December 2021 – Conservation Sense and Nonsense

When ideas remain unexamined and unchallenged, they intimidate ©

My last article of the year is a guest post by Marlene A. Condon, the author/photographer of The Nature-friendly Garden: Creating a Backyard Haven for Plants, Wildlife, and People (Stackpole Books; information available HERE.) You can read her blog In Defense of Nature.

Merry Christmas !

Million Trees

A birds-eye view of the University of Virginia (UHall seen in first photo) in Charlottesville, Virginia, makes clear that there are plenty of native trees to be found in developed areas.

The novelist E. L. Doctorow, in a 1989 conversation with PBS journalist Bill Moyers, said, “When ideas go unexamined and unchallenged for a long enough time, they become mythological and very, very powerful. They create conformity. They intimidate.”

He could have been speaking about the current environmental narrative regarding so-called invasive plants. Anyone who speaks out feels the wrath of the folks pushing their fictional environmental manifesto; I’ve lost jobs because of these people.

Most neo-scientists and -environmentalists, having arrived late to the party, have no clue as to why some alien plants exist in profusion along roadways, in former farm fields, and along trails in forests. The popular notion that native plants would otherwise be filling those areas is easily accepted by people who don’t possess knowledge of soil science, or who lack experience with gardening and/or closely observing the natural progression of plants in unmanaged, disturbed areas.

Knowing the prior history of the land is essential to understanding why particular nonnative plants fill some areas. Road building discomposes soil. Trail development/use and cows/farming-equipment moving over the land compact soil. Only “colonizer plants”—those capable of thriving under the altered and nutrient-poor conditions of these sites—can grow there.

Usually such areas, after many years, support a mix of native and nonnative pioneers, but sometimes alien plants outnumber the natives because they are best suited to the constraints imposed by the physical attributes of the site. Anyone (no Ph.D. required) can verify this statement by taking the time to observe the progression of plants in an area not revegetated by people. Doing so would make clear that alien plants do not “push out” native plants by “invading” and “taking over”, but rather, they fill disrupted areas where few native plants can successfully grow.

Yet, the desire by scientists and environmentalists is so great to get folks to remove supposedly invasive plants from the environment that we now have tall tales being spread. Herewith a sampling of some of the most egregiously untrue declarations regarding alien plants.

Johnny Randall, Director of Conservation Programs at the North Carolina Botanical Garden (University of North Carolina at Chapel Hill) wrote a New Hope [North Carolina] Audubon blog post called “Invasive Plants Are NOT for the Birds.”

He writes that, “The scientific literature on invasive plants and bird-dispersal is moderate but growing, and almost all of the research warns that this is a serious and multi-layered phenomenon. First off – birds either do not discriminate between native and invasive plants or often prefer invasives over natives. One reason for this is that a large proportion of invasives are high in carbohydrates, whereas the natives are often higher in protein and lipids/fats. Birds are consequently (pardon the analogy) choosing candy bars over cheeseburgers, which could affect bird nutrition, particularly during fall migration”.

The suggestion that birds are choosing “autumn olive berries [that] are sugary sweet treats, the junk food of the bird diet” is echoed by many people. This quote, from a letter to the editor of The Crozet Gazette by Susan A. Roth, William Hamersky, and Manuel T. Lerdau, Ph.D., is supposedly based upon a study published by the Wilson Journal of Ornithology in March, 2007, entitled “Fruit Quality and Consumption by Songbirds during Autumn Migration”.

Yet this study states that “Most common fruits on Block Island [where the study took place in Rhode Island] contained primarily carbohydrates…and little protein…and fat.” As the research paper’s authors were mainly speaking of native plants, this statement directly contradicts that of Mr. Randall that natives are often higher in proteins and fats than so-called invasives.

Additionally, the research paper’s authors state that “fruit selection by birds on Block Island was not simply related to differences in macronutrient composition between fruits…studies of wild and captive songbirds have shown that some species preferentially select high-fat fruits…or high-sugar fruits…”, which hardly implies that Autumn Olive fruits are a necessarily inferior food choice, as declared by Roth, et al.

A variety of foods exists to serve a variety of purposes. Turning sugar into something “bad” for birds comes as a result, perhaps, of this same application to human nutrition. But sugar is not in and of itself, “bad”. A runner in need of glucose who eats some jelly beans gets a quick burst of energy to continue exercising. There’s absolutely nothing wrong with that.

Sugar is only a problem if it’s eaten in excess, as might be done by children. But birds are not children; if they feel the need for protein and fat, they will search for insects and fruits that offer what they need.

Furthermore, Director Randall wrote that “Researchers have also shown that many invasive plants have fruits that persist longer than do native plant fruits into the fall and winter. The invasives are therefore available when our natives are not.”

In a world of disappearing habitat for wildlife because of human development, the fact that fruits on invasive plants are available when native-plant fruits are depleted should be seen as a positive rather than a negative.

Charlottesville, Virginia, residential area, has so many trees that you can’t see the roadways interspersed among them. In other words, insects and birds aren’t disappearing because alien plants have replaced native trees.

“Recent research published by Narango et al., in the October 22, 2018, issue of the Proceedings of the National Academy of Science demonstrates that native plants are best for birds. The research showed that yards landscaped with the usual garden center plants, which are mostly nonnative ornamentals, could not support a stable population of chickadees. Yards where native plants composed at least 70 percent of the plantings were able to do so. This is because native plants host more insects than non-natives and therefore provide the necessary high-protein food that birds need to feed their chicks.” [from a letter to the editor of The Crozet Gazette by Susan A. Roth, William Hamersky, and Manuel T. Lerdau, Ph.D.]

Narango’s study cannot be generalized to all birds, although many people have made the mistake of claiming it can. This study applies only to chickadees and certain other birds that inhabit forest because such species are dependent upon the native plants (trees) that comprise our forestland. In other words, if you want forest birds to reproduce in your yard, your yard must be forest. For a fuller explanation, please read “Chickadee Chicanery” at In Defense of Nature.

“These invasive species not only impact our forests, wetlands and streams, but also our economy, health and safety. They kill the trees that shade our homes and that our kids play hide-and-seek around. They increase the presence of other disease-spreading species like ticks. They diminish visibility along trails where safety is important”. [quote from an article from the Central Ohio Partnership for Regional Invasive Species Management at a Nature Conservancy-sponsored website]

The only “forests” where you will see alien-plant species are those that are either managed improperly (overly thinned and thus allowing too much sunlight to reach the ground under the trees) or those that are actually “woods” in the process of succession (transforming from a field to a forest that has not yet reached maturity). “Invasive” plant species are sun-loving and therefore do not inhabit shady mature forests.

As for killing trees, if “they” refers to vines (a common complaint in the eastern U.S.) one must ask, why was the homeowner unable (or unwilling) to keep a vine from killing a tree in his yard that his “kids play hide-and-seek around”? However, if “they” refers to nonnative animals and/or diseases killing trees, that is a different situation altogether, which is not the point of this article. It’s unfortunate the writer did not make clear what “they” referred to. As far as I can tell, there’s no proof that “invasive” plants, in general—as stated above—increase the presence of organisms such as ticks. A study published in Environmental Entomology

purportedly shows that barberry-infested plots support more mice and thus ticks than plots in wooded areas with no barberry.

However, the “no barberry” plots were severely browsed by deer and thus “little understory vegetation was present.” In other words, these scientists compared two completely different habitats, which explains the greater number of ticks in the shrubby (Japanese Barberry) area that provided “questing habitat [for] blacklegged ticks [whereas] little other suitable vegetation exist[ed] in [the] severely browsed forests.”

“Questing habitat” refers to plants upon which ticks can wait at the appropriate height to grab onto an animal that comes by. Obviously, ticks are not going to be found in an area with little understory vegetation as they have nowhere to sit and wait for their quarry.

And we’re to believe “invasive” plants diminish visibility along trails, and native plants don’t? It sounds more like the folks who are supposed to be maintaining the trails have been derelict in their duties!

It’s clear that scientists and journalists are doing everything they can to assure that government and the general public view so-called invasive plants in a negative light. Yet, to my knowledge, no study condemning “invasive plants” exists that has the least bit of merit.

Marlene A. Condon

Addendum by Million Trees

FUZZ: Fatal encounters of animals with humans

In Fuzz, Mary Roach treats a serious subject with a light touch, intended to entertain. Whether you are amused or horrified, Fuzz will inform you of the fatal consequences of animals threatening or inconveniencing humans. In every case, choices made by humans are the cause of these interactions. In most cases, animals pay for these encounters with their lives. When animals are spared, adjustments in human behavior are needed.

Hungry Bears

Bears became a problem for us when we occupied their territory and intercepted their travel corridors with our own corridors. Our relationship with bears became lethal when they learned that we are an easy source of food. We created that association partly by feeding them in our National Parks for 60 years by making huge, open garbage dumps available to them. That policy was abruptly abandoned in the 1960s when NPS made a commitment to “restoring natural processes.” NPS mistakenly assumed bears would disappear into the forest quietly and without incident. Predictably, the bears took to raiding campsites and vehicles. There were many grisly deaths of hikers and campers before NPS realized they had created a situation requiring active management. Bear proof containers and trash bins were developed and requirements to use them were rigorously enforced.

Bears being fed by visitors at Yellowstone National Park

Dangerous encounters with bears in wild places are still common. Relocating problem bears to distant, uninhabited locations is rarely successful. Many quickly find their way back. Those that stay are likely to engage in the same behavior and the pressure on them to do so is greater because they are in unfamiliar territory. Bears are reluctantly killed only after they hurt people.

Mary Roach visited Aspen, Colorado, where there are many bears and wealthy animal lovers as well as unlimited resources to prevent fatal conflicts between them. Home owners who experience bear break-ins are coached about how to harden their homes against entry. They are also encouraged to reconsider their landscaping preferences to avoid favorite foods of bears, such as plants that produce berries, fruit, and acorns. The poor sods tasked with keeping the citizens of Aspen safe from wild animals were horrified when the city planted crabapple trees downtown. Patrolling restaurants late at night to enforce requirements that they secure their garbage is another of their thankless tasks.

When birds get in the way

Farmers have been at war with birds for as long as humans have engaged in agriculture, some 10,000 years. Crows, grackles, blackbirds, and starlings are often targets of efforts to eliminate them in agricultural areas. Between 1939 and 1945 about 3.8 million crows in Oklahoma were killed by dynamiting their roosts. A study of that effort found no evidence that either the population of crows or crop production was affected by that campaign because nature adjusts: “Destroy a chunk of a population, now there’s more food for the ones who remain. Through a variety of physiological responses—shorter gestation periods, larger broods, delayed implantation—a well-fed individual produces more offspring than one that’s struggling or just getting by.” This balancing act is known to be true of many other species, such as coyotes and rodents.

Dynamiting rookeries has been abandoned, but the National Wildlife Research Center continues to search for effective methods to deter birds. Many methods of scaring birds have been tried and found to be only temporarily frightening. “It is easy to scare birds away, but much tougher to keep them away.” Scarecrows are the traditional method used by farmers. Research suggests that scarecrows may actually attract birds, because birds associate them with food, like the golden arches on the highway is a signal to pull off for a burger.

When the twin towers collapsed on 9/11, there was a real world test of our ability to haze birds. About 2,000 human corpses were scattered among the debris of the towers. Within 3 days, the gulls arrived to scavenge in the debris. Harmless explosions were used to scare the gulls. When the gulls became accustomed to the explosions, those guarding the human remains resorted to shooting and killing the gulls. Twenty-three gulls were shot and their remains were hung in effigy over the debris pile as a warning to their brethren.

Gullls scavenging a garbage dump. Attribution

These experiences with hazing birds should be a lesson to those who plan to dump 1.5 tons of rodenticide on the Farallon Islands to kill mice. There are about 250,000 gulls living on the Farallon Islands and they are expected to eat poisoned mice, but the perpetrators of this deadly project want us to believe they can scare the gulls away from the islands before two poison drops about 21 days apart. 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, how can we believe that hazing will be effective long enough to save the gulls? Must we shoot gulls to save other gulls? Is this the Hobson’s choice “restorationists” ask us to make?

Human attitudes toward animals

Humans are ambivalent about wild animals. We have an abstract sympathy for animals that can quickly dissolve when animals get in our way or we feel threatened by them. Our sympathy is universal, but is often influenced by cultural attitudes. India is a place where we can observe this conflict between our sympathies and our physical need for food and safety.

Hindu deity Krishna and his cow companion. Attribution

Hinduism is the predominate religion in India and respect for animals is a central theme in Hindu life. Many of the gods in the Hindu pantheon are animals. Ganesh, the elephant god, symbolizes wisdom, understanding, and an astute intellect. Hanuman, the monkey god, is a central character in the Hindu epic Ramayana. Cows are sacred in India and roam freely through suburban neighborhoods where poor people share the food they have with revered cows. The line between humans and animals is obscured by the Hindu belief in reincarnation. The cow wandering in the neighborhood could be your departed uncle returned to Earth in the exalted status of a sacred cow. He must have had good karma!

As we should expect, many Indians make every effort to spare the lives of animals, even when they are destructive. Elephants must travel long distances to find the great quantities of vegetation they eat and their corridors are often obstructed by human activities. Elephants often resort to eating and trampling crop fields of poor farmers, who quite rightly are outraged by their loss. Indian officials who are responsible for the lives of the elephants are deeply committed to protecting people and elephants. They try to create refuges for the elephants to minimize their raids on agricultural crops. With a growing population and diminishing wild land, this is a challenging task.

Monkeys are difficult to control partly because they are very intelligent. In a national park with many naïve visitors, monkeys have learned to pilfer valuable objects from tourists, such as glasses and phones, and then barter with the tourists for food that is equally valuable to the monkey.

Attempts to prevent deadly tiger attacks are particularly sad because they are often fatal for both humans and tigers. Tigers are stealthy hunters at night and even in daylight. School children walking to school are attractive prey for tigers as well as women who must walk into the forest alone at night to relieve themselves where there are no available latrines. Animal rangers try to mitigate for these encounters by building latrines and urging children to walk to school in groups.

When a tiger kills, human sympathy is stretched beyond its capacity to tolerate loss. Angry mobs sometimes kill the first tiger they encounter after such incidents. Rangers counsel patience while they hunt for the culprit and confirm its guilt with a DNA test. Rangers are willing to kill a tiger that has been confirmed as a killer.

The need for tolerance

Mary Roach manages to give us a happy ending by visiting a feed lot where beef and dairy operations send their cattle to be raised. The grain elevator where animal feed is stored is swarming with mice, but the fellow who runs the feed lot just shrugs them off: “In the grand scheme of things, the wind probably blows away more than the mice eat. You know, so I’m not sure that’s a huge problem.” He has barn cats to keep mice out of his vehicles where they can chew up wiring. Other than that, he doesn’t see much point in pursuing the mice.

Mary Roach sees hope in this encounter: “To me, he represents a possible future where people may be frustrated by wild animals that get up in your business but they’re living with them. In that possible future, people’s reaction to the damage brought about by wildlife is something akin to acceptance.”

A timely reminder

I publish this article today as a reminder that on Thursday, December 16, 2021, the California Coastal Commission will consider the approval of the project on the Farallon Islands that will aerial dump 1.5 tons of rodenticide on the marine sanctuary to eradicate mice. If you are ready to accept the existence of mice where they have lived in peace with hundreds of thousands of birds and marine mammals for nearly 200 years, please consider writing a public comment or making an oral comment at the hearing. Here’s how to do it.

Send written comments 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.

All quotes are from Fuzz by Mary Roach (W.W. Norton & Company, 2021)

It’s time to comment on the deadly project on the Farallon Islands

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.

Update: The project on the Farallon Islands that will aerial drop 1.5 tons of rodenticide to kill mice that have lived there for over 200 years was approved by the California Coastal Commission on December 16, 2021. Speakers in opposition to the project did an outstanding job. Jane Goodall recorded a message against the project. The vote was 5-3. Doubtful Commissioners asked some excellent questions and did not receive clear answers from US Fish & Wildlife. As the meeting wore on over 7 hours, the project made less and less sense. https://www.sfchronicle.com/climate/article/California-Coastal-Commission-approves-mouse-16709056.php

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.

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 hundreds of thousands 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.