1. Methods Results/Discussion
Effects of Nest Monitoring Techniques on Western
Snowy Plover Behavior
Jilma Rachel Guinea1 & Dr. Jeanette Boylan2
1Department of Wildlife, Humboldt State University, Arcata, CA 95521
2San Diego Zoo Global Institute for Conservation Research
Acknowledgements
Walter J. and Betty C. Zable Foundation Summer Fellow
Coronado Field Crew: Katrina, Maggie, Julia, Melissa, Stephanie, Christy, Monica
Camp Pendleton Field Crew: Travis, Rachel, Demetri, Andrew, Anjanette, Monica, Amie
Tiffany Shepherd, Wildlife Biologist, Naval Base Coronado
Sparrow McMorran, Beach Biologist, Marine Corps Base Camp Pendleton
This research was partially funded by the Department of the Navy, U.S. Pacific Fleet, on behalf of Naval Base Coronado
Figure 2. Southern California’s military bases used for Western
Snowy Plover research during the months of June and July 2015.
Objective
Ø Hypothesized that a direct approach during a nest-check would
create more intense disturbance than the indirect approach of
transect-walks.
Ø Alternatively, if time within proximity of a nest predicts level of
behavioral response, then brief nest-checks may constitute a
lesser disturbance than the more time-intensive transect-walks.
Study sites broken down into
three disturbance levels:
Ø Low (both bases)
• Restricted access
Ø Medium (NBC only)
• Military training
• Terns
Ø High (NBC only)
• Recreational beaches
Ø Focal observations were conducted on incubating WSPL during
normal surveying activities.
Ø Data collected:
• Distance (m) monitor was when plover:
• Time (min) monitor in alert radius (based on distance WSPL
first became alert)
• Time off Nest: time flushed from nest – time returned to nest
• Disturbance Time: time of alert behavior – time returned to
nest
• Presence/absence of anti-predator displays within disturbance
levels
• flushed • returned• became alert
Introduction
Ø The San Diego Zoo Institute for Conservation Research has
been working in partnership with Naval Base Coronado (NBC)
and Marine Corps Base Camp Pendleton (MCBCP) in
Southern California to investigate Western Snowy Plover
(WSPL) reproductive success.
Ø WSPL Pacific coast populations are federally listed as
threatened.
Ø Summer research project to investigate whether conservation
monitoring techniques differed in impact to nesting WSPL.
Ø Flight initiation was instigated at a greater distance during
transect-walks than nest-checks (fig. 3).
Ø Monitors spent greater amounts of time within the alert
radius of WSPL during transect-walks (P = 0.001).
Ø WSPL spent more time off nests during transect-walks (P =
0.001), resulting in a greater disturbance time (fig. 4).
Ø Plovers displayed more anti-predator behaviors during
transect walks than nest checks.
• greater proportion of the displays were seen in low
disturbance areas of MCBCP (P = 0.018)
Ø More in depth studies of monitoring as a disturbance factor
needed for more robust analyses and conclusions.
• disturbance levels
• effects on fitness
Ø Implement modifications to current protocol
• innovative techniques
• terns nesting nearby
Figure 3. Distance to a monitor when incubating snowy plovers flushed from their nests during both approach types. Transect-walks
instigated flushing when monitors were at a further distance than nest-checks (P = 0.001 ).
Figure 4. Duration that plovers were disturbed during both approach types. Transect- walks had a greater total disturbance time between
the two approaches (P = 0.005).
© Aquarium of the Pacific © Mike Baird
Figure 5. Snowy plover performing anti-predator displays – the horizontal run (A) is done for threats that are not perceived as
immediate, while the broken-wing display (B) is exhibited when a greater threat is presented.
Figure 1. Simulated tracks of the two approach types a monitor used during the surveys – transect-walks (A) are intensive searches
and nest-checks (B) are quick checks of a nest's status.
A B
© Kurt Rogers, SFC
A
© Michael D Kern
B