COMMISSION

fledged an average of 148 birds per year. During this same period, the park had an average
of 1.51 fledglings per breeding male, which exceeds the 1.2 ratio that is expected to allow
for moderate population growth as per the Recovery Plan for this species. The fledgling rate
in 2014 was 35.8 percent (196/547), which is similar to the average rate of 36.7 percent for
the last 11 years, but the park’s population is definitely growing. Oceano Dunes SVRA had
the highest total number of breeding adults (226) and fledges
produced in 2014.
Western snowy plover chicks
In 2015, there were a minimum of 205 breeding birds,
compared to 226 in 2014. This is a decrease of 9.3 percent
from the minimum estimated number of 226 breeding adults
in 2014 and compares to a range of 95-190 adults for 2008-
2013. The average minimum number of breeding adults for the
last five years (2011-2015) is 189, increasing to 198 for the last
three years.
Ongoing HMS Survey with California Polytechnic State University
Ongoing HMS surveys at Oceano Dunes SVRA include shorebird and terrestrial birds,
small and large mammals, herpetological resources, fish, and vegetation. Oceano Dunes
SVRA resources staff have been working closely with Dr. Villablanca, a professor from the
California Polytechnic State University (Cal Poly), San Luis Obispo, to provide technical
assistance and consultation on most of the SVRA’s monitoring methods. Since 2014,
Dr. Villablanca has helped update, refine, and standardize Oceano Dunes SVRA’s small
mammal study design to conform to experimental design principles. Together, the SVRA
and Dr. Villablanca selected 11 treatment and control locations that include habitat islands
in the OHV riding areas and in non-riding areas. A systematic and standardized approach
for selecting the small mammal monitoring plots involved mapping the vegetation alliances
in the park following the Manual of California Vegetation. Two alliances were found to be
most common: Silver Beach Lupine/Mock Heather alliance and the Willow/Wax Myrtle
alliance. Consequently, all monitoring plots were placed so they contained 50 percent of
the Silver Beach Lupine/Mock Heather alliance and 50 percent of the Willow/Wax Myrtle
alliance.
Oceano Dunes SVRA has surveyed 11 plots every three
months since October 2014. The survey sessions involved
putting 352 Sherman live traps on 11 plots (32 traps per
plot). Staff checked the traps each morning and baited
them each night for three consecutive days. Captured
small mammals are identified to species; their sex and
reproductive condition are determined; and each received
Cal Poly students
2017 Program Report 149