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

The Martinez Beavers

Category: Beaver Behavior

When I was a teenager my father was the oversight supervisor for the first major windmill built in Northern California. It was a towering structure with a single blade longer than a football field. It stood atop a barren hill in Cordelia where the wind was sometimes so strong it could hold you upright if you leaned out into it. Standing under it was like being below a giant scythe at harvest that swept by again and again just missing you every time. Years after it was built my father loved to bring guests to its strange wonder, proud of his role in its launch. I remember one of the things I was most struck by at that time was learning that PGE had to hire biologists to identify any birds that were killed by that giant blade and report them. I remember thinking that counting dead birds was a very strange way to make a living.

The giant windmill eventually got a cracked shaft and is no longer standing today. Now there are many windmills all over the state and producing various amounts of power – and all of them have to count the birds they kill. I thought of this because yesterday we learned that the department of the interior just ‘opted out’ of the restrictions imposed by the Migratory Bird Act which has made it illegal to kill birds without permission since 1918.

Interior cancels decades-old protections for migratory birds

Think about that a moment. Since the end of WWI we have agreed with many other countries that killing birds was a big deal. MBTA has enjoyed such broad support in so many regions of the world that I admit even I was surprised by this. (I’ve been known to watch jealously as birders made friends with politicians because of the luxuries afforded by that standard.) Saving birds is usually much easier than saving beavers. Both sides of the aisle have often acted like a friend to birds. I guess birds don’t build dams and they usually fly somewhere else before they get too annoying. Audubon has never been the Sierra Club – nor had to be. They are polite and mind their manners working with industry and big business to help winged creatures they care about. 

Until now.

Announcing that business has a permanent ‘open season’ on birds is a huge deal for birds AND humans. I have to say I’m curious how this will affect the ‘polite’ birders of the world. Maybe they’ll get a little more noisy and start to sound more like the people who protect beavers or coyotes.

I know if it had happened years ago PGE would have fired those biologists and been happy to pocket the money. Same with the least tern population they had to count at the powerplant where Jon worked or the peregrines that nested on the smoke stack.

I can’t help but think that any industry that doesn’t have to take worry about birds today, is an industry that won’t worry about us tomorrow.

Today I have a pair of schizophrenic beaver news stories to ‘catch up on’. So we will go from the sublime to the ridiculous really fast,. Let’s start with north central Washington where beaver dams are considered SO helpful, a bunch of people are building them.

Human-built ‘beaver dams’ restore streams

Beavers are a critical asset in Washington, assuring that healthy riparian zones are maintained, especially in the dry climate east of the Cascades. Beaver dams and ponds support native vegetation and wetlands along streams, trap sediment, recharge groundwater, and improve water quality. Over the last two centuries, these benefits have been lost in many watersheds, following human development, beaver removal, channel deepening, and other impacts.

n 2015, the Okanogan Highland Alliance (OHA) was awarded a grant to restore a reach of Myers Creek, through Ecology’s Water Quality Financial Assistance Program. In the 1990s, Myers Creek was damaged in a major rain-on-snow event, which caused unusually high stream flows, deepening the creek, leaving vertical cut banks, and draining nearby wetlands.

Where beaver ponds had once provided grade control and covered large areas of the floodplain, the now-drier soils began to favor invasive plant species. The understory is now dominated by reed canarygrass (Phalaris arundinacea) and Canada thistle (Cirsium arvense), further suppressing growth of native sedge and forb species. The only remaining native riparian species still easily found in the project area is gray alder (Alnus incana), with a few isolated willow (Salix spp.) plants.

Developed by Michael Pollock (NOAA) and colleagues, BDAs offer a low-cost, simple, and easily scalable technique for mimicking beaver dams. They reduce stream velocity, induce lateral channel migration, and cause rapid aggradation of the streambed, which reconnects the floodplain so it can once again support riparian vegetation.

The long-term vision for BDA projects is that beaver will once again maintain dams to provide local grade control, floodplain connection, and wetland habitats to support a diverse flora and fauna. Sometimes partners like the Okanogan Highlands Alliance, the Washington Department of Ecology, along with many others, just have to help give them the boost they need.

And if you try real hard the good fairy will make you a REAL beaver dam and you will get real beavers to take care of you with no grant funding needed at all! Amazing huh? Maybe these stories DO go together after all. Maybe it’s a reverse case of “Love the sinner hate the sin” kinda thing. Only what gets loved is the dams, and what gets hated is the hero that makes them.

Contrast this story with Martin county in Minnesota where they hate beavers SO much they are raising the bounty on their heads from 20 per trapped beaver to FIFTY,

 County tackles gnawing problem

FAIRMONT — The beaver population in Martin County has been on the rise, causing no end of trouble for area farmers.

In December, Martin County commissioners increased the county’s beaver bounty from $20 to $50 per beaver, in an effort to alleviate the issue. According to drainage administrator Michael Forstner, this was necessary because of the low value currently in the market for the pelt.

Paul Grussing, a local trapper utilized by the county, explained the issue and was able to share some insight into the trapping process.

“The previous bounty was $20 for each beaver; at that amount it costs trappers money to trap them,” he said. “Trappers refused to trap them, resulting in a large increase in the population of beavers in Martin County. Traps and lures for beaver trapping are expensive, plus it is hard work.

“The population is quite high in our county, and beavers tend to build their dams in hard to reach areas. Most of my calls begin in September when farmers start their harvest. They see damage to their crops and dams being built.

You poor little snowflake, trapper Paul. Killing beavers is SO hard (and damp) and it’s winter ya know? Good thing you have the county supervisors by the short and curlies and can pry 50 bucks out of their palms for each beaver you take. That means you get several hundred per family. You’re RICH! Hmmm, come to think of it, maybe the bounty doesn’t count sub adults so you just leave the kits to die.

I really, really hate Martin County.

As far as Martin County is concerned, only beavers trapped within a drainage system or within one-quarter mile of a drainage system outlet will be accepted for the bounty,

And tell me, wise ones of Martin county, how, exactly, will you know?


The smith canal takes water from the San Joaquin river in to the interior of Stockton to feed Yosemite lake just south of the University of the Pacific.   It was originally created as a passage way for barge ships carrying or picking up agriculture to and from the region. It is now lined with homes and docks for pleasure boats. American legion park houses the old barge turn around point which is now called a ‘lake’ and lined with trees for recreation.

Gee, I wonder if anyone we know is enjoying those trees.

Fitzgerald: A modest proposal for smith canal

Beaver or beavers unknown are gnawing down trees around the lake in American Legion Park.

Mark Farnsworth, who with wife Liz spotted unmistakable beaver chew marks while walking their dog, said he believes the beavers are not building a dam but a lodge.

“These guys don’t have a stream to block,” opined Farnsworth. “They’ll build a den down lower.”

Beavers build DIY dams on streams to surround their mud-and-wood lodges with a pond as protection from predators. They also eat underbark. The North American Beaver used to be so prevalent around Stockton that city founder Charles Weber nicknamed Stockton “Castoria,” after the beaver’s Latin name, Castor Canadensis.

“We’re unaware of that issue happening,” stated Offi

cer Joseph Silva, spokesman for the Stockton Police Department, which includes the Animal Services Division.

Silva added, “Our Animal Control officers are only equipped to deal with domesticated animals.”

As fate would have it, there’s a long-running controversy over a flood control gate proposed for nearby Smith Canal, which feeds the lake. Perhaps, instead of spending millions, flood control officials should just step back let nature take its course.

Hmm. Isn’t that a very interesting column? Mr. Fitzgerald thank you! Although being in Stockton which depends so dearly on its levees, the odds of these or any beaver being allowed to do their work is zero percent. If once upon a time the area was so full of beavers it was nearly called “Castoria”, that is because it was so full of marshy water and reeds there was little space to build anything at all. The creation of levees divided up the town into actual land and actual water, and the area guards those levees with its very life – for a good reason. Their great worry is that a beaver or muskrat wikl burrow into a bank, weaken the levee and send the whole place underwater. They spend considerable time and money every year trapping out whatever threats they can find.

Which is why I like this article so much. If there’s one thing folks from Stockton hate more than beavers, its wasting their hard-earned money.  Telling them they could save some by letting these beavers live will likely lead to some interesting head-scratching.

Last night was an awesome beaver advocacy battery recharge. The raviolis were delicious, the company was lively, and the wine was free-flowing. To start the evening everyone took a little field-trip to Susana Park to see the site of the new festival next year. There was much delight to imagine where tents and trailers could go and how the park would look with a giant chalk beaver pond in the middle.

There are a precious few things that make you feel like the beaver decade is starting out on the right foot – er paw. But this was definitely one of them. 


Happy boxing day! Supposedly if you’re lucky enough to have servants they get the day off today and you get cold roast beef sandwiches and reheated tea. That sounds like a pretty great tradition to me.

I hope you don’t need the day off because there is work to do and beaver mysteries to ponder. Starting with the mystery of the beaver food cache. Which I realized this week I know less about than I should.

Beaver Cache: Deborah Hocking

Now this fine illustration by Deborah (the artist who made our bookmarks last year) shows the cache as I i basically imagine it. Leafy branches bedded into the soil, underwater where beavers will have access to it when the water surface freezes. As far as we know our beavers never made a food cache, and had no need to, because Martinez was well out of the freezing zone.

But in following the Port Moody case, where they get a dusting of snow occasionally but the water never freezes, I’ve realized things aren’t entirely clear to me. The city reported that the photo of the beaver in the drain clearly showed it’s “food cache”. But why would a beaver need a food cache where it never freezes? And how would a food cache that’s above the water line be of any use if it did freeze?

Judy says she has watched the beaver sit again next to his pile of sticks and choose which one to eat.  Is this a food cache? Again, why bother if it’s not going to protect the animal from freezing?

There aren’t may photos of food caches online, which I guess means that they are usually underwater or mostly underwater. But I was able to find a few.  I suppose there are beavers in ‘in-between zones’ where it sometimes freezes or has occasionally frozen.

Come to think of it, there’d be zero chance to learn your lesson if you didn’t make a cache when you needed it. Because you’d be dead of starvation and your children would be dead before they could ever learn anything for next year. Maybe since it’s such a high risk situation all beavers keep a food cache?

This is Paul Ramsay’s photo of the beavers at Bamff where it also doesn’t freeze solid. You can clearly see the sticks. Clearly above water. Where it would be absolutely no use to them to have sticks if it did freeze solid. So what’s up with that?

Apparently the cache starts with visible material, then sinks and gets filled in below as the work goes on. In fact it is even suggested that beavers put the good stuff where it won’t freeze,

Well, I can promise there was never a ‘floating raft’ of food anywhere in Martinez. Maybe freezing lightly triggers the behavior? If our beavers had been moved to the sierras would they start caching food?  Research says that when beavers from big rivers are moved to little streams they automatically start building dams, even though they’ve had no practice.

How far from the snowline does a beaver need to be before it doesn’t bother with a food cache? Do beavers  in Jackson make a food cache? In Ione? In Sacramento?

There may be something very specific that triggers caching behavior. It can’t be the presence of ice because by then would be too late in the season to make one. Maybe frost?

I wonder what it is? Think of this as a mystery-in-process, because I don’t have the answers and I very much doubt anybody else does. 

I must be getting easier to please because this whimsical article from National Geographic mostly satisfies me. Asde from the silly headline and a few wise cracks, its mostly accurate. I especially like the part when they say that beavers have a special grooming PAW on their back foot.. heh heh heh A Five footed beaver?

Beavers Have Vanilla-Scented Butts And More Odd Facts

“Beavers can change the landscape like almost no species other than humans,” says Glynnis Hood, wildlife ecologist at the University of Alberta’s Augustana Campus and author of The Beaver Manifesto.

The famously busy mammals build elaborate homes, which are called lodges when they are in open water and very visible, says Jimmy Taylor, research wildlife biologist with USDA’s National Wildlife Research Centre and Oregon State University.

They’ll also literally dam rivers. The largest beaver dam ever found was a half-mile long in Alberta’s Wood Buffalo Park—quite a feat for 27-kilogram animals. Hood and colleagues have also found that open water increases ninefold in areas where beavers were present.

Beaver activity can be good for the environment—increasing open water can lessen drought and also widen wetlands—in some cases by nearly 600 percent.

No kidding! Beavers are actually good for the environment? Get out!

It may be surprising to some, but “not all beavers build dams,” says Taylor. Beavers can live wherever there is persistent water, but sometimes their native river is too big to dam.

But they’re fine as long as they have an area to build their lodge, like a riverbank, food, access to mates, and water that allows them to escape from predators—the reason they build dams in the first place.

These family-loving animals were thought to be monogamous, but a 2009 genetic study of two populations in Illinois suggests the species “may be opportunistically promiscuous.”

“The pair bond is still there, but that male is sharing his genes with other females as well,” Taylor says, so they’re “socially monogamous but sexually polygamous.”

Sounds like something you’d hear in “divorce court,” he quips. Family bonds are strong, though, and male and female beavers will fight unrelated beavers to the death over territory.

Beavers are tramps! Who knew? At least you took the time to go and talk to the experts like Glynnis and Jimmy. Next time call ME and I’ll tell you the truth about that ‘special paw’ beavers have. Bwahahaha,,,,

Their tails don’t need maintenance, but their fur is another story. In doing so, the mammals keep air spaces in their warm undercoat and distribute their outer fur with castoreum oil, which they produce to scent mark and waterproof themselves.

“They have a special grooming paw on their hind foot, like a little split toenail,” Hood says, and they “spend almost 20 percent of their time grooming” themselves and each other.

Ohhh I wish I was at the PC because I would deadly LOVE to make a graphic of a beaver with a special grooming PAW that comes out of his back foot….Maybe one of you with photo shop talents can fill in for me for now.

Still, we have to give Liz Langley a B- for an article that is mostly accurate. The video isn’t bad either. Enjoy!