Branta Canadensis Meets Castor Canadensis

heidi08 Beavers elsewhere, New Species April 13, 2009

Our very own Cheryl Reynolds attended Saturday’s Pollinator Class at Mt. View Sanitation and was able to meet naturalist Jeff Alvarez, who will be helping us with our interpretive signs. He is very knowledgeable about and interested in beavers. They talked about the many ways beavers impact habitat, and the lodges being useful to all sorts of surprising species. Remember that lodges are lined with mud and highly insulated. During the day they are full of toasty cuddling beavers, and that makes the outside of the lodge warmer than the surrounding area. We saw this in person when we measured with the non-contact thermometer during the sheetpile installation. This is why lodges are so appealing to reptiles, why we used to see the pond turtles sleeping on the old lodge, and why the variety of snakes around and atop a lodge are greater than a similar area without a lodge.

It’s also why this Canadian goose, and many many others, decides to make her nest atop it. The eggs are warmed on both sides, and mom has an excellent vantage point.

For other photographs of geese nesting on lodges, go here.

Easter Beavers

heidi08 Earth Day April 12, 2009

Four family members this morning, Dad and Jr coming back under the Escobar bridge, and two kits swimming around the lodge. The water level is so nice it was like old times standing there and seeing them paddle around. Who noticed the pole besides me? Between the edge of the bridge rail and the beginning of the fence there has always been a child-sized gap. I have been mentioning it to city staff since the dam lowering in December 2007. Now there’s a lovely pole installed to block the fall through, which is nice and safe, though not the greatest for short people watching beavers…

We are hard at work on the beaver habitat diorama…Finished a cozy lodge and some beaver chews, and now am seriously thinking about putting some waders on a GI Joe…

It’s missing that something though, it needs that final touch. You had better come by on earth day and add it yourself. It won’t be right unless you help. Fro will be standing by with clay and advice to assist.

Full moon setting again behind the Alhambra hills around 6:30. Its a lovely sight, and I highly recommend it.

Blackberry time…

heidi08 Beavers elsewhere, Educational, Environmental April 11, 2009

One thing I discussed with Felix our tree-faring biologist was the seasonal nature of beaver diets. Ours seem to start enjoying blackberry bushes with the warmer months, and sure enough we saw two kits munching down on them this morning. One was doing the lovely reach under the trailing branches, and the other had hiked right onto the bank to munch at close range. Later he brought a stash of branches into the old lodge which seems to be functioning now like a picnic table. The dams look lovely, and the song sparrows and swallows are back in full force. It’s worth a morning walk if you’re so inclined.

Beaver friend Lisa Owens-Viani from the SFEP directed me to the March issue of the Chesapeake Bay Journal which has a host of articles on beavers.This delightful quiz is from educator and designer Kathleen Gaskell, and you should all do very well on it. The test construction-trained psychologist in me has a problem with number 2, and number 9 is actually a matter of some controversy, but its a fun challenge to your beaver brains.

1. When a beaver swims underwater, its heart beat drops to half of its usual rate and it uses up to 75 percent of the air in its lungs. (For a comparison, humans use 15 percent of the air in their lungs.) This allows the beaver to stay underwater for about how long?

A. 5 minutes
B. 10 minutes
C. 15 minutes
D. 20 minutes

2. True or false? When born, kits (baby beavers) are well-furred, have open eyes and are ready to enter the water within 24 hours. They are adept swimmers within two days.

3. True or false? On land, mother beavers have been observed carrying their kits with their forepaws and on their tails.

4. True or false? All beavers build dams.

5. Instead of months, Algonquin-speaking tribes’ gave each full moon its own name based on a natural event that usually took place at that time. Beaver Moon is the time of year when beavers are most likely to be seen because they are actively preparing for the cold months ahead. Which month does Beaver Moon refer to?

6. The average beaver today weighs 45-60 pounds and is 3-4 feet long. About 10,000 years ago, a giant beaver roamed North America. How big was it?

A. 150 pounds, 5 feet long
B. 300 pounds, 6 feet long
C. 400 pounds, 8 feet long
D. 500 pounds, 10 feet long

7. Beavers were once found in Great Britain. The word “beaver” is thought to come from an Old English word, “beofor.” What does beofor mean?

A. Brown animal
B. Moat builder
C. Paddle tail
D. Tree feller

8. True or False? In the winter, when ice makes it difficult to leave a frozen stream or river, beaver will eat fish living under the ice.

9. After man, which of these animals poses the greatest danger to beavers?

A. Bears
B. Foxes
C. Mink
D. Otters

Answers

1. C 2. False – Kits are adept swimmers at about one week. The rest of the statement is true. 3. False 4. November 5. A. 6. C 7. A 8. False, beavers are strict herbivores. In the winter, they feed on a host of logs and limbs that they have stuck into the stream or river bottom earlier in the year. 9. Otters. They are able to swim up the entrances of the beavers’ lodge, where they prey on the kits.

Kathleen A. Gaskell, the layout & design editor for the Bay Journal, has been involved with several environmental programs for children.

Beaver Flurry

heidi08 Beaver News, Educational April 10, 2009

Worth A Dam’s calendar is officially over booked. We are struggling to finish our amazing beaver habitat diorama for John Muir’s Birthday/Earthday next weekend. We were invited to attend the “Parking lot launch” for the Environmental Studies Academy students two weeks later, and we’re at the environmental fair for Wild Birds Unlimited the weekend after that. That takes us to Mother’s Day weekend and gives us two weeks off before the big train trip and beaver presentation May 27. Don’t ask about June.

In the middle of which I promised the John Muir Association I’d offer some guided beaver tours for the silent auction and have to design some certificates for them. I wanted to be dying eggs this weekend, instead I will be trying to make miniature cattails and tiny beaver chews. These pictures might be the closest I get to egg festivities, but they’re not bad. I assume you all got the identity theft warning email? If you didn’t go here: I don’t know what massive ad agency crew took these pictures but they are amazing and must represent hours and months of hard work. The email is titled “This Easter Beware of Identity Theft”.

Imagine the scope of this project: first you have to select the animals for matching and then get them to tolerate each other like old friends. I can only hope they weren’t medicated…and that the photographer was, because that must have been one stressful, animal stained photoshoot.

Anyone want to volunteer their dog or cat that looks like a beaver?

Great Dams! Shame About the Beavers….

heidi08 Environmental April 9, 2009

Matt Cawood, agricultural writer from Australia, began a series of articles on his blog for Stock and Land entitled “Beavers and the Murray.” In it he extols the book with which I hope by now you are all familiar: Eric Collier’s Three Against the Wilderness. Like others he was interested in the effectiveness of trapping small ponds of water through little dams and how it created a lusher, greener habitat that could withstand even dry periods. I was overly excited by the article, and suggested he might want to get in touch with our New Zealand friend who is talking about this very point with the local magistrate this month. He wrote back with a tone that could be politely described as gubenatorial,

I can’t imagine beavers themselves can or should play any role in Australia’s environment. It’s the principle of slowing water’s flow through the landscape that is interesting.

To paraphrase the Monks…Great Dams! Shame about the Beavers….

Okay so today is part II of his series in which he reveals that his secret to water holding isn’t beavers, its a series of low leaky weirs that hold the water back and an abundance of reeds that help them do so. The water is slowed and filtered, and the water table rises and in the hard rains the land is able to keep some of the aquatic wealth that otherwise pours uselessly out to the sea. He wonders what would the effect have been if such dams had been built on miles of wetlands 20 years ago?

Pointedly, he does not wonder if beavers have any role to play in Australia’s water problems. He also doesn’t wonder about any costs for building or maintaining these “leaky weirs” and whether it would be problematic for human hands to do so over miles of creek bed across the entire country. Another commenter wrote that beavers were reintroduced in South America and look at all the trouble they’ve caused. I guess that means that Australian farmers never prune their trees to make them grow back, because the failure to coppice is what makes the fate of South American trees different, not the lack of eager beaver predators.

Obviously his basic point is that beavers structurally may be onto something, but the beavers themselves are not welcome. Hmm. I wonder how Mr. Collier would feel about that takeaway from his novel?