Archive for the ‘Beaver Behavior’ Category

A Call to Action

Posted by heidi08 On November - 22 - 2014ADD COMMENTS
Rett Davis
Published: Friday, November 21, 2014 at 05:28 PM.

Question: Coyotes howl, ducks quack, and deer snort. What sounds do beavers make?

Answer: The only sounds I have heard from a beaver are when they slap the water with their tail. It is a rare day that you walk up on beavers unnoticed. They have a keen sense of either hearing or sight. Your question prompted me to contact my wildlife biologist friends.  Both Harlan Hall and Jason Allen agreed they do not have a distinct call. When caught in a trap they will growl and hiss. But most animals do that. They did comment that puppy like sounds can be heard coming from their lodge. A lodge is where a beaver family dries out and sleeps. It is there that they are protected from the weather and their predators.  Swamps and all the animals that inhabit them surround their lodges.  You are welcome to pursue this answer. Let me know what you find out.

Raise your hand if you think Mr. Davis is correct? Well the poor man only talked to trappers for research so we probably shouldn’t blame him. We should invite him to come to Martinez from North Carolina and have a listen around June, when kits are whining away and yearlings are starting to get jealous. Then he will find out how very wrong this answer is.

Once upon a time, an entire age ago, I didn’t know beavers made noise either. And I thought they might possibly eat fish. I remember standing at Starbucks looking into the creek just after the city said they should be killed and thinking, do the people who want them dead even know about that noise? Have they ever heard it?

And then, if I let these beavers die, when will I ever hear that sound again?

So that plaintive whining became my call to action.  I thought, well I’d give the issue a weekend and try to save them. Then a week. And then, well you know the rest.

For beaver, though it hath no tongue, will speak

With most miraculous organ

Hurry! Only 12 days left to call WS liars!

Posted by heidi08 On November - 18 - 2014Comments Off

Well, I’m sure you’ll have plenty of other opportunities, but this is an important one. Before we get down to work and roll up our sleeves, let’s have dessert first.

Searching for beavers on the Quabbin Reservoir’s restricted Prescott Peninsula

About 20 DCR biologists and volunteers stomped to shake off the cold Sunday morning, standing in a ring outside a small shack on the Prescott Peninsula as Clark set the plan for the annual beaver survey. Teams would split off, tramp through the woods to follow their respective streams, take down data on any active beaver lodges, then return to the shack for lunch.

Beavers were non-existent in Massachusetts for more than a century due to hunting and trapping, plus elimination of habitat. After the valley was flooded in the late 1930s, the beavers returned.

Clark said that after the beavers came to the reservoir, the population followed a pattern typical of reintroduction — explosive growth, followed by a crash as the habitat is oversaturated, then a steady leveling off.

No way, are you suggesting that the population actually regulated itself? Without trapping? Even when the Massachusetts voters imposed new restrictions on trapping in 96 and the population was supposed to explode? This is pretty outlandish stuff. Just how long have you been collecting this spurious data?

The first Prescott survey was held in 1952. The survey has been annual since the early 1970s, and some of Sunday’s searchers have returned every year for 30-40 years.

Holy Guacamole Batman. You mean they have 62 years of data on beaver population? And the effect of conibear restriction is somewhere in the middle? You know a statistician worth his pocket calculator could easily whip those numbers into a regression analysis that disproves the accepted lie about beaver population exploding after the new rules were applied? You do know that, right?

Well, maybe the reporter got that wrong. He seemed really distracted by the meat balls. He does say that people aren’t normally allowed in the area because it’s in the watershed. Ahem. (News flash:Every place on this planet is part of a watershed. Just so you know.)


Everyone ready? It’s November 18th so that means you still have 12 days left to tell Wildlife Services that their rodent management plan is ridiculous, oblivious  of the environment or science, and barbaric in the extreme. But those are just my words. You’ll find your own. Here’s Mike Settel from Idaho talking about what’s needed.

In Wildlife Service’s newest justification for ridding us of beaver you can find that bit of humor and others in a recent request for public comment on Wildlife Service’s “Aquatic Rodent” EA for North Carolina.

Don’t attempt to e-mail your comments because, according to their deputy director for environmental compliance Alton Dunaway, receiving comments only by FAX and snail mail will “modernize” their public involvement process. I recommend Faxing comments to (919) 782-4159…However, an e-mail you may find useful is for that of the author, Barbara Schellinger. 

Even though it is a North Carolina document, the rationale proposed sets a precedent for mis-information and obfuscation regarding wildlife management. Please FAX your comments and request that WS includes non-lethal mitigation as beaver solutions, provide current data showing beaver harm salmonids, and prove that beaver dams increase sediment pollution (there are other spurious claims that are suspect or dated, but you should read those for yourselves). Regards, Mike

Thanks Mike for putting us on the right track. Remember, what they get away with in North Carolina will become precedent everywhere. I will share just a little bit of their ignorance, but you should really go read the report for yourself here:

The Wisconsin Department of Natural Resources guidelines for management of trout stream habitat stated that beaver dams are a major source of damage to trout streams (White and Brynildson 1967, Churchill 1980). Studies that are more recent have documented improvements to trout habitat upon removal of beaver dams. Avery (1992) found that wild brook trout populations improved significantly following the removal of beaver dams from tributaries of some streams. Species abundance, species distribution, and total biomass of non-salmonids also increased following the removal of beaver dams (Avery 1992).

Beaver dams may adversely affect stream ecosystems by increasing sedimentation in streams; thereby, affecting wildlife that depend on clear water such as certain species of fish and mussels. Stagnant water impounded by beaver dams can increase the temperature of water impounded upstream of the dam, which can negatively affect aquatic organisms. Beaver dams can also act as barriers that inhibit movement of aquatic organisms and prevent the migration of fish to spawning areas.

Wow. Give it up for the USDA and author Barbara Schelllinger who was willing to dig back through 47 years of research to find the  completely bogus paper she just knew to be true! This woman is no slacker when it comes to bravely lying about beavers. Good lord, the letter almost writes itself. Although I personally feel that Issue 7 deserves the lion’s share of our attention.

Therefore, the breaching or removal of a beaver dam could result in the degrading or removal of a wetland, if wetland characteristics exist at a location where a beaver dam occurs. The preexisting habitat (prior to the building of the dam) and the altered habitat (areas flooded by impounded water) have different ecological values to the fish and wildlife native to the area. Some species may benefit by the addition of a beaver dam that creates a wetland, while the presence of some species of wildlife may decline. For example, darters listed as federally endangered require fast moving waters over gravel or cobble beds, which beaver dams can eliminate; thus, reducing the availability of habitat. In areas where bottomland forests were flooded by beaver dams, a change in species composition could occur over time as trees die. Flooding often kills hardwood trees, especially when flooding persists for extended periods, as soils become saturated. Conversely, beaver dams could be beneficial to some wildlife, such as river otter, neotropical migratory birds, and waterfowl that require aquatic habitats.

beaver in barDingDingDing! I found the opening! (Well, one of many actually.)  See in their effort to say “it’s a wash, really” beaver dams HELP some species sure, but they HARM others. So getting rid of them is a zero sum game with totally justifiable consequences. Just take the darter for instance!


Maybe we’re the only ones that remember there’s this famous case from Alabama in 2008 where the city of Birmingham was sued by The Department of Conservation and Natural Resources (among others) for upwards of a million dollars over removing this beaver dam that was protecting  thousands of the rare endangered watercress darters. In the end the case cost the city some 4,000,000 dollars and dragged  out in court over 4 years. Am I ringing any bells, does this sound vaguely familiar?

The city “knew or should have known that removing a beaver dam and surrounding natural structures would potentially disrupt the water level of the Basin and its inhabitants,” the agency claims.

CaptureDam [sic],  this is gonna be fun. If you want to share your letters, send them to me and I’ll make sure they’re visible. I’m sure WS is hoping they can make it all the way to November 30th without hearing from you. Let’s disappoint them, shall we?

You’ve heard of the lion in winter, right?

Posted by heidi08 On November - 17 - 2014Comments Off

There’s something about winter that gets sport writers whimsically musing about beavers under the snow. Maybe because its suddenly too cold to go fishing or just because they’re jealous of the fur. I don’t know why, but trust me, it’s a thing. This is from the Idaho Statesman.

Roger Phillips: Idaho snow shows nature that often hides

Still don’t know all the details, but when you see a freshly eaten tree trunk and a slide with packed snow down to the water, it’s obvious there’s been a beaver working within the last few days, and likely at night.

I also saw a U-shaped path between two ponds where the beaver crossed enough times to compact and melt the snow into a little bobsled run.

 Heck, maybe it did it for fun.

 Ahh beaver tracks in the snow! Something Martinez will surely never know. Although I have seen historic photos of a snow covered main street from the early 1900′s. I suppose it could happen! Any more winter musings out there? This is from Toronto.:

 People should envy the beaver for its winter set-up – a cozy cottage stocked with wood, food and family

Beavers, on the other hand, have an enviable winter set-up. The largest rodent in North America, beavers have an impressive work ethic.  Second only to man, beavers change the environment to fill their requirements.

 Unlike man, beavers only build habitat-changing dams when they need to increase water levels for food storage and protection from landlocked predators. And beaver dams don’t only benefit beavers; they also play an important role in creating, maintaining and restoring wetland environments.

 In the winter, the beavers rely on an underwater food cache they stock with wood before temperatures drop. If the water freezes they still have access to food. Beavers mate for life, and have up to six kits a year. The young stick around for two years before leaving to set up their own lodge. That’s plenty of company to ride out a long winter.

Well yes, beaver accommodations are enviable. As is their fur. Which was envied so much they were nearly rendered extinct. I guess the point of your article is that we should all be cozy like beavers? I can’t say I disagree. This last one is from Minnesota and its actually well-written. I can’t think if anything flip to say about Larry Weber’s article which, considering I know the plot, was surprisingly engrossing.

Beaver lodge and pond covered in snow.

A visit to a beaver pond

The resident beaver family has been very busy lately. The woods at the shore is scattered with chewed-off stumps of largely aspens, but I also note some willows and poplars. The fallen trees, mostly small, less than 6 inches in diameter, lay on the forest floor. Once the trees are downed, branches are bitten off and taken to the lodge out in the water. The largest ones are placed on the lodge to add more of a fortification and protection for the beavers.

 Protection is from the winter weather, but also predators. In like manner, some stout branches are used to strengthen the dam. This wood, plus rocks and mud, will make this structure solid and keep the water level of the pond high enough to allow the beavers to swim about as they enter and exit their house from below without being frozen shut. In recent years, I have found a few nearby ponds where winter cold caused the ice to form deep and block the beaver’s swimming and feeding beneath the ice.

 But the beavers are doing much more than fortifying the lodge and dam for winter. They are also preparing a food cache to get through this time.

 All through the warm weather, they were able to swim ashore to cut and snack on nearby arboreal meals. Ice will curtail such activities and so the beavers use saplings and smaller and thinner branches of their cut trees to stash food in preparation for the long freeze-up. Now, in the freedom of no ice, they drag the branches back near the lodge where they store large numbers of this winter food. This cache of twigs and branches will freeze in the ice, but is close enough so that the food is accessible as the beavers swim under the ice and bite off morsels for meals.

It’s a long time from now until the thaw next spring and so the beavers try to store enough woody food to last this whole frozen time. And from what I see here today, in mid-November, they appear to be doing just that.

It is so nice to read something from someone who knows both how to write and how to observe. Thanks Larry. And thanks beavers for being so hardy that you make it bravely through the winter on your own. At the moment we’re just hoping that it will rain a little in California. Then we’ll start worrying about the snowpack.


Posted by heidi08 On November - 11 - 20142 COMMENTS

Beavers are busy preparing for winter

With the arrival of killing frosts, animals have gone into high gear preparing for the tough conditions soon to follow.

 Those who are feeding birds have observed their sunflower seed supply rapidly dwindle as Blue Jays repeatedly fill their crops only to fly off and cache their loads. Gray Squirrels are also busy, frantically seeking the last of the acorns to stash in the ground.

 And Beavers are busily harvesting trees as they build their winter stores.

The author of this article, Michael Runtz, is a friend to wildlife and to beavers in particular. We’ve connected in the past and corresponded about his work. He’s been photographing and watching beavers for 20 years, and his lovely photos were featured in the recent beaver documentary on PBS. The last I heard from him his book on beavers was due out any minute. But I guess while we wait for that we should savor this interesting fact.

Surely the presence of alders in food piles is sufficient evidence that Beaver’s prefer them in their diet?

 Actually, it is not. When food piles are examined, the surface portion often contains inedible items such as cedar and fir branches. And previously enjoyed (barkless) branches also adorn them.

 The most edible items are actually hidden deeper under the surface of the pile where they will not become locked in ice. That is where poplar and willow branches reside; these will be extracted from the pile all through the winter.

This is worth remembering. The good beer is always hidden in the back of the refrigerator.

waterboardsThis is the Elihu Harris building in downtown Oakland. It houses some of the most essential state government offices, like the Equalization board, the Alcohol and Tobacco board, The Unemployment board, and the Water Quality control board. That’s where Ann Riley works as a Watershed Stream Protection Advisor.

One portion of the Water Quality board is dedicated to what’s called the “Beneficial Use of the state’s waters”. Which covers areas like fish and water-dependent wildlife. Riley is a huge beaver supporter and invited me to be part of her panel at the Salmonid Federation last March. Now come December guess who just got invited to talk to them about a new potential partnership with beavers?

I can’t tell you what a big deal this sounds like in my head. I immediately thought of all the things that could go wrong: I could mess up, lose my voice, my computer could break, it could be cancelled, there will be no one there because it’s the holidays, I got invited because something bad is going to happen, etc. But it doesn’t matter. Beavers are coming to the water boards.

And it’s a big deal.

WALC this way!

Posted by heidi08 On November - 7 - 2014Comments Off

I think it was 2008 when I first wrote Catherine Salvin of the WALC school at Balboa High in San Francisco. WALC stands for Wilderness Arts and Literacy Collaborative and is an outdoor-immersion-ecologically-minded splendor that is accessible to both continuation and Balboa students. As you can see it is definitely not your typical school.

Last year Catherine wrote that there was FINALLY money to get the kids here and they would like to make a visit to see some urban beavers.  I told them the viewing was better before November but this is the first chance they had to make the trek. Jon and I are meeting them tonight down town for a beaver tour, and I’m hopeful that the beavers will cooperate. With any luck they will inspire some essays or artwork and I will get to post it here! (Not to mention fostering a healthy respect for urban beavers and their contributions later in life.)

WALC student artwork

Fingers crossed that we will see actual beavers in our beaver habitat!

In the meantime I’ve been thinking some pretty fanciful thoughts. Bear with me. (Remember my day job is a child psychologist so it’s an occupational hazard.) These thoughts are about mermaids.  No seriously. Now everyone has seen the little mermaid and knows about mermaids in the ocean but did you also know that there are old stories that say some mermaids travel up estuaries to fresh water lakes? Estuaries like the Carquinez Straits? (Humphrey did it!)There is even some indication that they go to fresh water when they’re pregnant and give birth in fresh water. Which makes sense, considering salmon and steelhead go out to sea and come back to breed and lay eggs. Can’t you just imagine a mermaid tagging along beside a salmon and finding herself surrounded by cattails?img-thingMermaids have also been described as being able to swim up rivers to freshwater lakes.

And since you already agreed to come this far with your imagination,  can’t you imagine how mermaids would enjoy swimming around with beavers in their murky splendor? I mean, you’ve seen paintings of them with seals, and dolphins, so why not beavers? Visiting their underwater houses, helping with a repair or two and playing with the kits? There are numerous stories about mermaids helping humans so it’s not unthinkable to imagine they would even warn beavers about trappers or underwater snares.

In the vast entirety of the internet, where one can spend days and months looking through every possible crazy idea that is dear to someone,  there is not a single thing written or drawn about beavers and mermaids.

Until now.


Beavers and Freshwater Mermaid – Worth A Dam

And beavers for all

Posted by heidi08 On October - 30 - 2014Comments Off

Say what you want about my idiosyncratic reporting, but this has sure been ONE HELLUVA WEEK for beavers. This morning a retied librarian beaver friend sent this my way with best wishes. It was published online exactly two days ago.

Ecological engineering and aquatic connectivity: a new
perspective from beaver-modified wetlands


1. Habitat fragmentation and wetland loss due to anthropogenic causes are usually attributed to physical modifications of the environment; however, the loss of key species can compound these impacts and further reduce the connectivity of aquatic ecosystems.
2. Ecosystem engineers can play a critical role in modifying aquatic systems by altering the bed of ponds and streams, increasing water coverage and influencing biogeochemical processes within and adjacent to freshwater habitats. However, there is a paucity of research on how these organisms enhance connectivity among aquatic habitats, especially in otherwise isolated wetland systems.
3. In this study, we collected field data at natural and agriculturally impacted sites to quantify physical alterations to otherwise isolated, morainal wetlands modified by beavers, and to determine how these modifications might enhance connectivity. For finer-scale analysis, we collected and modelled bathymetric data for 16 wetlands, eight of which were occupied by beavers and eight abandoned by beavers.
4. We demonstrated that beavers actively increase the volume-to-surface area ratio of wetlands by almost 50% and that their digging of foraging channels increases average wetland perimeters by over 575%. Some channels were 200–300 m long, which enhanced the interface between the riparian zone and upland forests. A coarse estimate of soil displacement due to the digging of channels by beavers exceeded 22 300 m3 within the total 13 km2 natural area. Additional measures of wetland depth, basin complexity and basin circularity revealed other dramatic differences between wetlands with beavers and those without in both natural and agricultural landscapes.5. Exclusion or removal of beavers could limit ecosystem processes and resilience, especially in areas with otherwise isolated aquatic habitats and limited connectivity. Conversely, reintroduction of such an ecosystem engineer into areas targeted for restoration could result in significant increase in habitat heterogeneity and connectivity.Keywords: beaver channels, Castor canadensis,

CaptureBefore we even launch into the article or the full awesomeness that is Glynnis, take a close look at this graphic showing the difference between beaver-present ponds and beaver-absent ponds. They differ in average increase of perimeter by 575%. No, seriously. Because you know Dr. Hood of the impeccable credentials and methods has had her graduate students meticulously measure and GPS it twice. Check out this quote from the discussion section.====

The increase of wetted perimeter of morainal wetlands by more than 575% on average demonstrates the important role one species can play in patch dynamics, spatial connectivity and habitat creation.Complex configuration of these perimeters (Fig. 5)also increases within-pond habitat heterogeneity byincreasing shoreline complexity, cover for waterfowl(Nummi & Holopainen, 2014) and potential dispersal corridors for other species to upland and adjacentaquatic habitats (Anderson, 2013).

If there is a rock star of beaver research it is Glynnis Hood. She is thoughtful, observant, charismatic, research driven, and she loves beavers.  If I could be twenty years old again and a graduate student in ANY campus, I would pick the University of Alberta, sit in the front row, take notes in two colors and hang upon her every word.

High shoreline complexity is one of the most important factors for enhancing biodiversity in wetlands (Hansson et al., 2005). In our study, the influence of beavers on shoreline and basin complexity at the local (wetland-specific) scale was easily observed; however, this complexity was also readily apparent at the landscape scale. Beaver channels were used not only to link a wetland with its adjacent upland habitats; they also joined one wetland with another over 10s or in many cases 100s of metres. Those wetlands would similarly be joined through the same process over increasingly larger scales.

Go Glynnis go! Here’s my 2012 interview with her. Oh and this is my very favorite part of what is now my very favorite paper, proving the inherent inter-connectivity of all things:

Many of these beaver-modified wetlands (active ones in particular) had an outward appearance resembling neurons with dendritic extensions into the ‘tissue’ of the surrounding landscape (Figs 2 & 5). 

You want to know the funny thing about the word DENDRITE? (I mean besides the fact that mine are busy de-mylinating at an alarming rate.) The funny about the word Dendrite is that it comes from the word Dendron in Greek, which means “Tree”. “Dendritis” means tree-like in Greek. So those fractal neural connections in our brains were called Dendrites because of trees.

Which beavers eat.

Naturally Curious about Beavers

Posted by heidi08 On October - 29 - 2014Comments Off

CaptureNaturally Curious: Ecosystem Engineers

Wetlands are crucial — roughly 85 percent of all native North American wildlife relies on them — and throughout most of North America wetlands are highly correlated with beavers.

 When the beaver population plummeted due to fur trade in the 18th and 19th centuries, the number of beaver wetlands did as well. Today, beavers number around 6 million to 12 million, and the number of ponds is estimated to be between 1.5 million and 7.7 million. This had an enormous impact on the flora and fauna in and around these wetlands, changing the distribution and abundance of many plants and animals.


Naturally Curious: Ecosystem Engineers
Beavers are one, if not the only, species capable of changing the geological, chemical and biological properties of the landscape to suit their needs.

If you want to know why the state of New Hampshire is having such positive public support for beavers, it’s entirely because of articles like this. Mary Holland is a talented author and breathtaking photographer who donated generously to our silent auction in the past. She likes to write about beavers sometimes, but this is the most glowing advocacy I’ve seen from her yet. I’m hoping that we influenced her work in some small way. There is so much I want to share I can barely pick and chose. Make sure you click on her article  just so she gets credit for this remarkable work. Here’s a treasure hunt for motivation: there is one thing she got wrong. But only one. See if you can find it.


 Studies have shown that by increasing the diversity of habitats, beavers increase the number of species of herbaceous plants. By expanding wetland habitat, beavers provide an ecological opportunity for new plant species. The riparian vegetation — plants on a pond’s banks — not only increases in number of species, but the vegetation becomes denser as a result of beaver activity.


A beaver dam slows the current of a stream and increases deposition of nutrient-rich sediment and organic material in the water. This plays a key role in the development of insect life. The variety and density of species increases, providing more food for fish, birds and mammals.  Although one would think that the presence of a beaver pond might increase


 As one would expect, there is a shift in fish species, just as there is in insect species, as the rapidly flow ing stream is converted to the stillness and increased warmth of a pond. Studies have shown that fish species richness increases with the size of a pond, but even very small beaver ponds can have higher than expected richness compared to ponds of a similar size not impounded by beaver dams.

 Contrary to popular belief, beaver ponds have been shown to have a beneficial effect on trout and salmon populations. Loss of beaver ponds has been correlated with a significant reduction in salmon production. Beaver dams are typically not barriers to fish — they find ways of passing through them, except when stream levels are very low.

Amphibians and Reptiles

dt.common.streams.StreamServer.cls Beaver ponds create an ideal habitat for amphibians. Reptiles also fare well in beaver ponds, especially older beaver ponds. There is greater species diversity of snakes and turtles in older ponds than younger ones, but even younger beaver ponds usually have more species than undammed streams.


 A wide variety and number of mammals uses the lush vegetation around beaver ponds as food and cover. An increased production of woody plants (vigorous shoot growth at beaver-cut stumps) and aquatic vegetation attracts browsing moose and deer. Water-loving muskrats, otters, raccoons and mink frequent beaver ponds for food and shelter.


dt.common.streams.StreamServer.cls1 The creation of an aquatic habitat necessarily will attract different species of birds than a forest habitat. Significantly more bird species have been found at active beaver ponds than abandoned beaver ponds and control sites with no history of beaver occupation. Waterfowl use beaver ponds for nesting and rearing young, and as stopover sites during migration.

Mary’s Closing argument:

Humans may disagree about the advantages and disadvantages of having beavers as neighbors, but there is no disputing the fact that beavers play an important role in preserving biological diversity.

And THAT’s what the New York Times SHOULD have said. (By the way I just heard that the NYT beaver article is tracking as the 6th most emailed!)

Thank you so much Mary for singing beaver praises with such passion and timbre! We are grateful for your eloquence, talent and veracity. I’m sorry the grey lady pushed your work out of the spotlight for a whole day, but I am so thrilled to promote your work now!

And if you need a little more illustration to the argument that beavers create habitat, here’s some recent footage from Rusty Cohn in Napa showing an unexpected visitor to the beaver dam. He wondered, fox or coyote? So I sent it to the expert. This morning Camila wrote back: COYOTE!

We have been so inspired by his work we tried our own trail cam last night for the first time, but all we got was the “Lesser-spotted-Moses” hard at working cleaning up a tree so the city wouldn’t be annoyed at the beavers. Recognize this species?