Climate Change vs. Biodiversity: NOT!!

A new study reported changing public and scientific interest in biodiversity compared to climate change.  Using reports in the media and scientific journals in the United Kingdom and the US, as well as funding of scientific studies by the World Bank and the National Science Foundation, the study reports that the interest in climate change has increased and the interest in biodiversity has decreased in the past 25 years.

This analytical approach seems to suggest that these two environmental issues are mutually exclusive, that the interest in one is at the expense of the other.  We find this both unfortunate and unnecessary because we consider these two issues intimately related.  Climate change is increasingly the biggest threat to biodiversityIf plants and animals are unable to adapt to climate change, they are doomed to extinction. 

Therefore, we believe that science should study these topics together.  In fact, the study on which we are reporting acknowledges the relationship between these topics:  “Dual-focus projects are being funded more often, but… ‘this is relatively small and does not mitigate the plateauing expenditure on biodiversity research.’” (1)

Conservation in a changed climate

As long as conservation and “restoration” projects are devoted to replicating historic landscapes, they are likely to be unsuccessful.  The climate, atmosphere, and soil conditions are no longer suited to a landscape that existed hundreds of years ago, particularly in urban environments.  Therefore, if biodiversity is to be preserved by conservation and restoration, such projects must look forward, not backwards. 

We have been watching the Nature Conservancy closely for signs that it is adapting to climate change.  We look to the Nature Conservancy to lead the way because they employ hundreds of scientists.  In contrast, many mainstream environmental organizations employ more lawyers than scientists.

We have reported that the Conservancy’s Chief Scientist, Peter Kareiva, is at least paying lip service to an approach to conservation that takes into consideration the profound changes in the environment caused by the activities of man.  This acknowledgement of the irreparably altered environment is encapsulated by the proposal to name a new geologic era, the Anthropocene.

Unfortunately, the old guard of conservation biology has engaged in a vigorous campaign to silence the Conservancy’s new approach.  This conflict between the old guard and scientists who have proposed a more realistic approach to conservation was recently reported by the New Yorker. (2)  According to that article, Peter Kareiva has made a commitment to the old guard to quit publishing anything regarding the Anthropocene and its implications for conservation practices.

The Nature Conservancy has responded to the article in the New Yorker in its on-line blog.  It doesn’t explicitly address the question of whether or not a commitment has been made to quit advocating for a more realistic approach to conservation.  However, it implies that the Conservancy plans to continue on a course of scientific innovation and experimentation, which it describes as “practical.”  Here is a specific choice made by the Conservancy that typifies this approach:

Monarch butterflies roosting in eucalyptus tree.
Monarch butterflies roosting in eucalyptus tree.

“We know it was worth spending millions of dollars to rid Santa Cruz Island of non-native pigs.  But we are pretty sure it would not be worth spending what could be hundreds of millions of dollars to rid California of non-native Eucalyptus trees (which also happen to harbor wildlife and monarch butterflies.)” (3)

Although the Nature Conservancy’s Chief Scientist may have agreed to “shut up,” we see signs of the Conservancy’s new approach in its latest magazine.  In a brief article entitled “Forests of the Future,” the magazine reports that they are no longer planting the species of trees that existed in the past in one of their properties in Minnesota, because they don’t believe that species is adapted to current or predicted future conditions.  Instead they are actively engaged in reforestation of the land with new species:

Over the past two springs, the team planted 88,000 tree seedlings across 2,000 acres in the northeastern corner of the state.  The seedlings consisted of species that should survive better in a warmer and drier climate—trees, such as red oak, found in higher numbers just south of the area. For a team accustomed to restoring forests to match historical landscapes, helping the North Woods [of Minnesota] adapt to a predicted future climate is a new but necessary idea.  [The Conservancy’s science director in Minnesota] says, ‘All of our modeling is saying the same thing,’ she adds, ‘We needed someone to actually go out and start trying some of this stuff.’” (4)

Looking forward not back

We are very encouraged by the Conservancy’s new approach and we hope that other land managers will be inspired by it.  We are also reminded of a recent visit to a nature reserve near San Luis Obispo managed by the local chapter of the Audubon Society.  We reported about this reserve in a recent article because the land managers had planned to destroy all eucalyptus trees on that property but were forced to scale back their plans in response to a noisy negative reaction from the public.

Dying oak tree, Sweet Springs Nature Reserve
Dying oak tree, Sweet Springs Nature Reserve

On our recent visit, we learned that this was a wise choice because many of the oak trees that were planted on this reserve by those who wish to “restore” it are quite dead despite the fact that the reserve has an extensive irrigation system.  These land managers looked back and the result of that retrospective thinking is a landscape of dead native trees.

Irrigated native plant garden, Sweet Springs Nature Reserve
Irrigated native plant garden, Sweet Springs Nature Reserve

Climate change requires land managers to wake up to the realities of what will grow where.  Land managers in the San Francisco Bay Area appear to be blind to that reality.  They repeatedly plant species where they grew hundreds of years ago and we are forced to watch the plants die repeatedly. 



(1)    “Climate change beats biodiversity as a press, scientific, and funding priority,” Science Daily, June 11, 2014

(2)    D.T. Max, “Green is Good,” New Yorker, May 12, 2014

(3) Mark Tercek and Peter Kareiva, “Green is Good:  Science-Based Conservation in the 21st Century,” May 5, 2014

(4)    “Forests of the Future,” Nature Conservancy, June/July 2014

Peter Kareiva redefines conservation biology

Who is Peter Kareiva and why do we care about his definition of conservation biology?  Kareiva has been the Chief Scientist at the Nature Conservancy since 2002.  That’s a BIG job, given that the Conservancy employs about 600 scientists.  The huge number of scientists at the Conservancy is one of the reasons why it is unique amongst environmental organizations.  Most environmental organizations employ more lawyers than scientists.

The Nature Conservancy is the “leading conservation organization working around the world to protect ecologically important lands and waters for nature and people,” according to its website.  These measures of its scale are an indication that they aren’t exaggerating:

  • There are over one million members of the Nature Conservancy (of which our household is one).
  • They have protected more than 119 million acres of land, thousands of miles of rivers and created over 100 marine reserves worldwide.
  • They have projects in all 50 states of the US and 35 countries around the world.

The Conservancy restores as well as conserves

Trees destroyed in Chicago for prairie "restoration"
Trees destroyed in Chicago for prairie “restoration”

Another reason why we are interested in the opinions of Peter Kareiva is that the Nature Conservancy engages in some of the most aggressive restorations of which we are aware.  One of their famous projects is the return of tall grass prairie around Chicago, Illinois, which required the destruction of untold thousands of trees, many of which were native.  These projects began decades ago and have generated a great deal of conflict amongst those who value the trees and object to the methods used to kill them, including herbicides and prescribed burns.

Another famous Conservancy restoration is on the Channel Islands, off the coast of California.  Thousands of non-native animals were removed or killed.  Native mice were rounded up in order to carpet-bomb the islands with rodenticides to kill rats.  Feral pigs had been the preferred food of the Golden Eagle, which then turned to the rare Channel Island fox as a substitute when the feral pigs were exterminated.  So, the Golden Eagles were captured and shipped elsewhere.  Thanks to a captive breeding program the Channel Island fox was spared extinction.  Feral honeybees are also being exterminated because they are not native.  This is but a brief description of the extreme measures taken on the Channel Island to rid them of all traces of human habitation.

Channel Island Fox
Channel Island Fox

Peter Kareiva defines conservation goals

We were introduced to Peter Kareiva shortly after he joined the Conservancy, after a long career in academia.  In 2002, he was quoted in an article in the New York Times entitled, “As Alien Invaders Proliferate, Conservationists Change their Focus.”  As the title implies, this article reported on the emerging scientific consensus regarding ecological restorations:  “…a growing chorus of biologists is proposing a new approach to the fast-blending biosphere.  They also say change should be accepted as largely inevitable and choices for managing nature should be based on what is desirable and undesirable, not what is native and foreign.”  Peter Kareiva was one of the scientists supporting this new viewpoint:  “’Conservation biologists are too romantic,’ Dr. Kareiva said, ‘They think what’s good is what’s natural.  Let’s be serious.  A better vision is something that functions and has habitat quality and aesthetic quality.’” 

We have been following Kareiva’s career since that interview and he has become increasingly vocal in his opposition to out-dated notions of creating “pristine” historical landscapes.  He is now one of the proponents of naming the current geological era the Anthropocene in recognition of the reality of man’s pervasive impact on the environment.

In 2012, Kareiva and a co-author published a manifesto redefining conservation biology, which was defined by Michael Soulé in 1985. (1) As defined by Soulé, it was solely a biological science focused on biodiversity, and human influence was perceived as detrimental to its goals.  It was considered a “crisis science” which advocated for action in the absence of data because of the urgency of reversing environmental damage.

The world has changed significantly since 1985.  Human population has increased from 4.8 billion to more than 7 billion in 2011.  Energy consumption has also increased significantly as developing countries approach the standard of living of developed countries.   There is a growing understanding that human activities have altered even remote corners of the earth.  The preponderance of novel ecosystems has rendered irrelevant earlier notions of the importance of co-evolution in static ecosystems.  There is also waning political will to impose standards for conservation that are antithetical to the interests of humans.

Kareiva therefore proposes a new approach to conservation, which he calls conservation science.  It must be a multidisciplinary science which incorporates social science because it must accommodate both biodiversity and the needs of humans.  These are the core principles of conservation science:

  • ”First, ‘pristine nature’ untouched by human influences, does not exist.”
  • “Secondly, the fate of nature and that of people are deeply intertwined.  Human health and well-being depend on clean air, clean water, and an adequate supply of natural resources for food and shelter.”
  • “Third, nature can be surprisingly resilient.”
  • “Fourth…sustainable conservation can be achieved by empowering local people to make decisions for themselves.”

These are the values of an ecological philosophy to guide conservation actions:

  • “First, conservation must occur within human-altered landscapes.”
  • “Second, conservation will be a durable success only if people support conservation goals.”
  • ”Third, conservationists must work with corporations” because they “drive much of what happens to our lands and waters.”
  • “Fourth, only by seeking to jointly maximize conservation and economic objectives is conservation likely to succeed.”
  • “Finally, conservation must not infringe on human rights and must embrace the principles of fairness and gender equality.”

Kareiva concludes:

“Our vision of conservation science differs from earlier framings of conservation biology in large part because we believe that nature can prosper so long as people see conservation as something that sustains and enriches their own lives.  In summary, we are advocating conservation for people rather than from people.”

Bringing this message home

We hope that Kareiva’s viewpoint is driving the Nature Conservancy’s projects, but we don’t have enough detailed knowledge of those projects to know if this is the case.  However, we do know that the many “restoration” projects on our public lands in the San Francisco Bay Area do not conform to Kareiva’s standards because:

  • Local projects do not reflect the wishes of the community.  In most cases, the community was not even aware of the projects until they were completed.  When the public has had an opportunity to object to the projects, their objections are largely ignored.
  • Local projects use pesticides and many conduct prescribed burns.  These methods used to eradicate non-native plant species are harmful to the environment and the people and animals that live in it.
  • Local projects often exclude people by building fences around projects, closing trails, and restricting all recreational access to the trails.  Our local projects treat the public like intruders.

If the world’s largest conservation organization can redefine its goals to accommodate the needs of humans, what possible excuse do managers of our public lands have to ignore the public’s wishes?  The Nature Conservancy is responsible for lands acquired with the voluntary charitable contributions of its donors.  In contrast, the public owns our public lands and pays for the management of those public lands with our tax dollars.  Shouldn’t the managers of our public lands be more accountable to the public (who pay taxes whether they want to or not) than the Nature Conservancy is to its donors (who can choose not to donate)?


(1)    Peter Kareiva and Michelle Marvier, “What is Conservation Science?” BioScience, November 2012, Vol. 62, No. 11

The unintended consequences of micromanaging nature

We must tell our readers about the collateral damage of misguided attempts to manage nature more often than we would like.  We prefer positive stories, but in the hope of a better future we must also inform the public of the unintended consequences of the many projects that are killing one species of plant or animal based on the mistaken assumption that another plant or animal will benefit. 

Trumpeter swan by James Audubon
Trumpeter swan by James Audubon

In this case, a project sponsored by the Nature Conservancy decimated the population of rare Arctic grayling fish in Centennial Valley, Montana, by damming the streams to create ponds for the benefit of the equally rare trumpeter swan.  The grayling had spawned in those streams and the population plummeted when the streams were dammed. 

The Nature Conservancy scientist who was interviewed by National Public Radio for this story said, “There are lots of examples where we try something that sounds like a good idea [and it] turns out not to be that good of an idea.  Then [we] remedy it and—hopefully—never try it again.”    

Unfortunately, they ARE trying it again.  Now the scientists are trying to compensate for the damage to the grayling population by killing cutthroat trout that is considered a predator to the grayling.  The cutthroat is not native, so that also makes it a candidate for eradication.  It’s as though we are on a killing treadmill.  One mistake seems to lead to another. 

Stop and think before you shoot!

Cockatoo.  Creative Commons
Cockatoo. Creative Commons

A bird lover in Hawaii takes a more thoughtful approach to the suggestion that introduced cockatoos and African parrots should be shot, based on the assumption that they are competing with the dwindling population of native birds.  He points out that the native birds nest in the ground, while the cockatoos and parrots nest in cavities in the trees.  Most of the native birds are nectar eaters, while the cockatoos and parrots eat seeds and nuts.  So, he wonders if the introduced birds are really a threat to the native birds.

The exotic birds are either escaped pets or the descendents of them.  The author of the article urges pet owners to take care of their pets and make a permanent commitment to their care.  Releasing them into the forest is making them a target for people who think killing them would benefit other birds. 

The author is not opposed to killing non-native animals when absolutely necessary, but he is at least willing to carefully consider if it is necessary, in his opinion.   He is comfortable with the killing of rats, pigs, and feral cats, for example.

Million Trees takes this question a step further.  We don’t think humans should micromanage nature.  We don’t have enough information to presume to know better than nature what is best.  We also have our own anthropomorphic criteria for which species is more important than another.  Our judgment is self-serving and is not a substitute for the even-hand of nature.   Nature follows the simple rule of “survival of the fittest.”  Nature is as likely to save the lowly spider as it is to save the beautiful trumpeter swan.

A parable to illustrate the point

This parable, retold in Fanaticism of the Apocalypse (1) illustrates the futility of man’s attempt to control nature:

“Noah, as he is loading the animals onto the Ark, is alarmed by the large number of candidates.  Mammals, birds, marsupials, penguins, primates, and lizards have already gone on board.  The ass, the ox, the giraffe, the elk, the stag, the lion, and the cat urge the patriarch to raise the gangplank and close the hatches.  The boat is chock-full, the cedar hull is about to crack open, the Deluge is threatening.  Outside, a crowd of harmful or misshapen pests—cockroaches, toads, slugs, spiders—asks to be taken on.  The toad speaks on behalf of his unsightly comrades:  he pleads their cause with eloquence, pointing out to the Patriarch that they perform a useful function in nature.  In God’s design, nothing is ugly or repugnant:  everything is ingenious, even invertebrates, mollusks are necessary.  No one has the right to destroy these creatures of the Lord.  But Noah turns on his heel and decides to raise the anchor.  Then a cloud of insects and pests assails him:  fleas climb on his legs, crabs crawl in his pubic hair, lice swarm on his head, leeches, stinkbugs, and mosquitoes stick to his skin without him noticing them.  Snakes slip into his flowing hair, spiders take up residence in his beard.  That is how the whole bestiary was spared.”

We fiddle with nature at our own peril. 


(1)    Pascal Bruckner, The Fanaticism of the Apocalypse, Polity, May 2013

Cultural Lag: Public policy lags behind science regarding “invasion biology”

This is a good-news-bad-news story.  The good news is that the most successful environmental organization devoted to the preservation and conservation of wildlands, The Nature Conservancy, has announced its intention to reorder its priorities in what we hope will be a less destructive direction.  The Conservancy is a science-based environmental organization that is unique in that regard.  It employs over 600 scientists to guide and inform its projects, in contrast to many other organizations that employ more lawyers than scientists.  The scientific orientation of the Conservancy undoubtedly puts it in a position to reflect and respond to the increasingly loud voices of other scientists who are expressing concern about the costs and environmental damage that are the unintended consequences of the “restorations” which have evolved out of invasion biology.

The bad news is that public policy regarding native plant “restorations” lags far behind the developing scientific consensus regarding invasion biology, namely that original theories require revision.  This is the consequence of the cultural lag that is inevitable when science moves forward, but communication of its findings to the general public lags behind. 

The Nature Conservancy redefines its goals

In the past few months, the Chief Scientist of the Nature Conservancy, Peter Kareiva, has written several articles in the Conservancy’s publications expressing his views about the future of conservation.  In “Beyond Man vs Nature,”(1) Kareiva is quoted as saying that species preservation should not be the top priority of the Conservancy.  He admits he is “not a biodiversity guy.”  Rather, he says, “The ultimate goal [should] be better management of nature for human beings.”  He does not agree with those who claim that the earth is fragile and man must be excluded from nature in order to protect it.  He considers nature resilient.  He calls the concept of “biodiversity hot spots” sham science and he rejects the notion that conservation and development are mutually exclusive.  We wants conservation efforts to focus on the things that people need from nature such as clean water and clean air.  If and when people experience the benefits of conservation, they will support and participate in those efforts.  The Conservancy can’t save the world alone.  The active participation of the human population is required to achieve the Conservancy’s conservation goals. 

Golden Gate Park San Francisco. Most plants and trees in GG Park are not native. Creative Commons Attribution - Share Alike

In “Conservation should be a walk in the park, not just in the woods,”(2) Kareiva says that the Conservancy should participate in more urban conservation projects because that’s where most people live and even more will live in the future.  He wants conservation to be more visible to people and he wants people to benefit directly from the projects.

In his most recent publication, “Invasive Species:  Guilty until proven innocent?” Kareiva acknowledges the debate about invasive species.  On the one hand, a few invasive species have done a great deal of harm, particularly on islands.  On the other hand, many invasive species aren’t doing any harm and some are benefitting native species, even endangered species in some cases (e.g., Southwestern Willow Flycatcher in Tamarisk).  He concludes, “Science-based conservation cannot be about knee-jerk platitudes and simple views of good and evil…the fact is we cannot control all invasive species, and in many cases, yesterday’s invaders have become plants and animals that are beloved by local people.” 

There is nothing scientifically new to us in what Kareiva has said recently.  What’s new is that he speaks as a representative of one of the most important environmental organizations in the world.  Therefore, he makes a connection between scientific theory and action.  That is new….very, very, new and very encouraging.

Public policy always lags behind science

Public policy is inherently conservative.  It usually reflects consensus and consensus occurs late in every scientific debate.  Once that consensus is finally reached, changing it is a slow process.  And so, we are not surprised by the most recent example of a local community continuing the crusade to eradicate non-native trees.  Two ordinances were recently passed in the Los Altos Hills on the San Francisco peninsula, to do just that. 

  • Citizens building or expanding buildings on their properties will be required by ordinance 10-2.802 to cut down all eucalypts within 150 feet of any roadway or structure.
  • “Town guidelines concerning restoration action” (5-8.08) “deems certain trees undesirable,” including Monterey pine and cypress, as well as eucalyptus.

We are heartened by the publication which announces these new policies.  The author objects to being dictated to regarding her tree preferences.   She also responds to the usual myths regarding the negative qualities of eucalyptus.  In response to the usual justification for its eradication, that it is not native, the author says, “Who cares?”  Indeed, who cares?  We certainly don’t care and we speculate that the vast majority of people in Los Altos Hills don’t care either.  When we speak up on behalf of our trees, we speed the process of changing public policy to reflect the considerable scientific evidence that non-native trees are not harming anything or anyone.   Indeed, their eradication is causing far more harm to the environment by releasing tons of sequestered carbon and requiring greater herbicide use.    

(1) Nature Conservancy, Spring 2011

(2) Nature Conservancy, Issue 2, 2011

Exterminating Animals: Wasted lives and money

While we object to the needless destruction of non-native plants and trees, we are even more concerned about the destruction of non-native animals.  Using the same justification, namely that non-native animals out-compete native species of animals, native plant advocates and their allies are equally committed to the eradication of non-native animals.  The list of targeted animals is long: e.g., non-native frogs, turtles, fish, bees, foxes, opossums, squirrels, deer, pigs,etc.  When populations of native animals increase in urban areas, they are called “subsidized predators” and added to the death list: e.g., raccoons, skunks, etc.  A native animal can land on the death list if its range expands, such that it becomes a competitor for a preferred, rare native animal.

First we will indulge in a brief digression on behalf of the non-native European honeybee, one of the few species of bee in the United States that produces honey.  If that’s insufficient reason to defend its existence, let us consider that the European honeybee is responsible for pollinating about one-third of all agricultural crops and orchards in our country(1).  Even without eradication efforts, the honeybee is in trouble.  In the past several years, about one-third of all hives have failed each year from multiple factors summarized as “Colony Collapse Disorder.”  Despite the obvious value of this non-native creature, it is being eradicated by the Nature Conservancy on its “restorations” in the United States because it is non-native and it is considered a competitor to native bees, which are not capable of pollinating many agricultural crops or making honey(2).  This seems to us a classic case of nativism shooting us in the collective foot.

Now we will turn to two efforts to exterminate animals that were both appallingly destructive, but more importantly, ineffective and clearly a waste of both lives and taxpayers’ money.  The first example is historical, illustrating that man’s efforts to manipulate nature to serve his purposes are not new and undoubtedly can be traced as far back as the historical record can take us.

California Quail, Wikimedia Commons

In this case, we will look at the efforts of the California Division of Fish and Game to increase the population of quail(3).  Quail are native to California, but their population exploded with the arrival of Europeans whose agricultural and grazing practices increased the food supply of the quail.  The population of quail in California reached its peak during the period 1860 to 1895 and thereafter began to decline as non-native annual grasses began to dominate the non-native herbaceous and leguminous plants that preceded them.  Since man’s view of nature is rather narrow in time, limited by his brief lifetime compared to the more slowly moving forces of nature, the California Division of Fish and Game perceived the decline in the quail population as a problem requiring remediation.  One of their proactive efforts was to exterminate all animals believed to be predators of the quail.  This “predator control” effort was summarized for one six-month period as follows:

“…between January 1 and July 1, 1931, [deputies of the Division of Fish and Game] have destroyed…:  38 coyotes, 33 bobcats, 684 house cats, 35 foxes, 43 coons, 8 weasels, 2 opossums, 1 badger, 5 wild and unclaimed dogs…365 sharp-shinned and cooper hawks, 3972 blue jays, 293 magpies, 81 crows, 49 butcher birds, 2 great horned owls, and 47 snakes.”(4)

The Division of Fish and Game hired an army of 45 full-time men in 1948 to continue this war on the perceived enemies of quail.  This extermination effort was not abandoned until 1957, when the Division of Fish and Game concluded that the quail population was not benefitting from this animal holocaust and that reduced food sources and cover, resulting from changes in land uses and consequent vegetation types was the reason for the declining quail population.  In other words, hundreds of thousands of animals lost their lives over a period of over 25 years for no reason whatsoever.

So, did we learn anything from that experience?  Clearly not.  Today there are nearly as many programs to eradicate non-native animals as there are non-native species.  We choose the brown-headed cowbird as an example of modern eradication efforts because it is occurring in California (5).

Although the brown-headed cowbird is native, it is perhaps one of our most reviled birds because it is a nest parasite, which means that it lays its eggs in the nests of other birds.  Their egg is usually larger than the eggs of the “host” bird and it hatches earlier than its nest-mates.  The result of these advantages is that the off-spring of the nest owner usually does not survive, but the cowbird chick survives to repeat this trick.  Because the range of the cowbird has been expanding, it has been blamed for the declining population of songbirds.

But does the cowbird deserve to be blamed for the decline in the songbird population?  Professor Stephen Rothstein (Department of Ecology and Evolution, UC Santa Barbara) says, “NO.”  He tells us that the range of the cowbird is not larger than its historic range.  At the time of the megafauna (e.g., wooly mammoths), about 15,000 to 20,000 years ago, cowbirds probably occupied their current range.  When the megafauna disappeared, the range of the cowbird shrank.  As in the case of the quail, we look to man for the explanation for why its range has expanded again:  the introduction of large grazing animals by Europeans has provided the cowbird with a substitute for its prehistoric food source.

Professor Rothstein tells us of several efforts to exterminate cowbirds on behalf of declining populations of songbirds and concludes that although songbird populations may have recovered in some cases, the extermination of cowbirds is not the likely explanation for their recovery.

Kirtland’s Warbler, female, Wikimedia Commons

The recovery of the Kirtland’s Warbler in Michigan is a case in point.  The warbler’s nesting habitat was well known to require periodic fire.  Yet, the scientific managers of this recovery project preferred to kill cowbirds rather than to risk human life and property by not suppressing fire.  Nearly 125,000 cowbirds were destroyed in a portion of a small peninsula in Michigan during the period 1972 to 2002.  Although nest parasitism declined significantly, the population of Kirtland’s warbler did not increase until over 20 years later after a large accidental forest fire.  In other words, the cowbird is a scapegoat for the choices made by man, in this case the suppression of fire.

Like the predator control project on behalf of the quail, cowbird extermination projects create jobs.  The Kirtland’s Warbler project continues to cost about $100,000 per year, although there is no evidence that the warbler is benefiting from it.  Rothstein speculates:   ”The money spent on cowbird control every year may total more than one million dollars.”   This creates a profit motive which Rothstein says results in a “control lobby” that advocates for continuing the program whether or not it is effective.  He believes that this money would be put to better use by addressing the underlying problems, such as habitat loss to development or reduced water levels that change vegetation types, as in the case of the declining population of the Southwestern Willow Flycatcher.

These are familiar themes to the readers of Million Trees:

  • That native plant advocates and their allies frequently confuse cause and effect, e.g., cowbirds are not responsible for declining songbird populations.
  • That man finds it convenient to scapegoat plants and animals for changes in the environment that are caused by man.
  • That people who make their living in these misguided “restoration” efforts have a vested interest in their continuation whether or not they are effective
  • That the waste of money and scarce resources prevents us from addressing the real issues
  • That choosing to replicate nature at some specific point in historical time is illogical because nature is constantly changing, not always in response to the actions of man

Postscript:  Here is a link to a radio story about another episode in the attempt to save the Kirtland’s warbler.  After killing 125,000 cowbirds (according to the ABA article), US Forest Service changed its mind about why the population of Kirtland’s  warblers was dwindling.  They decided that the problem was that the warbler required young trees of a specific species, which is germinated by fire.  So, they set a prescribed burn that caused a wildfire on a windy day, burning over 20,000 acres, destroying 41 homes, and killing a young man who worked for the Forest Service.  The population of Kirtland’s warblers rebounded.  Now the Forest Service says they must continue to kill cowbirds and set prescribed burns every year forever if the Kirtland’s warbler is to survive.  This radio program poses the question:  does this make sense?    


(3) A. Starker Leopold, California Quail, University of California Press, 1977. (N.B. A. Starker Leopold is Aldo Leopold’s son.)

(4) Ibid.

(5) Rothstein, Stephen, “Brown-headed Cowbird, Villain or Scapegoat?,” Birding [journal of American Birding Association], August 2004, 374-384.