):  
MARK A. COLWELL ◽  
JASON J. MEYER ◽  
MICHAEL A. HARDY ◽  
SEAN E. MCALLISTER ◽  
AMBER N. TRANSOU ◽  
...  
Keyword(s):  
Nest Survival ◽  
Charadrius Alexandrinus ◽  
Snowy Plovers ◽  
Egg Crypsis ◽  
Western Snowy Plovers
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