2007 Annual Monitoring Report (pdf 16MB) - Bolsa Chica Lowlands ...

Bolsa Chica Lowlands Restoration Monitoring2007 Annual ReportCalifornia Least Tern and Western Snowy Plover MonitoringMethodologyCalifornia least tern (Sternula antillarum browni) nest monitoring occurred on North Tern Island(NTI), South Tern Island (STI), Nest Site 1 (NS1), Nest Site 2 (NS2), and Nest Site 3 (NS3). NTI andSTI are located in Inner Bolsa Bay, outside of the project survey area, but are included in this report inorder to give a more complete understanding of tern reproductive success at the Bolsa Chica complex.NS1, NS2, and NS3 are newly created nesting islands within the project area; NS1 is in the FTBbetween the FTB and Inner Bolsa Bay, NS2 is located within Zone 42 of the southern MTB, and NS3is located in Zone 14 of the FFTB. Western snowy plover (Charadrius alexandrinus nivosus) nestsites included all tern colonies listed above but also included the Seasonal Ponds (Zones 1 through 37).The principal survey effort for least terns and western snowy plover was undertaken by CaliforniaDepartment of Fish & Game seasonal staff member, Peter Knapp. Merkel & Associates biologist,Bonnie Peterson, participated intermittently in the survey efforts as support and to aid in collectingdata for report preparation. STI and NS1 were surveyed by vehicle from the West Levee Road prior toarrival of the least terns and then on foot. NTI was used primarily by nesting elegant terns (Thalasseuselegans) and black skimmers (Rynchops niger) and therefore required minimal monitoring for ternsand plovers. NS2 was surveyed by vehicle from the East Levee Road weekly using a spotting scopeand once a month on foot. NS3 was surveyed by vehicle from the north end of the site. The largemajority of suitable western snowy plover nesting habitat in the Seasonal Ponds was visible from theroad network. The observer(s) would slowly drive along the roads that subdivide this area. Frequentstops were made to examine specific areas adjacent to the road with binoculars or spotting scopewithout exiting the vehicle.NS1, NS2, and NS3 are sectioned by markers, which form the basis for data recording. NS1 issectioned south to north from A though CC in a regular grid. Each least tern and snowy plover nestlocated on NS1 was marked with a numbered tongue depressor and mapped for ease of relocation onsubsequent visits.California least tern monitoring began as soon as the terns started arriving at Bolsa Chica in mid-Apriland continued until the terns had fledged and left the breeding grounds in late August. The observerswould walk active tern colonies and mark and record the section of all new nests. This activitytypically occurred between 0800 and 1200 hours, 1 to 2 times per week. Observers would record anyhatched, abandoned or depredated nests. Any signs of disturbance within the tern colonies were alsorecorded. At other times during the week, observations on the status of the colony were made fromobservation points outside of the colony. Observations on least tern chicks and fledglings were madeevery 1 to 2 days to determine hatching and fledging success.Beginning late-March, surveys for nesting western snowy plovers were conducted at least twice aweek, sometimes 4 or 5 times a week, until the beginning of September. Data collected during thisstudy included the gender of the incubating adult, length of incubation (days), number of eggs in theclutch, condition of the nest (e.g. signs of disturbance), and the fate of each nest (hatched, predated, orabandoned). Observations of western snowy plover distribution were also recorded by cell number,throughout the study area, not just those birds associated with nests. Close examination of nests wasusually conducted only once or twice per nest. As snowy plover nests were located they wereprotected by Mini-Exclosures (MEs) placed over the nest.Merkel & Associates, Inc. 53