Seabird Restoration:
Restore Alcids to Santa Barbara Island
Background
The goals of this action are to re-establish a once-active Cassin’s auklet
breeding population and restore the state-threatened Xantus’s murrelet on Santa
Barbara Island. The Cassin’s auklet population was decimated by cats that were
introduced to the island in the late 1800s. Efforts to re-establish the
Cassin’s auklet colony will include using social facilitation methods (e.g.,
vocalization playback systems to attract other individuals), installing nest
boxes, and improving habitat through the removal of non-native vegetation from
historical nesting areas and revegetation with native plants.
Santa Barbara Island is home to the largest colony of Xantus’s murrelets in
California despite a documented population decline over the last 20 years.
Because some Xantus’s murrelet nest sites have been lost due to reduction in
shrub cover on the island, this action will provide secure nesting area for
this species. Eggshell thinning and/or elevated levels of DDTs were documented
in the eggs of both of these species in the Southern California Bight.
The main objectives of this habitat effort are to restore Cassin’s auklets and
Xantus’s murrelets by: (1) increasing recruitment, (2) increasing reproductive
output, and (3) decreasing egg and chick mortality by providing safe breeding
habitat.
(Santa Barbara Island Film)
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Project Updates
Biological Surveys
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Biologists expanded biological surveys this year including spotlight surveys,
prey sampling, at-sea radial surveys, banding seabirds (Cassin’s auklets,
Xantus’s murrelets, and ashy storm petrels), nest surveys, barn owl predation
surveys, and surveys of other species by boat.
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Biologists found the first nesting Cassin’s auklet on Santa Barbara Island
since the 1990s!
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Biologists also encountered Cassin’s auklets flying close to where sounds of
these seabirds are being broadcast as an attraction technique.
Habitat Restoration
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Four restoration sites are established on Santa Barbara Island representing 4.5
acres and 7,000 plants total have been placed in the ground since restoration
began.
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Biologists grow all native plants in a nursery on the island that is
self-watering, prepare areas to be planted by removing non-native plants, and
collect data before and after planting (pre-planting surveys, outplanting
success).
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Year one plant survival was 43% for Prohibition Point and 62% for Northeast
Flats sites. The Elephant Seal Cove restoration site was added this year.
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