Island eradications in the Bay Area rear their ugly head again

The Farallon Islands are a National Wildlife Sanctuary just 27 miles off the coast of San Francisco, where millions of birds and marine animals are legally protected.  Plans of the US Fish and Wildlife Service (USFWS) to aerial bomb 1.3 metric tons of rodenticide to kill mice on the Farallon Islands originated over 5 years ago.

Farallon Islands, NOAA
Farallon Islands, NOAA

The stated purpose of this project was to protect the ashy storm petrel, a legally protected species of concern.  The mice are not a direct threat to the petrel.  Rather, USFWS claims that another legally protected species of concern, the burrowing owl, eats the chicks of the petrel when the population of mice dwindles.  Because the average population of burrowing owls on the Farallons is said to be only 6 burrowing owls, the scale of their predation of petrel chicks seems minimal given that their preferred prey is mice.  USFWS theorizes that if the mice are killed, the burrowing owls will leave the Farallons.  This rather fanciful scenario is less credible than the more likely outcome that the burrowing owls will either be killed by the poison or eat yet more petrel chicks if their mice diet is eliminated.

Aside from the convoluted and questionable rationale for this project, the main concern is the anticipated collateral damage caused by aerial bombing huge quantities of rodenticide (brodifacoum).  The planned rodenticide is an anti-coagulant that is highly persistent and causes all vertebrate animals (mammals, reptiles, birds, fish, etc.) to bleed to death.  Death is not quick; the poisoned animals stumble around before dying and are easy prey for other animals that are then killed by the poison.  Dead, poisoned mice are equally attractive food for some birds.  The poison pellets are also as appealing to other animals as to mice.  Even the supporters of this project readily admit that many animals other than mice are likely to be killed directly by the rodenticide or as secondary victims.  “Stuff happens,” they say with a shrug.

The author of the Environmental Impact Statement is the same organization—Island Conservation—that will implement the project, if and when it is approved.  This conflict of interest seems one of many unwise decisions made by US Fish and Wildlife Service.

The opposition to this project has been loud and clear.  Maggie Sergio, who reported this project on Huffington Post, published a petition in opposition to the project that was signed by over 32,000 people.  And many prestigious organizations including the EPA, American Bird Conservancy, City of San Francisco, The Ocean Foundation, and several retired USFWS scientists, have also criticized the project.  Yet, five years later approval of the Revised Draft Environmental Impact Statement is still pending. Theoretically this project is still alive.

Farallons project comes to life again

The Farallons project has always seemed to us so ill-advised and misconceived that we could not believe it would materialize.  We have therefore not covered it since 2014 when we republished Maggie Sergio’s Huffington Post article and asked people to sign her petition.

Unfortunately, we were under-estimating the power and influence of the supporters of this project.  Bay Nature, a local nature magazine, recently published an article about the Farallons project and island eradications in general.  That article seems to assume there is consensus that mice must be eradicated on the Farallons and that the only question is the method that will be used (more about Bay Nature’s proposed method later).  And the California Invasive Plant Council (Cal-IPC) has published an endorsement of island eradications—including the Farallons—in its most recent newsletter (available here: Cal-IPCNews_Summer2016).  Cal-IPC’s preferred strategy for eradications is aerial application of rodenticide.  Therefore, our concern about the proposed Farallons project has once again been elevated to crisis levels.  When two local organizations, which claim to advocate for conservation endorse the Farallons project, we must take it seriously.

History of island eradications

Since learning about plans to eradicate mice using rodenticides, we have learned that the practice originated in New Zealand, where poison applications began over 60 years ago to kill a wide range of non-native animals.  Bill Benfield tells the entire story of eradications in New Zealand in his book, At War With Nature.  (1) We have relied on that valuable resource for this article.  That history is relevant to us because there are some striking similarities between the North American and New Zealand versions of invasion biology, the ideology that drives eradication attempts in North America and New Zealand.

The moa was a huge flightless bird that was hunted to extinction by Polynesians when they occupied New Zealand.
The moa was a huge flightless bird that was hunted to extinction by Polynesians when they occupied New Zealand.

Humans occupied New Zealand more recently than their arrival in North America.  Prior to their arrival, New Zealand was inhabited by many flightless birds that were successful because they had no predators.  The moa was the largest of those birds.  Although it has been extinct for hundreds of years, palaeontologists tell us the moa was about 12 feet tall and weighed about 500 pounds.  It was easy prey for the first humans who arrived in New Zealand about 800 hundred years ago from Polynesian islands.  As most sea-faring humans do, they unintentionally brought with them a species of rat, the kiore.

The climate of New Zealand is much colder than the Polynesian home of the first humans and their agriculture was not well suited to the climate of their new home.  The moa quickly became the main source of food for the humans. The moa were rapidly driven to extinction by hunting, which forced the humans to retreat to the northern end of New Zealand where the climate is milder and their agriculture was more successful.

Although there is some debate about the size and range of the moa population, Dr. Graeme Caughley reported that the moa population was very large and widely spread, based on a calculation of the available sustainable bio-mass.  He believes moa populations existed in all vegetation types, including forests where they would have browsed the forests.  Intense browsing of the forests would have encouraged the growth of the slower growing and unpalatable browse-resistant trees that became the forest giants. The faster growing species of trees were the palatable browse- tolerant species that were held back by browse, allowing the growth of slower growing trees that would in time become the forest giants.  The moa also would have spread the seeds of the trees they ate and inhibited the growth of an understory.  In other words, the forest that humans found when they arrived in New Zealand around 1200 AD was adapted to the big population of moa.

In the absence of moa the composition of the forest quickly responded to the absence of browsing.  Fast growing trees that were formerly held back by browse were no longer at a disadvantage compared to slow growing and unpalatable browse-resistant trees; the forest under-story became denser.  The composition of the forest that was found by Europeans when they arrived in New Zealand several hundred years later was in transition. 

Forest in New Zealand
Forest in New Zealand

The first humans on New Zealand did not have a written language.  The landscape they found when they arrived is not recorded in history and is only known to the extent that archaeological and paleontological evidence is accurately used to reconstruct it.  As all human science does, these disciplines are continually evolving and therefore did not inform the earliest versions of ecology that spawned the eradication movement on New Zealand.  In other words, the forest found by Europeans when they arrived in New Zealand is still considered the pristine ideal that ecologists wish to replicate.  In fact, that landscape was just as modified by human habitation as any modern, “novel” ecosystem.

This fantasy of a pristine, pre-human landscape is similar to the fantasy in North America that the landscape found by Europeans when they arrived on the East Coast in the 16th century and the West Coast in the 18th Century was the “natural” landscape, unaltered by humans.  They are just as mistaken in that assumption as they are in New Zealand. Native Americans actively managed the landscape to serve their horticultural and cultural needs.  The consequences of that fantasy have been just as deadly and destructive in New Zealand as they have been here in California.

The deadly crusade in New Zealand

Europeans brought many animals with them to New Zealand, just as they did to North America.  They brought both domesticated animals such as sheep and wild animals such as deer that they could hunt.  The deer browse the forest, just as they do here, and the impact they have on the forest is similar to the impact moa had on the forest. The deer and other browsers are the functional substitute for the extinct moa. Fast growing palatable species of trees are disadvantaged by browsing and these are the trees that early ecologists considered the “natural” forests of New Zealand because they were the trees that were found when Europeans arrived. 

1080 Poison Warning in New Zealand
1080 Poison Warning in New Zealand
Deer poisoned by 1080. Graff Brothers, New Zealand
Graf Brothers, New Zealand

Hence, aerial poisoning of the land began over 60 years ago to kill all browsing animals in New Zealand except domesticated animals kept behind fences.  Smaller non-native animals such as possum are also targets for eradication because they are assumed to be predators of the few flightless birds that remain in New Zealand.  This accusation is refuted by Bill Benfield who tells us that possum are primarily vegetarians and that a study of the contents of possum stomachs found no evidence of bird predation.  Possum are also accused of being carriers of bovine TB, a disease that infects domesticated animals.  However, recent laboratory tests find no evidence that possum are infected with bovine TB, beyond minute levels.  In any case, the possum population is small because it is a species that rears only one pup per year, so its population would grow only slowly if they weren’t being exterminated in New Zealand.

The killing fields

A different poison is used in New Zealand–called Compound 1080–that operates in a different way than anti-coagulant rodenticide.  It kills indiscriminately any life form that requires oxygen.  It was developed as an insecticide in Europe, and was initially used in the US where it was briefly used to kill coyotes and other wildlife considered inconvenient predators until its use was severely restricted because of its extreme toxicity.  It is entirely banned in California, which is why our local version of island eradications use anti-coagulant rodenticide instead of 1080.

Graff Brothers DVD available on Amazon
Graf Brothers DVD available on Amazon

1080 is a slow, grisly killer of EVERYTHING: insects, fish, mammals, birds, amphibians, etc.  It is just as likely to kill native animals as non-native animals and it does.  This indiscriminate killing of every living thing in New Zealand was described in chilling detail by Elizabeth Kolbert in the New Yorker.  It is also visible in the videos of the Graf brothers for those with a strong stomach.  HERE is one of many of their videos.

Exporting death

We could turn a blind eye to what is happening in New Zealand if this strategy were not being exported all over the “civilized” world.  Amazingly, such island eradications have happened in many places and are being proposed in many places where local resistance is trying to prevent them from being implemented.  What have we learned from the projects that have been done?  The record is sketchy because very little after-the-fact monitoring of completed projects has been done.  What we DO know, suggests that it is not in the interests of the promoters of these projects to monitor the outcome of their projects because the results are consistently deadly and unsuccessful.

Killing one species of plant or animal does not restore an ecosystem

Readers of Million Trees will not be surprised to learn that killing one species does not magically “restore” an ecosystem to some historic ideal because ecosystems are very complex and their occupants live in communities with many, complex interactions that are not perfectly understood by humans, even humans calling themselves invasion biologists.

One study of islands off the coast of New Zealand compared the vegetation structure and ecosystems of three island systems: islands that never had rats, islands with rats, and islands on which rats had been “controlled.” They concluded that, “The extent to which structure and function of islands where rats have been eradicated will converge on uninvaded islands remains unclear…Since most impacts of rats were mediated through seabird density, the removal of rats without seabird recolonization is unlikely to result in a reversal of these processes. Even if seabirds return, a novel plant community may emerge.” (2)

There are many other factors that prevent the re-creation of historical landscapes, such as climate change.  There are undoubtedly many factors that are not known to us, which prevents us from “fixing” something we do not understand.  In any case, many of us don’t consider it necessary to “fix” something that we don’t consider broken.

Collateral damage and incompetent execution

In those few cases when after-the-fact monitoring was done, there is considerable evidence that many non-target animals were killed and the water was polluted.

In the case of Rat Island, off the coast of Alaska, no monitoring was planned after the aerial bombing of 46 metric tons of anti-coagulant rodenticide to kill rats.  However, neighbors of Rat Island demanded an investigation when they saw dead birds and animals floating in the vicinity of the island after the project was done.  That investigation (available HERE) was done by USFWS Law Enforcement.  The investigation found that the manufacturer’s recommendations regarding dosage were exceeded, that instructions to collect dead rats so they would not be eaten by birds were not followed, and that hundreds of birds died, including many legally protected bald eagles.  The investigation was not done until 7 months after the project was completed.  We should assume that the number of dead animals found would have been greater if the investigation had been done promptly after the project was completed.

Palmyra Atoll. USFWS
Palmyra Atoll. USFWS

In the case of Palmyra Island, off the coast of Hawaii, the scientific study conducted after the aerial bombing of rodenticides reported, “We documented brodifacoum [rodenticide] residues in soil, water, and biota, and documented mortality of non-target organisms. Some bait (14–19% of the target application rate) entered the marine environment to distances 7 m from the shore. After the application commenced, carcasses of 84 animals representing 15 species of birds, fish, reptiles and invertebrates were collected opportunistically as potential non-target mortalities. In addition, fish, reptiles, and invertebrates were systematically collected for residue analysis. Brodifacoum residues were detected in most (84.3%) of the animal samples analyzed. Although detection of residues in samples was anticipated, the extent and concentrations in many parts of the food web were greater than expected.” (3)

The rats return

The most damning evidence of all is that after killing untold numbers of animals, including those not meant to be killed, and poisoning the environment with a deadly toxin that bioaccumulates and persists in our bodies, the rat population often returns to pre-project levels within a few years. 

Henderson atoll in the Pacific is an example of such a failure.  Eighty tons of rodenticide pellets were aerial bombed on Henderson in 2011.  Apparently, at least two rats survived, one presumably male and one presumably female.  Within a few years the rat population had returned to pre-projects levels of 50,000 to 100,000 rats.

The rats were said to have been introduced to Henderson over 800 years ago.  Surely they had reached some balance between population size and available food sources.  Rats are an ancient species that would not be here if they completely wiped out their food sources.  Rat population growth is modulated by available food sources.  Hence, when almost completely eradicated, the rats rapidly reproduced back to equilibrium with food sources.

Claims that the Henderson project was urgently needed to prevent the extinction of a bird species with which rats had co-existed for over 800 years were bogus.  If rats had not exterminated the birds within 800 years, they weren’t likely to do so before this pointless project killed tens of thousands of animals, probably including many birds.

Like most “restoration” projects, claims are made about a conservation crisis that is often just an emotional appeal without any scientific basis.  Money is raised and spent in response to these fabricated crises and many “non-profit,” untaxed organizations subsist on these campaigns.  In the case of New Zealand, the poison they are using is manufactured by the government, creating an unholy financial incentive for these eradication projects. 

The failure of the extermination attempt on Henderson is not an isolated incident.  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.”  Brodifacoum and diphacinone are both anti-coagulant rodenticides.  Diphacinone is considered less toxic and less persistent than brodifacoum.

The silver bullet?

The “restoration” industry is meeting with a great deal of public opposition.  Because some of the opposition is based on concerns about polluting the environment with pesticides–such as herbicides used to kill plants and rodenticides used to kill animals–the “restoration” industry is looking for a less controversial method of accomplishing their deadly goals.

This brings us back to the recently published article in Bay Nature about island eradications.  The article informs us that a genetic modification of mice is now being developed, which would drive that species to extinction by ensuring that all off-spring would be males, thereby ending reproduction of the species. This method has a seductive appeal because it would not poison the environment.  However, it is an insidious proposal and we will let some of the commenters on the Bay Nature article tell us why, because some of them sound like knowledgeable scientists with ethical concerns:

  • Has the conservation movement lost its mind? Gene drive is unsafe, unproven and unethical. It is the most insane idea I have heard of in my 20 years reporting on genetic engineering. And it is presented here with no critical analysis, scientific, ethical, or environmental. I have spent my life in conservation and want to do all I can for to stop extinction but using extinction to stop extinction? Gene Drive is a technology that says one species (us) gets to decide which other species live or die. This is not populations that will be eradicated, it is aimed at an entire species. Who likes pests like rats or mosquitoes? But think. What’s next? Could this be a cynical ploy to use conservation to test this dangerous technology? Because once accepted it can then be used for many far less “acceptable purposes – such as a bioweapon.” – Claire Cummings
  • “The Alison Hawkes article reminds me (as a Kiwi i.e. New Zealander) of the mad and dangerously flawed science that is rampant in New Zealand. And just because it’s labelled science, don’t unquestioningly believe in it. Scientists here have to operate under a commissioned, paid science regime. The science becomes warped and inaccurate. Too often pseudo science (e.g. New Zealand’s destructive 1080 programme) intrudes and disrupts the natural ecosystem with disastrous consequences.  In NZ, objectives are often founded on unrealistic goals, i.e. turning NZ ‘s ecological clock back to 500AD. That’s impossible while humans and mad science remain.” – Tony Orman
  • It is extremely disappointing to see Bay Nature carry an article on such a controversial and risky plan with such lack of balance or even basic journalistic diligence. Contrary to the impression presented here CRISPR CAS9 gene drives are highly immature – it being barely 15 months since the first proof of principle of the ‘mutagenic chain reaction’s shown and they already have generated enormous controversy including a 200 page National Academy of Sciences Study that warned against open release and growing discussions at the Convention on Biological Diversity where there have been strong calls for a moratorium on this risky new technology.” – Jim Thomas

It seems that destructive “restoration” techniques are developing faster than human common sense can keep up with.  What can we do to slow it down?  What can we do to prevent the pointless poisoning of our environment and the needless killing of defenseless animals and harmless plants?  I don’t know the answer, but I will keep asking the questions and I hope my readers will as well. 

Update:  The Final Environmental Impact Statement for the mouse eradication project on the Farallon Islands was published on March 15, 2019.  The Final Environmental Impact Statement recommends the original plan as the “preferred alternative.”  In other words, despite intense opposition to this plan, its implementation is now eminent. 

No public comments are allowed on a Final Environmental Impact Statement, so there’s nothing further we can say about what seems to be an unnatural disaster in the making.  At this stage of a project, lawsuits are the only way to stop it.  I don’t know if anyone is willing and able to sue. 


  1. William F Benfield, At War With Nature: Corporate Conservation and the Industry of Extinction, 2015, available on Amazon.com in digital format
  2. Christa Mulder et.al., “Direct and indirect effects of rats: does rat eradication restore ecosystem functioning of New Zealand seabird islands?” Biological Invasions, August 2009, 1671-1688
  3. William Pitt, et. al., “Non-target species mortality and the measurement of brodifacoum rodenticide residues after a rat (Rattus rattus) eradication on Palmyra Atoll, tropical Pacific,” Biological Conservation, May 2015, 36-46

The futility of eradicating non-native species

We tend to focus on the native plant “restorations” in our neighborhood, but we should not lose track of the fact that similar efforts are taking place all over the world.  The native plant movement is international and if it loses momentum, we should expect to see loss of support for its destructive projects elsewhere.  So, today we will tell our readers about several recent developments that suggest that scientists all over the world are having second thoughts about invasion biology, which is the scientific underpinning of the native plant movement. 

Second Thoughts:  The Hawaiian Case

We have reported to our readers about the many “restoration” projects in Hawaii.  There is some logic to focusing such efforts on islands, because they are the places most vulnerable to the loss of native species attributed to introduced species and theoretically they are also the places where re-invasion should be easiest to control.

Scientists have recently published the results of a ten-year effort to return an “invaded” forest to its native origins.  They spent about 5 years clearing the forest of all non-natives.  They planted the scorched earth with natives and then they walked away from it to observe the long-term sustainability of their effort.  Five years later they report that the composition of the forest—with respect to its nativity—has essentially returned to its original state.

They tested several hypotheses while observing the changes in the forest during the second half of the project.  Conventional wisdom had been that the more densely natives occupied the ground, the less vulnerable it would be to re-invasion.  Much to their surprise, this was not the outcome of their experiment.  The more densely natives occupied the ground, the greater the population of non-natives in the final analysis.  They conclude that the same conditions which encouraged the growth of native plants were equally beneficial to the growth of non-native plants.

This study was conducted by the US Forest Service.  We hope they learned something from this experience.  Specifically, we hope that the US Forest Service now understands that native plant “restorations” are not a one-shot deal.  They are a permanent commitment to garden that restoration with the same amount of effort.  That’s why scientists—such as Professors Arthur Shapiro and Peter Del Tredici—tell us that large scale projects are not sustainable in the long term.  A small scale native plant garden as an historical illustration is a worthwhile effort.  Gardening our vast public lands is like “plowing the sea,” as Professor Shapiro told us recently.

Second Thoughts:  The New Zealand Case

New Zealand has made herculean efforts to save its native species from “invasions” by non-native species:  “New Zealand is a very weedy country.  Indigenous plant species are matched in number by naturalized exotic species and about 20 new invaders are discovered each year.  Thus, a weed eradication program has been under way for the past 10 years, but eradicating an unwanted plant species is much more difficult than it might seem.” (1)

Eradicating yellow tree lupin, New Zealand Dept of Conservation

How successful have these efforts been?  According to a recent study, they have had very little success:  “The current issue of the journal Invasive Plant Science and Management assesses the progress of 111 weed eradication programs carried out by New Zealand’s Department of Conservation.  Only four of these programs have met with success, while 21 have been discontinued and the rest remain an ongoing challenge.”

The report concludes, “After a decade, New Zealand’s weed eradication strategy has yet to yield significant results.”  Anyone who has been watching similar efforts all over the San Francisco Bay Area will not be the least bit surprised by this conclusion.  With the exception of small gardens which are irrigated and intensively gardened, these projects are weedy messes, usually behind fences.

Second Thoughts:  The Australian Case

Scotia Sanctuary, Australia

Emma Marris interviewed the manager of one of many “restoration” projects in Australia for her book, Rambunctious Garden.  He told her about the 18 month process of killing all non-native animals in a 15-square mile sanctuary enclosed by a prison-like fence, “sturdy, tall, and electrified.”  (This was half of the Scotia Sanctuary)

“He was able to shoot out the goats in a matter of days.  Rabbits were harder…he put out carrot bait…the rabbits…would learn to trust the new food source…[then] the carrots would be poisoned…[He] repeated this routine three times, running through 12,500 pounds of carrots…For each fox, he learned its habits and was eventually able to find perfect places to trap or poison them.  He also trapped cats…The key to making it work, he says, was ‘perseverance, perseverance, perseverance.’” (2)

It was necessary to kill all the non-native animals before taking on the more difficult task of returning the land to native plants because of the interaction between the plants and animals.  The non-native animals are considered a continuing and permanent threat to the sanctuary.  The expectation is that this 250 acre restoration will require human intervention indefinitely into the future.

Australia is a huge place, so the prospect of this labor-intensive process being replicated on a nationwide basis is absurd.  Therefore, it seems inevitable that Australian scientists would begin to question the efficacy of such efforts. 

Just two months ago, an Australian scientist, Angela Moles, gave a TED (Technology, Entertainment, and Design) presentation suggesting that it is time to grant Australian citizenship to introduced species.  Click here to see the video.

Her reasoning is based on the relatively new understanding of the speed with which evolution occurs.  Her laboratory used the collection of a university herbarium to measure the changes in the plants that were introduced to Australia.  The herbarium had samples of the same species of plants collected over a 60 year period from the same location.  They found that the plants had changed in significant ways.  In a sense, they were becoming Australian plants in response to the biotic (other plants and animals) and abiotic (climate, soil, etc) conditions of their new home.  She predicted that if they weren’t yet genetically distinct from their ancestors, they soon would be.   In other words, they are becoming distinct, new species…..Australian species.

She showed a slide of her son who is a 2nd generation Australian.  He is considered an Australian by law and custom.  Then she showed a slide of clover which has changed significantly since its introduction.  After 130 generations, it is still not considered Australian.  After showing a few of the massive eradication projects and describing the scale and futility of those efforts, she suggested that it is long past time to accept the clover and other introduced species as Australian.

And, of course, we agree.  Let us abandon the destructive and futile war on non-native species.  The sooner we do, the less damage will be done to the environment and to the animals that live in it, including us.  

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(1)    “Eradicating Weed Species in New Zealand Poses a Larger Challenge Than Expected,” Science Daily, July 21, 2012

(2)    Emma Marris, Rambunctious Garden, Bloomsbury, 2011