Yesterday morning Mom beaver was seen chewing willow with another, mostly adult beaver that was not dad. We were thinking our three yearlings, not seen since March, had moved on to seek their fortunes. Apparently at least one of them is still around.

Yearlings “disperse” around their second year and head off looking for territory of their own. They will go anywhere from 2-30 miles away looking for a place to call home. Sometimes you hear the very strong belief that “beavers always go down stream from their parents”, but obviously if that were true by now all the beavers in the world would be in the ocean. In fact, several dissertations have been done on this subject, and it turns out that slightly more yearlings go upstream than downstream, but that the ones that go upstream are more likely to come back.

“Coming back” is an interesting thing beaver families allow. Although they wouldn’t let another beaver move into the territory, they will let yearlings come back and hang out with the colony for a while. Every family member recognizes them by their scent. Beavers are the only animal besides porcupines where the females “disperse” for greater distance than the males. This again speaks to how importantly the beaver family is a matriarchal society. It’s important to note that as unlikely as it seems, dispersal also happens over land. Beavers walk their way to freedom, and often when we are at displays or events the most prominent story we hear from strangers is that “once they saw a beaver hit by a car.” In fact, more people have probably seen a dead beaver than a live one, I guess because they stay still longer.

At any rate, one of our yearlings is in the lodge still, and whether this means he didn’t ever leave, or he’s come back to try again, we have a family of at least three, possibly more. Interestingly mom was seen swimming upstream last night, past Starbucks, past ward street and towards where the creek is under cement. Not sure what that’s about, but very interesting to ponder.

“If seven maids with seven mops
Swept it for half a year.
Do you suppose,” the Walrus said,
“That they could get it clear?”
“I doubt it,” said the Carpenter,
And shed a bitter tear.

Lewis Carrol

“Unprecedented”. “Nobody could have predicted”. “Never before”. These words keep getting used to describe the oil volcano that is busily digesting its plug at the moment. Here’s some very smart reporting showing you that this isn’t as unexpected or new as you might think.

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Last week the Winnipeg free press ran a puzzled column about why there were so many recent reports of beavers seen on sidewalks and streets. The blogger, Ace Burpee, a radio personality, wrote that he would get to the bottom of the mystery and find the answer. (He especially got my attention by writing the secret code words, ‘beavers are awesome’.)

Since we received the first phone call late last week about a beaver roaming the streets around Main and Higgins, many more have followed. I’m now up over a dozen calls and e–mails on confirmed beaver sightings on streets and sidewalks in the last week. This is bizarre. One report is intersting. The second report means we might be on to something… but once you hit double digit reports it’s officially a trend. Beavers strutting down Marion. Beavers walking down streets in St. B nowhere near a body of water. Beavers are the greatest thing in the world, but I’m concerned. There are a ton of questions here.

So I tracked down Ace at the radio station and wrote him about overland dispersal. I explained it was the ‘launching’ time for the almost two year-olds, before the new kits are born, to go and seek their fortune. While it was startling, it was perfectly normal and happened every year at this time. He was thrilled to get an explanation that made sense and posted my email on his next column. Another beaver fan in Winnipeg which is always good to know.

Photo: Cheryl Reynolds June 18, 2009

Beaver colonies are discussed as Matriarchies, meaning that the oldest beaver has the central role in colony stability and management. If the female is lost the colony will relocate and start over somewhere else. Female dispersers go farther afield than males for just this reason; they understand a colony will grow around them and they want to make sure they have adequate food supplies. Certainly we observe mom with the most important work in our colony, bearing and nursing the kits and mudding the lodge for comfort and safety.

I remember back when Mary Tappel was first advising the city and the Gazette (now two editor’s ago) reported her saying female beavers produce kits “for 50 years”. I called giggling to point out the typo, and RIchard assured me that it was no typo, but that this was what he had been told by Ms. Tappel directly. Curious about my reaction, he called her back to verify, and with some hemming and hawing she was able to shorten the number to thirty-five.

!!!!!!

For the record, beavers are sexually mature enough to breed sometime after their second year, and their entire life span is about 15 years. I was able to find record of a beaver in captivity living for 19 years, but that was the Rip Van Winkle of beavers. In ideal circumstances, a female may produce kits for twelve (12) consecutive years.

Don’t feel bad, City of Martinez. Your expert was only 76% inaccurate. The other 24% was right on the money.

I hope by now patient readers are getting a good sense of the connectedness of all things: how reintroducing wolves in yellowstone can improve forestation on the lower wetlands, or alligators nesting can make mud pools for ibis. Well here’s a great story from the Goat Blog of High Country News by Terray Sylvester of a particular researcher interested in the shrinking habitat of Sweetgale and its relationship to the decreasing salmon population.

Greg Hood is a researcher in western Washington who knows a few things about salmon habitat — a few surprising things. When Hood talks about preserving threatened populations, he doesn’t mention in-stream flows, fish ladders or water temperatures. Instead, he brings up a mostly-vanished ecosystem than once lined significant portions of the Puget Sound. It was composed of a shrub named sweetgale, tidal marshes and… beaver ponds near the seashore. That’s right, some beavers stake out seaside territory, and according to Hood, their ponds make excellent homes for juvenile salmon. Problem is, most of that tidal habitat has been destroyed over the last century or so. So little of it remains today that he thinks most people have forgotten — or have just never realized – how important the beaver ponds once were to the endangered Puget Sound Chinook.

Sweetgale (bayberry, dutch myrtle, chevalier) is a low growing, willow-resembling, and fragrant marsh cover that used to grow all over the salty creeks near the sea side. In older days they used the branches as a replacement for hops in Yorkshire, and Gale Beer is supposedly very thirst quenching. In addition to its intoxicating properties, it also attracts many insects which in turn attract greedy fish and its blue grey leaves give the fish more cover because they can hang around in deeper pools and not get snapped by equally avaricious heron. And who makes those deper pools?  - wait for it - beavers who tolerate salty water.

Apparently as salty as 10 parts per thousand (salt water is 35 parts per thousand). How salty is Alhambra creek? (We just spent the last hour looking up the salinity of Carquinez Strait, which now is reported in Practical Salinity Units PSU and not PPT…an exciting “sea” change that happened in the 1978 and is based on the conductivity of the salt rather than the weight, which is interesting but hardly the point. The internet can be very distracting.) Back to our story. So the testing for our section of bay ranges between 0-2 PPU depending on the time of year and depth of the water test, which means that we are sayyy under 10 PPT.

Which is why our beavers can go all the way down to the train tracks and grangers wharf and out to the straight and be okay. Dispersers can go down stream to crocket or Richmond and set up shop without difficulty. And which is why, if you love salmon and you want our schools to improve so that we can have a salmon season again next year. you had better make friends with some beavers.

Now whose going to break the good news to Scotland?

Heidi PerrymanI was at a not-beaver conference in LA this weekend and decided to take a closer look at this book on the airplane: The Beaver: Natural History of A Wetlands Engineer. It’s a rich and accessible read, and would easily make any willing participant a beaver expert in very short time. One of the parts that interested me the most was the information on youngsters leaving home to start out on their own.

The author, Dietland Müller-Schwarz, calls these kits “dispersers” and talked about their high-risk journey towards independence. They have to sleep under roots or in culverts on their way, and often meet the beaver of their dreams while their looking for a possible home. These beavers are also called “floaters” because they are essentially nomads searching for a residence. He noted that they are somewhat more likely to go downstream than up, (just because it’s less work than swimming against the current) but that “downstream-ers” tend to make a U-turn and come back up because conditions aren’t right more often than “upstream-ers” come back for the same reasons.

He said that dispersers can go any distance from 2-30 miles, but interestingly, it is the females that tend to disperse over the greatest distances, perhaps because they need a better food supply for their future breeding. It made me think that we should be taking a serious look at our creek, and identifying sites where a disperser is likely to settle, but also identify sites where we would *like* them to settle. Since no launch is expected before March 2009 we have time to make the potential sites more attractive, luring the kits where we want them, rather than dealing with any problems they might cause later.

At the Friends of Alhambra Creek Meeting the train tressel bridge was discussed as a possible good beaver site. Where else can you think of? As always you can email your thoughts to mtzbeavers@gmail.com.

My my my. We are getting more curious every day what kind of beaver developments are going on at the little tulle dam next to the footbridge. The purpose of the dam is obviously access to a deeper channel so the beavers can swim in safety to a remaining tulle stand in the corner near the amtrak parkinglot. They have clearly been digging trenches of mud so that the sometimes shallow water would cover them, and using the mud to build the dam-let. I’m happy to see that because when we lowered the dam by three feet I sometimes worried the water wouldn’t be deep enough for them to feel safe or get around. I always hoped they were digging passage ways to make the water deeper, and no one can complain about that.

This new channel is all about tulles and the dam-let protects it. Remember the little hole that dad dug through the birm into the scrape last summer? We never saw it used, but knew it was there for a reason. Now it leads to the dam-let and the channel and the beavers have expanded their territory by several square feet.

Which leaves the mystery of scenting to account for. Now scenting is essential beaver behavior, and the reason for those precious Castoreum glands that the horrible video yesterday showed perfume industries pirating. Scent marks can say “I am here” or “leave me alone” or “can I buy you a leaf?”. On several occasions a large beaver has been seen marking the dam-let as if he’s scenting. We wondered before if this were dad, but now we know it was a yearling engaging in the practice. Maybe he’s “practicing” for when he gets a place of his own. Or helping the family keep unwanted beavers away. Or just imitating what he saw Dad do. But I like to think of it as “pre-mating”. He’s telling the world who he is and what he has to offer, in the hopes of attracting some lucky beaver of his dreams. The imagined other would still need to take off with him in search of new territory, but its much easier to start out adult life with a partner.

Brave souls who can stand the cold might toddle down in the dark for a glimpse of the mystery in progress. Our friend at Allied Waste who wanted to donate blankets to the homeless as a thankyou for “keeping an eye on the beavers” just dropped off a lovely bundle yesterday and Cheryl helped them get distributed. Maybe they’ll share!

2008 Kit Cheryl Reynolds

Sometimes when you watch the beavers you observe them doing things that totally make sense; scooping up mud from a nearby bank to pat on the dam, chewing on a leafy twig, whining when their brother tries to take the twig they’re chewing. These behaviors are instantly recognizeable, we understand them right away and they soften our hearts with their familiarity.

But sometimes when you watch the beavers you observe them doing things that make no earthly sense to us whatsoever, like carrying mud from such a long way away it is a melted speck by the time it reaches the dam, or chewing the leaves off a blackberry branch and ignoring the luscious ripe fruit, or neglecting a big log and that seems just right for dam building. These are what I’ve decided to call Inscrutable Beaver Behaviors (IBB). Sometimes when you observe IBB you find out later it ultimately makes beavery sense in a grand Castor scheme that humans don’t understand at first. The beavers decision to ignore the repairs on the primary dam and tackle the secondary instead is an example of an IBB that turned out to be not just meaningful, but wise. Sometimes IBB occurs as part of a learning curve, and after a few stupid tries the kit gets it right–so it changes from an IBB to just a BB! The blind kit swimming in circles was an IBB that we eventually understood as because of his illness. Sometimes mysteries explain themselves.

But there are some IBB’s that will never make sense, and are just the wasted effort of an aquatic mammal that are fun to watch. This morning I saw an IBB in the form of a yearling carrying a mudball from what I used to call the “annex” pond all the way down to the primary dam. Swimming direction and circling can sometimes be an IBB. Yesterday Cheryl observed the kind of IBB that will probably eventually make sense, when she saw dad come out of the yearlings “frat house”. What examples of IBB have you observed?

Confusing and amusing as it can be at times, it is undeniably true that IBB is much easier to understand than its corresponding trait in humans: IHB.