Restoring Southeast Farallon Island thru mouse eradication: Yes

Islands are special

In contrast to continents, their ecosystems have much fewer moving parts. It’s not unusual for an island to have only a few plant species and often no land bird or mammal species. All of New Zealand has no native land mammals except for bats. The Channel Islands off southern California have only a native deer mouse and the island fox, and that’s only on some of the islands. Southeast Farallon Island has no native land mammals.

I’ve had the privilege of being on Southeast Farallon twice. It’s a magical place, home to thousands of seabirds and marine mammals.

Yet islands are critical refuges for marine mammals and seabirds. It’s not unusual for over 90% of a single species to come from a single island, or just a few islands. For example, over 99% of the world’s Heermann’s Gulls breed only on Isla Raza, a 1.5 acre postage stamp in the Sea of Cortez. 95% of the world’s Black-vented Shearwaters breed only on San Benito Island off Baja California. 99% of the world’s Scripps’s Murrelets come from four islands off southern California and Baja California. And probably 50% of the world’s Ashy Storm-Petrels nest in burrows on a single hillside on Southeast Farallon Island. There are similar examples from all over the world.

A new 4-minute video by Point Blue, summarizing the project.

Islands are vulnerable

This gets us to the final characteristic about islands; they are vulnerable to perturbations. Add one more moving part, and things can fall apart quickly. 75% of all bird, mammal, amphibian, and reptile extinctions have occurred on islands. More bird species have gone extinct on the Hawaiian Islands than on North America, South America, Europe, Africa, Asia, and Australasia combined.

The introduction of a single non-native species, such as rats or mice or cats or even rabbits, can result in massive changes to an island’s ecology, leading to the extinction of native or breeding species. Rats, arriving as stowaways on ships, are the number one cause of bird extinctions worldwide.

Scripps’s Murrelet nest success on Anacapa Island, before and after rat eradication.

When I worked for the California Department of Fish and Wildlife, I was involved in over 300 restoration projects. The best one, the one with the most obvious and dramatic benefits, was when we eradicated non-native black rats from Anacapa Island. In addition to benefitting Scripps’s Murrelets, other seabirds such as Cassin’s Auklets began nesting on the island. The native lizard and even the sea stars and mussels and vegetation rebounded; the rats had been eating them all out of house and home.

Here’s the 4-minute version about Anacapa restoration ten years after rat eradication.

The mouse problem on Southeast Farallon Island

Today, the non-native house mouse is impacting the Farallon Islands, one of the most important seabird nesting colonies south of Alaska.

Southeast Farallon Island, the main island, is infested with the mouse. In fact, there are higher densities of house mice there (more than one per square foot) than anywhere in the world. They eat seabird eggs and spread the seeds of non-native weeds around the island. More significantly, they attract a few migrating Burrowing Owls each fall. The owls, lost over the ocean, would normally stop on the island and then leave. But with the mice there, the owls stay and feast. When the winter rains come, the mouse population crashes and the owls begin to starve. Right about then, the declining Ashy Storm-Petrels begin returning to the island to nest. The owls catch them and stack them like cordwood. (In the most recent review, they were not listed an “endangered” based on the assumption that this project would be implemented.)

One thing to know about Ashy Storm-Petrels is that they are long-lived and slow-reproducing, like most seabirds. With the owls killing the adults, the storm-petrel population cannot recover.

Eventually, the owls starve to death. Then the mouse population rebounds in the spring and the cycle starts over, while the storm-petrel population spirals down. This happens every year on the Farallones.

Restoring the island thru mouse eradication

The plan is to eradicate the house mouse from Southeast Farallon Island, as we eradicated rats on Anacapa, and as has been done on over 600 islands worldwide.

Locations of all of the recorded eradications of invasive vertebrates from islands for which location data are available (n=664). 

The key is to get every last mouse—thousands of them. The only way to do this is to use rodenticide bait pellets. It will be done in the late fall, when the mouse population is at its low point, and when there are very few birds or mammals on the island. The few gulls present can be hazed with a laser (we’ve tested this). Any pellets that fall in the water will quickly decompose. On Anacapa, there were few secondary impacts; the benefits were far greater than we ever dreamed.

Scripps’s murrelet on Anacapa.

This project has been researched by dedicated biologists who know and love the island. We have explored all alternatives. (Contraceptives are not feasible. Introducing more raptors is NOT the answer.) We have researched possible harms and benefits. We’ve seen the amazing restoration of the ecosystem on Anacapa and on 600 islands worldwide, and we’ve worked with experts from New Zealand.


Here is a list of organizations and experts in support of the project:

  • National Audubon Society
  • Audubon California
  • American Bird Conservancy
  • BirdLife International
  • The Nature Conservancy
  • California Native Plant Society
  • California Invasive Plant Council
  • David Ainley; author of Seabirds of the Farallon Islands; Ashy Storm-Petrel species account in Birds of North America
  • Peter Pyle; Institute for Bird Populations; author of Identification Guide to North American Birds and over 100 journal articles
  • Peter Harrison; author of Seabirds: An Identification Guide.
  • Mark Rauzon, Marine Endeavors; author of Isles of Amnesia: The History, Geography, and Restoration of America’s Forgotten Pacific Islands.
  • Hadoram Shirihai, Tubenoses Project; author of A complete guide to Antarctic wildlife: the birds and marine mammals of the Antarctic continent and the Southern Ocean; Whales, dolphins and seals: A field guide to the marine mammals of the world; The Macmillan birder’s guide to European and Middle Eastern birds.
  • Debi Shearwater, Shearwater Journeys, 44 years of offshore experience; co-author of Distribution patterns and population size of the Ashy Storm-Petrel
  • Dianne Feinstein, US Senator
  • Point Blue Conservation Science (formerly Point Reyes Bird Observatory)
  • Institute for Bird Populations
  • Pacific Seabird Group
  • Agreement on the Conservation of Albatrosses and Petrels
  • Island Conservation 
  • Oikonos
  • California Academy of Sciences
  • California Institute of Environmental Studies
  • Oiled Wildlife Care Network
  • International Bird Rescue
  • Golden Gate Audubon Society
  • Marin Audubon Society
  • Monterey Audubon Society
  • San Diego Audubon Society
  • Sequoia Audubon Society
  • Marin County Supervisor
  • Santa Cruz County Supervisor
  • National Refuge Association
  • Save the Bay
  • Farallon Islands Foundation
  • Citizens Committee to Complete the Refuge
  • Coastal Conservation Action Lab
  • Freshwater Life
  • Marin Conservation League
  • Marine Endeavors
  • Natural Heritage Institute
  • South Georgia Heritage Trust

More details about the project and the public process

More details about the project, the process, and all relevant documents can be found here. The project will come before the California Coastal Commission on Dec 16, 2021. Letters to the Commission should be emailed to The deadline for letters is 5pm on Friday, December 10.

Related reports and videos

Here are some videos and reports about past similar projects:

Paper: The Global Islands Invasive Vertebrate Eradication Database: A tool to improve and facilitate restoration of island ecosystems

Article: 169 Islands that Offer Hope for Stemming the Extinction Crisis: Nearly 10% of island extinctions can be prevented through the eradication of invasive mammals on 169 islands

Anacapa Island Rat Eradication

Achieving Balance: Anacapa Island Ten Years After the Removal of the Black Rat (15 min)

Final Report: Responses by Breeding Xantus’s Murrelets Eight Years after Eradication of Black Rats from Anacapa Island, California  

All the reports on the Anacapa rat eradication

Short documentaries/reports of rodent eradications from islands around the world

Night Birds Returning: eradication of rats by Haida Nation and Parks Canada

The Rakiura Titi Islands Restoration Project: Community action to eradicate rats for ecological restoration and cultural wellbeing

Million Dollar Mouse: the eradication of mice from Antipodes Island

Macquarie Island Pest Eradication Project – documentary trailer

Rat Eradication – South Georgia Island

Eaten alive: Tristan Albatross chick massacred by invasive mice on Gough Island [WARNING: GRAPHIC]

Operation: Desecheo National Wildlife Refuge, Puerto Rico       

Southeast Farallon looking down from the summit. The steep hillside below hosts half the world’s population of Ashy Storm-Petrels.

Magic from Isla Mocha: Pink-footed Shearwater conservation thru soccer and children’s theatre

PFSH1Many think of Pink-footed Shearwaters as a relatively common bird on West Coast pelagic trips. I like to call them the “photographer’s shearwater” because they invariably offer great photo ops off the back corner of the boat. But they are considered endangered by Chile, threatened by Canada, and vulnerable by the International Union for Conservation of Nature (IUCN). They could easily be called the Chilean or even Isla Mocha Shearwater, as the entire world’s population comes from just three islands off the coast of Chile, 85% from Isla Mocha, and the remaining 15% from Santa Clara and Robinson Crusoe Islands in the Juan Fernandez group.

The very limited breeding range of the Pink-footed Shearwater is actually pretty typical of seabirds. To use some other West Coast species as examples, about half of the world’s Ashy Storm-Petrels come from one hillside on Southeast Farallon Island, 95% of the world’s Black-vented Shearwaters come from Isla Natividad off the Pacific Coast of Baja, and 99% of the world’s Heermann’s Gulls come from tiny Isla Rasa in the Sea of Cortez.


New research (Felis et al 2019), following 42 satellite-tagged birds, describes their seasonal movements from their breeding colonies in Chile. The new paper focused on threats at sea, especially bycatch by purse seine and drift net fisheries in Peru and Chile. CLICK TO ENLARGE.

And, typical of most seabirds, Pink-footed Shearwaters face some daunting challenges at their breeding colonies. At Santa Clara Island, non-native European rabbits denuded native vegetation, caused erosion, and kicked the shearwaters out of their burrows. When the rabbits were eradicated in 2003, the number of shearwater pairs went up 40% in three years. Native plant revegetation continues. On Robinson Crusoe Island, cattle trampled burrows, but a fence installed in 2011 now serves to keep them away from the colony. Shout out to Oikonos (a non-profit based in California, Hawaii, and Chile) and the Chilean national park service (called Corporacion Nacional Forestal or CONAF) for these projects.


But the real conservation challenge is at the shearwater’s main colony on Isla Mocha. Here, the local fishing community of 800 people are accustomed to harvesting shearwater chicks from their burrows. They’ve done so since the community began in the 1930s. And each pair lays only one egg a year. Chick harvesting has been illegal since 1998, but enforcement within a small community where everyone is friend or family is difficult.


Opening ceremonies of Copa Fardela soccer tournament.

Usually seabird restoration on breeding islands means restoring habitat or, more often, eradicating non-native rats, cats, mice, donkeys, you name it. But on Isla Mocha, Oikonos and CONAF have used another approach: outreach and education designed to reduce chick harvesting. The creative part is the strategy; the goal is for the islanders to identify with the shearwater as a symbol of their unique home, and thus want to protect them. Importantly, the project is led by a local Mochano, tapping into local values and local styles of communication. Thanks to the outreach efforts, school kids now flap their wings and enact dramas of the birds returning home. Adults play in the annual Copa Fardela (Shearwater Cup) soccer tournament.

This 48 minute video (in Spanish) documents the project. The Copa Fardela opening ceremonies, which features a children’s drama showing the shearwaters returning from the sea and producing a chick, begins around 42:00.

The fardela blanca, as they call it, is becoming their shearwater.


Three-acre beach restoration project produces first nesting Snowy Plovers in nearly 70 years


Pilot study area after three years of protection and restoration. Plant cover has gone from zero to 5% coverage, which offers enough cover for plover nests.

Sandy beach restoration is simple and effective. A three-acre pilot project at Santa Monica Beach by The Bay Foundation has lead to the first nesting by Snowy Plovers in Los Angeles region in nearly 70 years. This was in 2017. Since then, plovers have remained in the area but not yet re-nested.


This tiny project demonstrated “restore it and they will come.”

In fact, only two acres were actively restored thru not much more than a sand fence to build up sand hummocks and the distribution of native plant seeds to encourage dune vegetation. Add a key final ingredient: the absence of people and “beach grooming” (raking by trucks dragging large rakes). The third acre, on the ocean side of the restored section, was left un-groomed, a rarity in southern California. This leaves the “seaweed” (aka beach wrack), home to invertebrates and food to shorebirds. The cessation of beach grooming  has already been correlated with an increase in shorebird foraging.

Furthermore, a new native plant species, or possibly a rare variant, was discovered at the site, having germinated on its on. For a very detailed report on the project, see the project website.

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Snowy Plovers, a state and federally listed species, nest on sandy beaches, often putting them in conflict with human recreation.


A marsh in Richmond: what a restoration project taught me about racial bias, white privilege, and environmental justice

IMG_8286The people of Richmond did not like our choice for a restoration project; they wanted a different one. They called us racist. At first, we were perplexed. Eventually, I realized they were right.

As a natural resource economist for the California Department of Fish and Wildlife, it was my job to assess injuries to wildlife and habitat due to pollution events, and to seek compensation, thru restoration, to “make the public whole.” Working with partners from the US Fish and Wildlife Service, NOAA, and other state and federal agencies, we enjoyed our work— suing oil companies and using the recovered funds to do habitat restoration. We were “the trustees”; we represented the people and the natural resources and acted on their behalf. We were the Lorax; we spoke for the trees. We had been as innovative as we were successful, pioneering seabird restoration on breeding colonies in Canada, Alaska, Mexico, and even New Zealand to benefit bird species killed by oil spills in California. Those were the only places they nested, so we did what made the most biological sense.

In 2012 we began assessing damages to Castro Cove in San Pablo Bay near Richmond. It had been contaminated by oil, mercury, and lead associated with the adjacent Chevron refinery. To compensate for the injuries (in addition to cleaning up Castro Cove), we proposed to restore saltmarsh wetlands at Cullinan Ranch, part of San Pablo Bay National Wildlife Refuge, about ten miles to the north. We immediately met opposition from locals. They wanted the settlement funds to stay in Richmond; Cullinan Ranch was too far away.

We have project selection criteria set in federal regulations. Top of our list is always nexus— we aim to restore the same type of habitat and species that were injured. But there are also other things to consider: feasibility, partnering funds to make the project bigger, cost (bang for the buck), etc. When it came to evaluating restoration options, Richmond had little to offer. The refinery was merely one of several industrial or former industrial sites along their bay front. Contamination issues were everywhere. A poster child for environmental injustice, Richmond is also poor and predominantly non-white. We thought Cullinan Ranch was a good solution.

The people of Richmond wanted us to spend the funds restoring Breuner Marsh. This was a 238-acre parcel just north of Castro Cove wedged between the bay and the railroad tracks. Across the tracks was Parchester Village, a housing tract built after World War II to house African Americans enticed to move there and work in the nearby factories. It was one of the few places offering FHA home loans to non-whites. They came primarily from Louisiana, a land of marshes. They would cross the tracks and enjoy the wetlands as a place to hunt and fish. To this day, Parchester Village remains predominantly black. Whitney Dotson, and his father Reverend Dotson, have been fighting development proposals there, by a man named Breuner, for decades.

Initially, we, the natural resource trustees, fought the people of Parchester. The Cullinan project exceeded the Breuner project by most criteria. It was already part of a protected refuge. It had ten feet of elevation gain to buffer sea level rise. And the project, modifying the levee system, promised to restore 1500 acres; it had serious bang for the buck. And we asserted that ten miles away was no big deal.

But the distance was a big deal, and we didn’t understand why. I did not understand that other subcultures in the US don’t hop in their Prius and drive an hour to see a rare bird like me. They don’t throw their kayak on their Suburu and head for the boat launch. Nor were the people of Richmond, working two jobs and long shifts, going to drive to Cullinan, which had little parking and no bus service. They wanted to protect and restore their own marsh across the tracks from their neighborhood. They knew, better than we, that using our criteria, places like Marin County across the bay, one of the wealthiest counties in the nation, would win every time. No prior contamination? Check. Partnering funds? Lots. Contiguous with other protected areas? Of course.

When the people we are supposed to be compensating are complaining about our proposal, that’s a red flag that perhaps our criteria are biased, our evaluation is wrong, and that their values are not the same as our values. And they are the ones who matter. As trustees, we were supposed to ensure the compensation of the impacted people. We are obligated to see the world through their lens.


The $14 million dollar project has re-contoured the wetlands and planted native grasses, as well as extended the Bay Trail with a paved bike path, parking lot, and restrooms. When I visited recently, two Golden Eagles, normally rare next to the Bay, skirmished over a kill in the grasses. 

A similar conflict arose in Mississippi after the Deepwater Horizon oil spill. At a contentious public meeting between the predominantly African American public wanting one type of restoration and white agency scientists proposing another, one exasperated woman stood up and asked, “Why are you all white?” When the government officials told me about this, they were scoffing. But it’s a great question. We all know the answer. They got their positions in government because they had college degrees. This in turn was highly correlated with a good high school and a good neighborhood. The money that financed all that started with their parents or grandparents, who probably began accumulating their family’s wealth after a subsidized college degree and home loan thru the GI Bill, or an FHA home loan, or maybe even a free plot of Native land via the Homestead Act, all programs that built the white middle class—and largely excluded people of color. The odds of a black person qualifying for one of these government positions were slim. That’s why that panel of restoration experts was all white. And they brought their cultural values with them.

In the end, we caved in and split the funds between Cullinan and Breuner (begrudgingly). I went to the Breuner Marsh project dedication ceremony, which featured speeches by both Whitney Dotson and Representative George Miller. There I learned everything I should have known earlier. That the people of Parchester Village had been fighting to save that marsh for decades.

They have since renamed the marsh; it is now the Dotson Family Marsh.