US Fish and Wildlife proposes to aerial bomb 1.5 tons of rodenticide on the Farallon Islands to kill mice that do not harm birds, as explained in articles published earlier by Conservation Sense and Nonsense.  The California Coastal Commission declined to approve the project in 2019.  At the request of US Fish and Wildlife, the California Coastal Commission will reconsider the Farallon Islands project at their meeting on December 16, 2021.  It's time to make your opinion of this project known to the Coastal Commission.  The Environmental Impact Statement for the project explains the project and its anticipated impacts. 

Click on this pictures of the Farallon Islands to see a video prepared by the Ocean Foundation about the islands and the proposed project.

Below is my message to the Coastal Commission. Beyond Pesticides has also provided a sample comment letter that is available HERE.   Please consider sending your own comment to the Commission here: EORFC@coastal.ca.gov. The deadline to send a written comment is 5 pm, Friday, December 10, 2021.  You can also submit a request to speak on agenda item 11b at the meeting HERE.   The deadline to request to speak is 5 pm, Wednesday, December 15, 2021. 

Dear California Coastal Commission, 

Please take my comments into consideration when evaluating the proposed project on the Farallon Islands.  I hope the Coastal Commission will confirm their lack of support of the project at your December 2021 meeting.

Thank you for your consideration.

Public Comment on Farallon Islands project

I am opposed to the plans to aerial bomb rodenticides on the Farallon Islands to eradicate mice for several reasons:

  • The project admits that hundreds of non-target birds will be killed by the rodenticide, either directly or by eating poisoned mice.  In September 2020, California banned the use of the rodenticide that will be used by this project because of the deadly impact on non-target wildlife, yet an exemption was created that will enable its use by this project.  The promoters of this project cannot deny that hundreds, if not thousands of non-target animals will be killed by this project.  That outcome is now confirmed by California State Law and by similar projects elsewhere in the world.   
  • The EIS clearly states that mice are not harming birds or chicks, the claimed beneficiaries of this project.  The EIS clearly states that a small population of burrowing owls is blamed for eating birds and chicks of other bird species. Removing the owls from the Farallon Islands is the non-toxic solution to the perceived problem. Yet, "…translocation of burrowing owls in lieu of eradicating mice was not considered as an alternative." (pg 47)  The EIS then contradicts itself by offering translocation as mitigation for anticipated collateral bird mortality: "Migrant species including burrowing owls would be transported off the island released into suitable habitat on the mainland." (pg 73)  Translocation is possible, but eradicating non-native mice is clearly the objective, not protecting bird species.  The mice are prey to many bird species.  Their loss will harm birds, not help them.
  • The food web on the Farallon Islands has not been adequately studied.  The project plan reports that the mice are a source of food for burrowing owls.  However, the project plan has not identified all of the predators of the mice.  Therefore, the project has not evaluated the extent to which the entire food web would be disrupted by the elimination of a major source of prey for birds of prey.  All predators of the mice are at risk of eating the poisoned mice and being killed by the poison.  Details on that issue are provided below.

These are the inadequacies of the EIS for this project:

Resident Burrowing Owls should be removed from Farallon Islands

The owls are the predators of the ashy storm petrel, not the mice.  Therefore, the owls are the obvious target for removal.  Given their small number relative to the large population of mice, their removal would be easier and less deadly to every animal living on the islands. 

This strategy was successfully used by the National Park Service to save the endangered Channel Island Fox on the Channel Islands.  Golden Eagles were not considered "native" to the Channel Islands.  They arrived in the 1990s because of feral pigs and goats that had been introduced to the islands.  When NPS took over management of the islands, they removed the feral pigs and goats, but not the Golden Eagles.  Deprived of the food the eagles came for, the eagles turned to preying on the Channel Island Fox, nearly driving it to extinction.  From 1999 to 2006, the eagles were trapped and moved off the island: "In order to mitigate golden eagle predation on island foxes, The Santa Cruz Predatory Bird Research Group, with the support of the Park Service and The Nature Conservancy, relocated golden eagles to distant sites on the California mainland. A total of 44 golden eagles, including 10 eaglets born on the islands, were trapped and relocated, and monitoring indicates that none have returned." NPS considers the removal of eagles the primary factor in saving the Channel Island Fox from extinction.  The 44 birds that were removed were more than 4 times more numerous than the 8-10 burrowing owls on the Farallon Islands.  They are enormous carnivorous birds, compared to the pint-sized, ground-dwelling burrowing owls. 

Please note that the threat to the fox posed by Golden Eagles was created by the removal of the prey of the Golden Eagles without adequate analysis and understanding of the food web.  NPS should have predicted that the loss of the preferred prey of Golden Eagles would disrupt the food web in ways that could have been predicted.  Now other "experts" are poised to make a similar mistake at the expense of thousands of rare birds and marine mammals on the Farallons.

The Madrone Chapter of Audubon Society in Santa Rosa opposes this project and agrees that relocation of burrowing owls is "feasible and could be planned and carried out."

Disrupting the Food Web

The EIS has not adequately analyzed the food web on the Farallon Islands and has therefore not identified the environmental impact of eradicating an important source of food for the animals that live on the island. 

This depiction of a fresh-water aquatic food web is an example of the complexity of food webs.  The food web on the Farallon Islands is probably very different, but remains largely unknown because the EIS does not analyze it or describe it.  Source:  Creative Commons-Share Alike

According to the EIS, there are many birds of prey on the Farallon Islands, most migrating, but some resident:  falcons, hawks, kites, eagles, owls, and kestrels. Most of the migrating raptors are on the island in the fall, when the mouse population is at its peak.  The EIS acknowledges that the raptors probably eat mice on the island, but dismisses that as a significant issue. However, it would be a significant factor in evaluating environmental impact if migrating raptors compensate for the loss of mice as their prey by preying on birds or salamanders.  The EIS does not address the important question of what birds of prey will eat if mice are eradicated. 

Given that mice are expected to survive for 21 days after being poisoned, and the poison is expected to be effective for over 100 days, it is more likely that many birds of prey will be killed by eating poisoned dead or dying mice. The number of days the rodenticide is expected to be effective exceeds the known limits of hazing effectiveness. For that reason, the EIS says the project will "attempt" to capture raptors present on the island prior to and during bait application.  An unsuccessful "attempt" will result in the death of raptors.

There are also many animals living on the Farallons that could eat the poison or the poisoned mice, but not killed by the poison, such as invertebrates and Dungeness crabs.  Although they are not killed, they would be contaminated by the poison they eat and become killers of the animals that eat them, such as birds and marine mammals. 

The EIS states that many of the insects that live on the Farallons are detritivores that feed on decomposing carcasses, such as the poisoned mice.  Then they become killers of the warm-blooded animals that eat them.  The Farallon Islands are located within the Dungeness crab fishery.  If they are contaminated by poison pellets or fish, they could become killers throughout the fishery.  According to the EIS, "Adult crabs are opportunistic feeders, but prefer clams, fish, isopods and amphipods. Cannibalism is common. Several species of predators feed on Dungeness crabs, especially the pelagic larvae and small juveniles, including octopuses, larger crabs and predatory fish such as salmon, flatfishes, lingcod, cabezon and various rockfishes. They are numerous in offshore areas of the Gulf of the Farallones, and support one of the most productive fisheries in California."

A similar mistake was made by a rat eradication project on the Palmyra atoll.  The first attempt to eradicate the rats in 2002 failed partly because Palmyra's abundant land crabs outcompeted the rodents for the poisonous bait. The crabs' physiology allowed them to eat the poison—the anticoagulant brodifacoum—without ill effect.  The reason why this attempt failed was that the "experts" who designed this poison drop did not realize that the rats lived in the coconut palms and didn't spend much time on the ground.  In other words, the poison wasn't dropped where the rats lived.  The second drop was delivered to the crowns of the palms:  "The crowns became a convenient platform for stashing cotton gauze sacks of poison bait, delivered by workers firing slingshots or dangling from helicopters."  This project is now focused on eradicating 30,000 adult palms and over 2 million juvenile palms from Palmyra using herbicide.  These island eradications have repeatedly demonstrated that they are not successful and they ultimately put land managers on a perpetual pesticide treadmill.   The result is a poisoned environment that is dangerous to every living plant and animal on the island.

Ironically, the explosion of the mouse population on the Farallons was the unintended consequence of inadequate understanding of the food web:  "House mice and other animals such as cats and rabbits were introduced to the island when ships landed there in the 19th century. While the cats and rabbits have been removed, the mice population has exploded to an estimated 60,000, or about 500 mice per acre."  One of the primary predators of the mice was removed, which resulted in increased population of their prey, the mice.  Now USFWS proposes to eradicate the prey, which will have unintended consequences, such as the death of the predators who will eat the poisoned mice, or the predators of the mice eating bird eggs and chicks instead, or predators not having adequate food, or all of the above.   

Rodenticides are known killers of birds of prey

This article published by Beyond Pesticides explains how birds of prey are killed by rodenticides:  "While a rodent is likely to die from this poison, ingesting it also turns it into a sort of poison Trojan horse for any predator that may take advantage of its slow decline. An eagle that eats a poisoned rodent at the edge of death will be the next to succumb to the anticoagulant effects 'Humans need to understand that when those compounds get into the environment, they cause horrible damage to many species, including our national symbol, the bald eagle,'" said the scientist who conducted a study of eagle deaths that found: "'The vast majority of bald and golden eagles in the United States are contaminated with toxic anticoagulant rodenticides, according to research published earlier this month.'" We know that 46 bald eagles and over 420 seabirds were killed by the rat eradication attempt on Rat Island in Alaska, but we don't know how many more were contaminated with rodenticide and are handicapped by sub-lethal effects. 

Source: Beyond Pesticides

Temporary Results

One of many reasons the mouse eradication project on the Farallon Islands is controversial is that similar projects all over the world are not successful.  Some are not successful in the short run and are immediately done again. Lehua is one of the Hawaiian Islands on which extermination was attempted and failed.  An evaluation of that attempt was published in 2011 to determine the cause of the failure so that a subsequent attempt would be more successful.  That evaluation included this report on the success of similar attempts all over the world:  "An analysis of 206 previous eradication attempts against five species of rodents on islands using brodifacoum or diphacinone is presented in an appendix to this report. For all methods, 19.6% of 184 attempts using brodifacoum failed, while 31.8% of 22 attempts using diphacinone failed." The Farallons project plans to use brodifacoum. 

Some are not successful in the long run.  Rodenticides were aerial bombed on the Lord Howe Islands in Australia in 2019 at a cost of $16 million. Two years later, two rats (one male and one pregnant female) have been found.  Genetic tests will determine if they arrived from elsewhere or are descendants of the original population. An article in The Guardian explains the elaborate effort on Lord Howe to find new rats and exterminate them.  This strategy might work on an inhabited island, such as Lord Howe, but it is not an effective strategy on the Farallons because it is not inhabited, has only occasional visitors, and its steep, rocky terrain is not easily monitored.  New mice or rats could be undetected on the Farallons long before anyone would know it. 

This is an example of one of the fundamental truths of the "restoration" industry:  The work is NEVER done.  It must be done repeatedly.  The cost is daunting, the collateral damage to non-target animals often unacceptable, the results only temporary.  The cost-benefit ratio is unfavorable.

Ethical considerations

For the record, I would like to clearly state my objection to the Farallons project.  I consider it unethical to kill one species of animal based on a presumed benefit to another animal species.  In this case, the chosen scapegoat is considered a non-native animal that has lived on the Farallon Islands for nearly 200 years and is therefore fully integrated into the food web.  There are millions of sea birds and mammals living on the Farallons.  They are the best testament to the fact that mice have not been harmful to birds and other animals on the Farallons.

Hundreds of non-target animals will be killed by this project because of the toxicity of the rodenticide and the random manner in which it will be applied on the island.  The project will clearly do a great deal of harm to all life on the Farallons and its benefits are obscure at best. Please do not endorse this pointless, deadly project.