Secret Lives of Seabirds-A Year of Discovery on Santa Barbara Island

Adult Scripps's Murrelet in nest on Santa Barbara Island. (Laurie Harvey, CIES)

The Santa Barbara Island seabird habitat restoration project entered its fifth year in 2013. Only one square mile in area, Santa Barbara Island (SBI) is the smallest island in the Channel Islands National Park. The island has no natural land predators, which makes it a haven for seabirds. Santa Barbara Island has the largest colony of Scripps’s Murrelet in the United States. The Scripps’s Murrelet is a small black and white seabird in the Auk family with a small head and thin sharp bill. One of our goals for this project is to restore selected areas that can serve as high quality nesting habitat. To meet this goal, biologists are removing non-native plants and then restoring this habitat by planting native species.

An exciting discovery this season was the capture of a Scripps’s Murrelet previously-banded in 1995. Based on the data recorded when the bird was first banded, this adult is estimated to be at least 18 years old. This is thought to be one of the oldest known recaptures of a Scripps’s Murrelet. Nesting of Scripps’s Murrelets also started early this year with the first nest being laid on February 2, 2013. The early nester successfully hatched both eggs on March 17, 2013, which is  the earliest recorded hatching date for this species on Santa Barbara Island.

Scripps’s Murrelets nest at three main locations on the island which are monitored throughout the season: Arch Point North Cliffs, Cat Canyon, and Landing Cove. This year, MSRP biologists found 241 nests which is an increase from the 160 nests found in 2012. Of the 241 nests, biologists noted that 160 fledged (left the nest) successfully. Biologists discovered that the highest hatch rates of Scripps’s Murrelets were documented at Landing Cove, and the lowest rate was at Cat Canyon. Landing Cove is mostly restored native shrub habitat, while Cat Canyon is mostly rocky crevice habitat and not a restoration site. This increase is encouraging and a sign that the project is providing high quality nesting habitat.

Our ongoing banding efforts and video monitoring projects may help to answer interesting questions such as the timing of nesting and the apparent use of nests twice in one season. Forty-nine Scripps’s murrelets were banded at SBI in 2013, including 2 chicks. Biologists collected approximately 6000 hours of video footage this season from nest cameras. These cameras recorded interesting nesting behavior previously undocumented. Biologists also captured the first ever audio recording of a Scripps’s Murrelet chick’s vocalizations during a banding effort.

In addition to the Scripps Murrelets, Cassin’s Auklets were found nesting at multiple sites at Arch Point North Cliffs and at Elephant Seal Cove. Another member of the Alcid Family, this small seabird was almost completely eliminated from the island by feral cats that preyed on the adults and chicks. MSRP’s habitat restoration efforts are also benefiting this species. Another rare California endemic species, the Ashy Storm-petrel, was also documented nesting at multiple locations at Arch Point North Cliffs.

The success of this year’s breeding season is very encouraging for MSRP’s on-going restoration work. Habitat restoration work and monitoring will continue for several more years with many more interesting discoveries to come!

 

-Jennifer Boyce, MSRP Program Manager