Because the beaver isn't just an animal; it's an ecosystem!

Tag: Beaver population


Well yesterday was fun, with little messages of encouragement for our 10th year  from folks around the globe. Now it’s time to get back to work. You know what they say, before anniversaries “Chop  wood, carry water“, and after anniversaries”Chop wood carry water“. Or something like that.

Here are two articles that deserve our attention. I’ll start with the grating one first. Why is it every article written about Peter Busher annoys me more than it interests me? Over the years I have come to think he basically knows his beavers, but he honestly doesn’t seem to like them very much.

The Secret Sex Lives of Beavers

The population boom can raise alarms in communities. Beavers are often viewed as a nuisance, causing millions of dollars in damage each year by chewing fences, trees, and decks. They build dams, which leads to flooding of homes, crops, and railroads.

But some behaviors can be beneficial, says Peter Busher, a College of General Studies professor of natural sciences and mathematics and chair of the division. Beaver dam building expands wetlands, whose functions include filtering toxins from water, supporting biodiversity, and mitigating floods.

Peter Busher poses with beaver captured for analysis

Busher has been studying beavers for four decades and was the first person to track the animals by tagging them with radio transmitters. He does his research in the Quabbin Reservation in Central Massachusetts, where 150 to 300 beavers con­stitute the nation’s longest-studied population, says Busher. Hoping to learn how humans can better coexist with beaver populations, he examines mating habits, birthrates, group structure, and how the animals migrate from one area to another. His findings could inform deci­sions about how communities respond to beaver activity and manage the animal’s population, both in Massachusetts and across the country.

Although beavers are among only 3 percent of mammals that are socially monogamous, raising their young exclusively with one partner, researchers do not know much about their pairing behavior. Do the parents also mate with other beavers and raise a mixed brood, or are they sexually exclusive? Busher wants to find out. He suspects that genetically monogamous beaver populations—those that tend to mate with one partner—increase more slowly and may stay in an area longer. If one of these populations were removed because of nuisance activity, he says, the area would likely be free of beavers for a while. But if the population were more promiscuous, new beavers could move into the area at any time; communities would then need to develop a long-term animal removal plan.

Promiscuous beavers? Honestly? Is that honestly what you think? Who thinks like that? Have you looked at every OTHER variable in their habitat that might differ between various beavers to rule out that food availability, or population, or stream gradient and prove that these it doesn’t influence which beaver are promiscuous and which aren’t? I’m sure, as a scientist, you would do ALL THAT before LEAPING to the assumption that DNA is responsible. I mean this is almost like race research.

How much trouble would you be in if you were posing that certain ethnicitys were more promiscuous?

The best research I have read on the topic described beavers as “opportunistic monogomists” – meaning if the right conditions happened to arise they would take advantage of them and mate outside the pair bond, and if they never arose it would be mostly okay with it and get on with the business of taking care of the family. I remember being amused when Rickipedia commented that this was pretty much the same for most male humans.

But Dr. Busher is trying to prove that it’s a beavers genes that make him roam. So that those prolific beavers we can kill more, and the faithful homebodies we can work with.

Are you sure you teach in Massachusetts? Because this theory is starting to sound positively republican to me!


The article that really interested me today comes from the irreplaceable George Monbiot and discusses the use of better language about ecology to capture public interest. Rusty of Napa sent it my way and I’m glad he did.

Forget ‘the environment’: we need new words to convey life’s wonders

If Moses had promised the Israelites a land flowing with mammary secretions and insect vomit, would they have followed him into Canaan? Though this means milk and honey, I doubt it would have inspired them.

So why do we use such language to describe the natural wonders of the world? There are examples everywhere, but I will illustrate the problem with a few from the UK. On land, places in which nature is protected are called “sites of special scientific interest”. At sea, they are labelled “no-take zones” or “reference areas”. Had you set out to estrange people from the living world, you could scarcely have done better.

The catastrophic failure by ecologists to listen to what cognitive linguists and social psychologists have been telling them has led to the worst framing of all: “natural capital”. This term informs us that nature is subordinate to the human economy, and loses its value when it cannot be measured by money. It leads almost inexorably to the claim made by the government agency Natural England: “The critical role of a properly functioning natural environment is delivering economic prosperity.”

I’m fully on board with the need to use language that enlivens and engages us rather than regulates our attention. But sometimes we are talking to politicians or biologists and need to convince them, and we think that kind of language carries more sway? Maybe it doesn’t. Maybe the only thing that matters to decision makers is what we celebrated yesterday: public pressure and votes. So engaging the public is more important than sounding objective.

This is my FAVORITE part.

On Sunday evening, I went to see the beavers that have begun to repopulate the river Otter in Devon. I joined the people quietly processing up the bank to their lodge. The friend I walked with commented: “It’s like a pilgrimage, isn’t it?” When we arrived at the beaver lodge, we found a crowd standing in total silence under the trees. When first a kingfisher appeared, then a beaver, you could read the enchantment and delight in every face.

Our awe of nature, and the silence we must observe when we watch wild animals, hints, I believe, at the origins of religion.

Something about that sentence feels very, very true for this woman who spent so many years in the company of beavers. (Not that we were silent the whole time.) Our beavers had train whistles and garbage trucks to get used to, and could handle a little talking. But there was definitely awed silence at times. Like when kits emerged or when an uncommon behavior was scene.

And it sure felt like the very best parts of church to me.

if we called protected areas “places of natural wonder”, we would not only speak to people’s love of nature, but also establish an aspiration that conveys what they ought to be. Let’s stop using the word environment, and use terms such as “living planet” and “natural world” instead, as they allow us to form a picture of what we are describing. Let’s abandon the term climate change and start saying “climate breakdown”. Instead of extinction, let’s adopt the word promoted by the lawyer Polly Higgins: ecocide.

We are blessed with a wealth of nature and a wealth of language. Let us bring them together and use one to defend the other.

Thank you, George for another beautiful column. I’m envious of the people who got to walk alongside you on the way to see those special Devon beavers. We very rarely feel reverence for what we consume or eliminate as inconvenient. But I have seen it time again on children’s faces watching our beavers.

Maybe its reverence, more than science, that protects nature.


Way back in June you might remember that I wrote about a study released in the Journal of Human Wildlife Interaction called Toward an understanding of beaver management as human and beaver densities increase.  I had a lot to say at the time about what I thought was a slanted study that worked hard to present the very hopeless argument that would add pressure to overturn the voters decision in Massachusetts.

This study revisits the Massachusetts beaver issue and the least-liked voter decision apparently in the history of the world. A 1996 referendum that indicated folks wanted it to be harder to kill beavers cruelly. This is vociferously blamed for ruining every sense of balance the state had previously developed. Even beaver defenders thought the the referendum had ‘tricked’ the voters (although how straight forward are most ballot issues, I ask you?) Once it was passed, alarming reports filled the air like spring pollen. Authorities said the population subsequently exploded because even though you could still use lethal techniques and even though you could use the old methods as long as one of 9 tiny conditions were met, it still took five minutes more time to kill them than it used to and that created anarchy. (Folks in the bay state are very busy and obviously no one has 5 more minutes to spare killing beavers.)

CaptureHence the article, which is based on public attitudes towards beavers and a questionnairre that got mailed to folks who complained about beavers (and for appearances sake, some folks who didn’t) in 2002. Surprisingly, the folks who DIDN”T COMPLAIN didn’t return the survey as much as the people who were mad. (Gosh!) And the two groups said admittedly different things in general, but the researchers knew just how to handle this conundrum to get the results they wanted.

Well, at the time I had so much to say about the article that I wrote the editor who invited me to write a response. Which I faithfully did and which I was just mailed the proof of yesterday. Meaning response will appear in the Fall issue of Human Wildlife Interactions! My article will be followed by a rebuttal in much the same way as a pinata might be dangled to be whacked by a group of small children, but regardless of my inevitable thwacking, the will be an article about flow devices and how they worked in Martinez published for all the world to see. Flow devices will appear in a Peer Reviewed Journal which I believe will be a first.

I’m very, very happy about this. Oh and since I’m turning 4 feet old today, I thought we all deserve some of this. It’s the best beaver birthday cake EVER!beaver cake


Once upon a time, not too long ago but very far away, there was a prestigiously  educated state on the east coast that was so smart it even put beavers on the class rings of its  university. Because the collective IQ of the state was fairly lofty and the populace fairly liberal,  it decided it didn’t want to use icky leg-hold traps anymore. So  around the time that Clinton was president and the Macarena was popular they passed a law to this effect.

It didn’t take very long before the panic started. “No traps!” they exclaimed in horror. “We will be overrun by wildlife. We will be surrounded by coyotes and drowned by beavers.” But the will of the voters had spoken and the legislators had to do what they said. The state with beaver class rings passed a law saying it wasn’t going to use leg-hold traps or conibears to kill  anymore.

(Unless one of 9 conditions were met and everyone knows that they can almost always be construed to be met but that’s a post for another day.)

The fact is that smart watershed-interested folk around the bay state started to get panicked at this news. The beaver population was exploding. There were going to be too many beavers. Even folks who thought the occasional beavers in moderation were good for the planet, started to get panicked about the massive numbers that were predicted.

Flash forward 20 years, when that exploding beaver population all had kits and exploded some more. An educated man writes me to say that the beaver population has returned to the numbers it had before the fur trade.  He cites the number of beaver dams in a particular area and assumes a surprising number of beavers per dam which means that by his estimate the population is enormous.

Which is why I reposted this lovely illustration from the 1868 writings of Lewis Morgan “The American beaver his life and works” The illustration shows a series of beaver dams in a gorge. 7 to be precise. That’s 7 dams tended by a single colony of beavers. Which means you can’t infer populations directly from the number of dams built. Beyond this research has reported again and again that any colony rarely gets any bigger than 9 and the numbers are usually less. (Our largest colony in 6 years of observation, with parents, yearlings and kits was 8 at one time.)

This means that if you multiply the number of dams counted by any surprising number you will be grossly overestimating the population of beavers. And alarming the populace with your inflated statistics. And killing more than you need to do.

But, you may ask, if people have been watching these beavers all this time and it SEEMS like more isn’t that proof?

In answer to this question I will direct you to something I wrote on this website what seems like a million years ago now but was actually only June 2008.

The kindest interpretation of this is that people see things in a new way when they are alarmed. There are several less charitable explanations. An example: At my old office I had birdfeeders and a number of feathered visitors. Goldfinches, white and red breasted nuthatches, and downy woodpeckers to name a few. My downstairs neighbor complained about seed husks so we would sweep his porch every week to keep it tidy. During one such sweeping event, the crabby old accountant watched with folded arms and said, “What about all the green stuff. Get that too.”

The “green stuff” in question was pollen from the hundreds of pines in the area and had been on his porch every spring for as long as he had been there, but of course he had never seen it before because he had never looked with this particular set of eyes.

And those, as it happens, are the very same eyes that this state looks at beaver with.


Here endeth the lesson.

______________________________________________________________

Nice photos from Cheryl last night, who briefly saw one kit and three adults. Here’s mom inspecting the credentials of her photographer.

Mom beaver: photo Cheryl Reynolds

And what I think is her best photo of a green heron yet.

Green Heron: Cheryl Reynolds

You’ve probably seen the statistic tossed about that our current beaver population is about a tenth of what it used to be. That’s always seemed right to me, but today I really looked a little closer at the numbers. This article, (which dissapointingly isn’t so much an article as it is the back-of-a-cereal-box collection of facts, some of them  accurate), describes a pre-contact population of American beaver at 60,000,000 animals. I was curious how that would actually play out regionally. Leaving out Hawaii which never had beaver, and Alaska which I don’t think was included in this guestimate, that leaves 125000 beavers per state. Not really a helpful statistic when you think about the differing sizes and amounts of water per state.

But what if you look at water miles for the entire contiguous US, Wikipedia tells me we have 160,820.25 square miles of water. Now, this makes a little more sense. 60,000,000 beaver  means about 373 beavers per every 27,878,400 feet of water. That works out to be about 46 colonies for every square mile of water. Or if you are looking at the 35,000,000 miles of river in the United States, that’s about 17 beaver per every mile of stream.

17 per mile! That means that the beaver population of Martinez between Safeway and the train station would more than triple. For California’s 7736 miles of stream that works out to be about 131,512 beavers historically. That’s still not exactly right either because some of them were in lakes and larger bodies of water, but you get the idea. That’s A LOT of beaver.

So the next time you read an article saying that the beaver population has rebounded, think about the 90 percent of those numbers that are still missing. I’m not even sure that the existing population of beavers is larger than or equal to the number of beavers killed every year. Does Fish & Game keep those statistics?

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