Ashy Storm-Petrel Range and Colony Attendance Behavior

Science Center Objects

Together with Federal and non-profit partners, WERC's Josh Adams and team are using cutting-edge technology to study the range and population attendance patterns of the Ashy Storm-petrel, an elusive seabird found throughout a large portion of the California Coastal National Monument. Their research will inform management and conservation for this species and other seabirds that use California’s offshore rocks and islands.

Emma Kelsey of the USGS preparing a song meter for deployment on Hurricane Rock in Big Sur, Monterey County (photo by SeanPaul L

Emma Kelsey of the USGS preparing a song meter for deployment on Hurricane Rock in Big Sur, Monterey County. (Credit: SeanPaul La Selle, USGS Pacific Region. Public domain.)

Ashy storm-petrel (Oceanodroma homochroa) with metal identification band being held by a USGS researcher

Ashy storm-petrel (Oceanodroma homochroa) with metal identification band being held by a USGS researcher. (Credit: Max Czapanskiy, USGS Pacific Region. Public domain.)

Scientific studies provide a “launch pad” for resource management and conservation

The California Coastal National Monument (CCNM) includes over 20,000 offshore rocks, sea stacks, and islands off the California coast. These offshore ecosystems provide prime real estate for wildlife, including more than 200,000 breeding seabirds and thousands of marine mammals. However, information about the wildlife resources of the CCNM remains unknown, and this can create challenges for resource managers looking to manage, conserve or preserve the monument’s ecosystems.

To inform management and conservation efforts within the CCNM, Dr. Josh Adams and team are studying the range/distribution and attendance patterns of the Ashy Storm-petrel (Oceanodroma homochroa). Although it presently has no federal status for protection (USFWS 2015), the Ashy Storm-Petrel nests primarily within the CCNM boundaries and is considered “Endangered” by the International Union for Conservation of Nature (Bird Life International 2013). Ashys nest in burrows and crevices on offshore rocks and islands, and to avoid predators, adults and non-breeding prospectors only arrive and depart their island nests under the cover of darkness.

 

Smart planning, collaboration, and novel technology overcome challenges in the field

Whereas these behaviors help storm-petrels avoid predators, they also make it difficult for biologists to study them in the field. To overcome these challenges, the WERC seabird team and Conservation Metrics Inc. have partnered to collaborate with the Bureau of Land Management Central Coast Field Office, Channel Islands National Park, Point Reyes National Seashore, Redwood State and National Parks, USFWS, US Navy, Oikonos, and California Institute for Wildlife Studies to use novel technology to monitor storm-petrel attendance with minimal impact to sensitive habitats.

USGS scientists deployed passive acoustic recorders on 26 rocks and islands within the CCNM. The recorders capture the calls of several species of storm-petrels and other nocturnal species returning to offshore colonies at night. The team is also interested in three additional storm-petrel species breeding within the CCNM: Leach’s Storm-Petrel (O. leucorhoa), Fork-tailed Storm-Petrel (O. furcata), and Black Storm-Petrel (O. melania). In addition, the researchers’ acoustic surveys may also capture the vocalizations of other sensitive seabirds including Tufted Puffin (Fratercula cirrhata), Scripps’s (Synthliboramphus scrippsi), and Guadalupe (S. hypoleucus) Murrelets.

Understanding the status of sensitive seabird populations within the Monument will help establish the scientific basis for future management, conservation and monitoring efforts. This project assesses the use of passive acoustic surveys to ascertain trends in relative abundance and habitat-use among crevice and burrow-nesting seabirds within the CCNM. The results of this study will generate data on the status and distribution of Ashy Storm-Petrels and other important seabird species in the CCNM, and will also provide land and wildlife managers with insight into new, effective, affordable, and repeatable methods for monitoring species throughout the Monument.