2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
Bay, NS2 is located within Zone 42 of the southern MTB, and NS3 is located in Zone 14 of the FFTB.
Western snowy plover nest sites included all tern colonies listed above but also included the Seasonal
Ponds (Zones 1 through 37).
The principal survey effort for California least tern and western snowy plover was undertaken by
CDFG seasonal staff member, Peter Knapp and assisted on NS1 by Kelly O’Reilly, CDFG. Merkel &
Associates biologist, Bonnie Peterson, participated intermittently in the survey efforts as support and to
aid in collecting data for report preparation. STI and NS1 were surveyed by vehicle from the West
Levee Road prior to arrival of the least terns and then on foot. NTI was used primarily by nesting
elegant terns and black skimmers and therefore required minimal monitoring for least terns and
plovers. Observations were made from the West Levee Road. NS2 was surveyed by vehicle from the
East Levee Road weekly using a spotting scope and once a month on foot. NS3 was surveyed by
vehicle from the north end of the site. The large majority of suitable western snowy plover nesting
habitat in the Seasonal Ponds was visible from the road network. The observer(s) would slowly drive
along the roads that subdivide this area. Frequent stops were made to examine specific areas adjacent
to the road with binoculars or spotting scope without exiting the vehicle.
NS1, NS2, and NS3 are sectioned by markers, which form the basis for data recording. NS1 is
sectioned south to north from A though CC in a regular grid. Each least tern and snowy plover nest
located on NS1 was marked with a numbered tongue depressor and mapped for ease of relocation on
subsequent visits.
Beginning in late-March, surveys for nesting western snowy plovers were conducted at least twice a
week, sometimes 4 or 5 times a week, until the beginning of September. Data collected included the
gender of the incubating adult, length of incubation (days), number of eggs in the clutch, condition of
the nest (e.g. signs of disturbance), and the fate of each nest (hatched, predated, or abandoned). Close
examination of nests was usually conducted only once or twice per nest. As snowy plover nests were
located they were protected by Mini-Exclosures (MEs), which were placed over the nest.
Observations of snowy plover broods were made 3 to 5 days per week. It was usually possible to
follow the movements and determine the fate of the chicks from each brood since there was sufficient
dispersion over space and time to differentiate between broods. These regular brood observations were
conducted to determine chick survival or fledgling production, as well as to detect movement between
zones and use of specific zones for brood rearing.
California least tern monitoring began as soon as the terns started arriving at Bolsa Chica in mid-April
and continued until the terns fledged and left the breeding grounds in late August. The observers
would walk active tern colonies and mark and record the section of all new nests. This activity
typically occurred between 0800 and 1200 hours, 1 to 2 times per week. Observers would record any
hatched, abandoned or depredated nests. Any signs of disturbance within the tern colonies were also
recorded. At other times during the week, observations on the status of the colony were made from
observation points outside of the colony. Observations of least tern chicks and fledglings were made
every 1 to 2 days to determine hatching and fledging success.
In 2008, monitoring of nests on NS1 was very difficult due to the large number of nesting birds besides
the western snowy plover and California least tern, including elegant tern, black skimmer, royal tern,
and Caspian tern. These species previously nested primarily on NTI. By the end of June, monitoring
Merkel & Associates, Inc. 92