Archive for the ‘Beaver Behavior’ Category

And beavers for all

Posted by heidi08 On October - 30 - 2014ADD COMMENTS

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 - 2014ADD COMMENTS

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?

The Un-abandoning

Posted by heidi08 On October - 18 - 2014Comments Off


The previous photo reads: In this Sept. 12, 2014, photo, a tagged young beaver explores water hole near Ellensburg, Wash., after he and his family were relocated by a team from the Mid-Columbia Fisheries Enhancement Group…

I worked very hard to track down Melissa Babik after I saw this photo. Sinceher email wasn’t listed online it meant looking up the group she worked with and using their format from the listed emails to speculate about hers.  After a few false starts I cracked the code and wrote her to ask about the possibility of a leftover beaver. In the mean time, I even quarreled with beaver champion Joe Wheaton who politely admonished me for complaining about one abandoned beaver when Yakima was generally doing such a good job promoting beaver benefits. I respect Joe very much, and don’t want him to see me as some beaver-eco-terrorist – but leaving behind family is the opposite of what I want for beavers. I worried and fussed about this for more days than I will confess, thinking about the difference between what it means to be a beaver advocate (which is quite rare actually) and a “beaver benefits” advocate (which is getting to be much more common).

Then yesterday Mel wrote me back. And guess what she said? She said this photo was taken in his new location AFTER the entire family was moved. And she added:

We work hard with the best possible techniques to capture entire family units. We moved 7 beavers total in this family that would have been lethally removed. We trap for a minimum of 5 consecutive nights with no fresh activity to ensure we have the entire colony (on average this means we trap for a minimum of 2 weeks at a site but generally longer). Often we’ll go back after the sites “cools” and try again. It is sad to leave members behind and with their strong social bonds we know this limits our success.

Isn’t that GREAT news? No beavers left behind and at least 5 days of no activity before the team moves on – which often takes two weeks! I can’t remember a time I’ve been happier to be wrong, and I asked Mel for permission to share it with you so you could be happy about my wrongness too! For some reason this sound track is playing in my head.

Thanks for reading so carefully.. another misinterpretation in this generally well written article is that ~50% of our relocated beavers get preyed on our go back to their colonies. When in fact what I said was they are unaccounted for: SOME may get preyed upon (we’ve never seen evidence of this but know it happens), one we know went back to his colony, and others we are slowly finding elsewhere in the headwaters doing great things!

Again thanks for asking these questions and clearing up misconceptions! We appreciate the work you do to educate folks about beavers!


 This is all fantastic news and I couldn’t be happier!  Careful of beavers and their delicate family systems! I sent it right away to Joe who I had already repaired things with. He was thrilled to have the data to back up his positive view. This morning I will send it to everyone I contaminated with my previous gloom because they deserve to have their reputation restored. They are spreading good beaver cheer all over the country, and even if it’s not QUITE as wonderful as keeping the beavers in town, they are doing it responsibly! (I just saw an article about them yesterday in the Idaho Statesman).

I have been such a big scrooge about the Yakima good news that I feel you might deserve this clip as well. Maybe its the looming season ahead, but I can’t resist.

Beavers Far and Wee

Posted by heidi08 On October - 14 - 2014Comments Off

Beaver fence aims to stop pathway flooding in Fish Creek

A beaver appears to be missing a paw from a trapping mishap in Fish Creek Provincial Park. (Ingham Nature Photography )

A beaver appears to be missing a paw from a trapping mishap in Fish Creek Provincial Park. (Ingham Nature Photography )

Calgary officials are trying out a new way to manage beavers that are causing problems in Fish Creek Provincial Park.

The rodents keep packing mud and logs against a culvert in a city-owned storm pond. If left, the dam would cause the pond to overflow and flood a popular pathway.

In the spring, the city’s water services department is going to install something called an exclusion fence — a trapezoid shaped fence made of wire that prevents the beavers from plugging the culvert.

The city used to deal with situations like this by trapping and killing the beavers, but it reviewed that policy after an incident in July. A beaver got caught in a trap, but didn’t die and was spotted struggling to free itself.

Fish Creek Park Beavers

The area in Fish Creek Provincial Park where city officials tried to trap and kill the beaver over concerns it would flood a bike path. (Carla Beynon/CBC)

Upset animal lovers launched a petition to stop trapping in the city. That prompted the review, which revealed that debris got caught in the trap, causing it to malfunction. Since then, the city has been working with the Association for the Protection of Fur-Bearing Animals to come up with non-lethal alternatives.

“We want to go a different route so we don’t actually have to kill beavers,” said water services spokesman Randy Girling. “We don’t want to be known as killers or anything like that. We want to do the best we can for the wildlife in our parks.”

Hurray for Adrien and Fur-Bearer Defenders! They managed to convince the good folk of FCPP that it was better to try something new than claw their way out of any more bad press and public wrath. Adrien says it was hard, hard work. Like pushing a grand piano through a transom. But they persevered and were granted permission to install a beaver deceiver  now. Gosh, I’m so old I can remember when Adrien installed his first leveler!

Sniff, they grow up so fast.

Speaking of the long arm of beaver defenders, I got an invitation this morning to present at the San Pedro Valley Park in Pacifica on beavers. A month after I’ll be talking in Auburn. That’s 133 miles apart for beaver defense. 1670 if you count Utah and Oregon. And Cheryl just visited Big Break in Brentwood where she snapped these videos of our work at the visitors venter!

Pretty cool to be long-range beaver preachers!

The Trail from Utah to Martinez

Posted by heidi08 On October - 13 - 2014Comments Off

Hot of the presses I just got word from Mary Obrien that the BRAT (Beaver Restoration Assessment Tool) has just been completed for the entire state of Utah. The complete report and maps are here and I will put a permanent link on the margin alongside the last amazing thing Utah did for beavers, (and the one before that). Here’s a little excerpt  from the executive summary.

This report presents the development and application of the Beaver Restoration Assessment Tool (BRAT), a decision support and planning tool for beaver management, to analyze all perennial rivers and streams in Utah. The backbone to BRAT is a capacity model developed to assess the upper limits of riverscapes to support beaver dam – building activities. Both existing and historic capacity were estimated with readily available spatial datasets to evaluate five key lines of evidence: 1) a  perennial water source, 2) availability of dam building materials, 3) ability to build a dam at baseflow, 4) likelihood of dams to withstand a typical flood , and 5) likelihood that stream gradient would limit or completely eliminate dam building by beaver. Fuzzy inference systems were used to combine these lines of evidence while accounting for uncertainty.

CaptureWith this announcement came a note from Mary that two stalwart Utah beaver champions are coming out to San Rafael for the annual Bioneers conference this month. They are going to a soils workshop and would like to meet Worth A Dam and the beavers if at all possible. For the past 5 years they’ve been hard at work letting beavers turn the tiny incised trickle on their land into this beauty. Their beavers have survived  the last 5 years on mostly cattails because there are no trees to speak of!




P1090548And speaking of beavers eating cattails, here’s a video Rusty sent this morning of  a Napa beaver doing just that. The green water is pond weed/algae and don’t worry, I just read this morning that  cattails are VERY nutritious.

50 states of beaver

Posted by heidi08 On October - 12 - 2014Comments Off

Old Fort fifth-graders learn all about water-dwelling rodent

 It isn’t every day that Old Fort fifth-grader Makayla Evans gets to dress up like a beaver.

 Garbed in goggles, a blanket, sound-proof headphones, a trash bag and a pair of gloves, the fifth-grader stood in front of her classmates wearing items that represented different traits the rodent found all across North Carolina possesses.

 “I’m going to hand Makayla this small canister of oil,” said Lake James State Park Ranger Kevin Bischof. “Can anyone guess what that represents on a beaver?”

 “It’s what keeps their coat waterproof,” said one student as Bischof continued handing Evans more items to go with her makeshift costume.

 Bischof’s presentation was part of an hour-long lesson in Joanna Graham’s science class at Old Fort Elementary, which was designed to help students better understand the American beaver.

Now we’re all read about the park system educational brilliance where they dress a kid in a fur coat and put on flippers and say ‘you’re a beaver’. But mind you this is North Carolina, which (if we’re being kind) has a fairly conflicted relationship with beavers, so we are really haooy 5th graders get beaver ed. But this blew me away:

“The beaver is a keystone species,” said Bischof. “If you remove them from an environment, it drastically changes. It takes constant maintenance to keep up a dam, and if a beaver is removed from the area then their dams will eventually deteriorate and change everything in the area where they’ve been.”

You can almost here the unspoken message “So tell you’re dad if he blows up that beaver dam it will be bad for everything”, can’t you? Of course I wrote Kevin right away. And our beaver friends in North Carolina to introduce them. Every now and then I start to think the landscape for beavers is changing all over the united states. Which is a pretty nice thought to have. Oh, and I sent along these:

archbrochurecharm 008


Researchers Say Beavers Are More Than Simple Pests

Yakima beaver relocation was on Scott Simon yesterday of NPR. More good promotion of beaver benefits, although I hate the headline. It reminds me of that scene in Tolkein’s the Two Towers, where the hobbits stumble on the oldest forest.

” What a pity! This shaggy old forest looked so different in the sunlight. I almost felt I liked the place.
‘Almost felt you liked the Forest! That’s good! That’s uncommonly kind of you,’ said a
strange voice. ‘Turn round and let me have a look at your faces. I almost feel that I dislike you both, but do not let us be hasty. Turn around!’ “

In addition to the usual beaver beatitudes there are a few choice quotes that I will offer without comment.


Click to Listen

We try to catch the whole colony because beavers have incredibly intense family social bonds. So without taking the whole family colony, they’re more likely to go right back to where they once were caught in searching for their family members.

[Regarding their naming of beavers] It helps us bring light to sometimes sad instances where family members may have gotten lost behind.



And now that we’re back from vacation I’m starting to think about Halloween decorations. We’re so lucky we may have just the thing! What do you think, too scary?



Vær så god

Posted by heidi08 On October - 8 - 2014Comments Off

The Yakima “happily ever after” beaver story made the rounds yesterday, on ABC, Fox, Yahoo and the Huffington Post.  I am thrilled that the story of beavers doing environmental work is having a news cycle. I am less thrilled that the meme of relocating beavers is getting thrown about and teaching the world to solve problems by moving them.

(And I’m jealous.)

I received some awesome news from very close to home that I am forbidden to share yet. So I will give you some great news from rather far a field instead.  This is being described as the longest beaver population study ever, and they have the publishing record to prove it. One of the researches, Christian Andre Robstad posted on it on the Beaver Management Forum.

I wasn’t exactly sure what they were studying, and Christian sent me this. I’m imaging some Google translate may have been involved?

Main research questions

Why are some individuals more successful in surviving and reproducing than others?
What affects the temporal and spatial variations in the landscapes of fear, nutrition, and fitness?
How do variations in territoriality affect the mating system and individual fitness?
What is the role of chemical signals in territorial defense, recognition and discrimination?
How do humans and their activities (e.g. hunting, climatic change) affect the fitness (i.e. survival and reproduction) of wild animal populations?
The scientific backdrop for LEBE! is provided by the Scandinavian Brown Bear Research Project and the Norwegian Beaver Project (NBP). The SBBRP is one of the world’s largest and longest ongoing large mammal projects (1984-today), with a very high scientific output (>180 publications in international peer-reviewed journals, including Nature and Science). An individual-based long-term data set of >800 captured bears, biometric measurements as well as genetic and physiological samples from >2000 captures, > 2million re-locations of radio-collared bears, and data from >2500 shot bears form the basis of the SBBRP. Assoc. Prof. Andreas Zedrosser is one of the lead scientists of the SBBRP, as well as a member of its steering committee.

The NBP is one of the world’s largest and longest ongoing large rodent projects (1997- today), with a very high scientific output (>80 publications in international peer-reviewed journals). An individual-based long-term data set of >400 captured beavers, biometric measurements as well as genetic and chemical samples from >1000 captures form the basis of the NBP. The NBP is unique in Europe, as it is one of very few projects carrying out behavioral experiments with large wild mammals. Prof. Frank Rosell is the leader of the NBP.

Both projects provide long-term individual-based data sets unique in a world-wide context, which are explored in relation to the main research questions in LEBE! The main model species in LEBE! are the brown bear and the Eurasian beaver. The majority of our research and publications deal with these species and will continue to do so in the future. However, in addition we also work with other species as well, such as dogs, marmots, badgers, brown trout, ground squirrels, root voles, Mediterranean monk seals, and chamois.

Central research disciplines

Evolutionary ecology
Behavioral ecology
Laboratory members

Heads of laboratory