Article and photos by Amelia O'Connor,
Audubon Society of Portland
Amelia lives in Otter Rock, OR, is a local surfer, and holds a master's in Marine Resource Management from OSU, She has been working as a field coordinator for Audubon Society of Portland's coastal community science projects since 2014. She is a science adviser to 2018 Sitka Art Invitational artist Nora Sherwood, who has created works for this year's exhibit reflecting on seabird parent/offspring relationships.
When I think about a top predator in Oregon's ocean food web a few species come to mind, like the Great White Shark and tuna or marine mammals like Orcas and sealions. Rarely do seabirds come to mind as being high in the trophic ladder.
However, common seabirds like cormorants and murres that you might see any day looking offshore from a rocky headland or beyond the breaking waves of a sandy beach depend on the same schooling fish that the tuna, seals, sharks and salmon eat. These fish, commonly referred to as "forage fish," include a wide range of species from the more well-known and historically economically important Northern Anchovy and Pacific Sardines, to less commonly known fish like the Pacific Sand Lance and Silversides among many others. In fact, these forage fish support most of our nearshore food web and are an excellent indicator to ocean health, although monitoring them can be tricky. For this reason, nearshore fish-eating seabirds that nest on the Oregon Coast including Common Murres, Brandt's and Pelagic Cormorants, and Western Gulls among others can be useful indicators to the productivity of our nearshore ocean environment.
In 2012, five marine reserves and protected area complexes were designated in Oregon by the state legislature to conserve marine habitats and biodiversity and facilitate scientific research. Part of the reason for creating these protected areas was to increase protections for forage fish species because of their recognized importance in the food web. In 2014, Audubon Society of Portland and the US Fish and Wildlife Service (USFWS) started a community science project to complement Oregon Department of Fish and Wildlife fish monitoring by tracking select seabird nests both inside and outside of the Cape Perpetua Marine Reserve to see how successfully seabirds produce young in Oregon's largest Marine Reserve. In 2016 we expanded the project to include the Cape Falcon Marine Reserve in partnership with Friends of Cape Falcon and Haystack Rock Awareness Program.
During the summer breeding season, we monitor roughly 100 Brandt's, Pelagic and Double-crested cormorant nests annually to help establish baseline data for the marine reserves. Our weekly monitoring visits include checking the contents of selected nests in colonies. We rely on a trained team of volunteer community scientists to help collect the data. Monitoring seabirds takes patience. We use binoculars and scopes to closely watch incubating seabirds on their nests. When the birds get up off their nests and their mate takes over nest duties we quickly examine the nest for eggs or chicks. Over weeks of monitoring we can determine if eggs successfully hatch and young fledge. We also record weather conditions, documenting avian predators and any disturbances to the colonies. Over the past five years and with the help of a USFWS intern and over 50 community scientists, we've compiled baseline data that has started to reveal how nesting seabirds are faring at these sites.
There are many ways to measure how successful a nest is, but a commonly used method for cormorants is breeding productivity or the average number of fledglings (chicks old enough to fly) produced per nest. Over the past five years we have seen a lot of variability between years, sites and species. Double-crested Cormorants generally have had the highest breeding productivity, averaging over two fledglings per nest across our five years of monitoring with only a few exceptions. Brandt's and Pelagic have shown more variability between years, ranging from less than one to just over two fledglings per nest and zero to almost three fledglings per nest, respectively.
More than just food availability (nearshore fish abundance) will affect breeding success for these birds. We have documented chicks lost to predation by eagles and weather events from early summer storms to late summer heat waves. In part due to a lack of storms this summer, chicks fledged nearly a month earlier than in previous years, and 2018 was a good year for all three species at our monitored sites. In addition to monitoring, an important goal for us is to connect with the public on the conservation challenges seabirds face. Many seabird species are declining and so it's important that the voting public understand these issues so they can help support policies to protect seabirds and their habitats. We've been lucky to partner with a local business, Sea Lion Caves at Cape Perpetua which affords us the opportunity to reach many members of the public on our monitoring efforts and seabird conservation. In the past five years we've reached out to thousands of visitors.
As seabirds like cormorants can be helpful indicators to nearshore ocean environment, shorebirds like the Black Oystercatchers are excellent indicators to our intertidal environment. Oystercatchers feed in the rocky intertidal zone primarily on mussels and nest on nearshore rocks and rocky headlands. Like cormorants, oystercatchers are an ideal bird for community science because they are large and easy to identify with their bright orange bills and pink feet contrasting with their black feathers. They are also considered a species of concern due to their low population numbers on the Oregon Coast.
In 2015, Portland Audubon and USFWS started a Black Oystercatcher Monitoring community science project to continue the US Geological Survey's (USGS) abundance surveys that were discontinued after 2006. With the help of over 80 trained volunteers conducting surveys to cover the rocky intertidal areas of the entire Oregon Coast, we completed our fourth year of abundance surveys this summer. Our findings indicate that the Black Oystercatcher numbers may have increased from the 325 estimated by the USGS in 2006 to over 500 individuals. Through these surveys and opportunistic nest monitoring our community scientists have also helped inform the USFWS of human disturbance problem areas where additional signage has been posted and our data have also been used to inform management planning.
We aim to continue both these projects in 2019 to continue collecting baseline data for seabird breeding success in the Marine Reserves and determine population trends and breeding success of Black Oystercatchers on the Oregon Coast. We are always looking for more volunteers to expand these community science projects like our Seabird Monitoring in Oregon's Marine Reserves and Black Oystercatcher Monitoring projects, but there are many other opportunities including Snowy Plover and Marbled Murrelet monitoring. Visit this link to learn more about volunteer opportunities as well as our annual reports and monitoring results, or email for more info.
Seabird Monitoring in the Cape Falcon Marine Reserve
Brandt's Cormorant colony in the Cape Perpetua Marine Protected area
Black Oystercatcher and young chick eating a mussel near Otter Rock