Wildlife – Worth A Dam

Yet Another Marin Sewage Spill

bruce85@mac.com Uncategorized February 24, 2008

Gary Bogue has details of yet another sewage spill into the bay from Marin. The relevant public officials in Marin County have some explaining to do…

Beaver Sunday

bruce85@mac.com Beavers February 24, 2008

This morning’s visit to to pond showed the rain had raised the water level and slightly damaged the park side of the secondary dam, but was just flowing nicely over the top of the main dam. A quick glimpse of a beaver swish in the water, and everything looked right with the world. There are rumors of a giant beaver costume going to make its appearance on main street, I’ll keep you posted when I know more details, but I’m hoping the appearance will make it into the documentary! Made me think of a massive pied-piper type parade where droves of chanting school children follow the giant beaver and maybe the high school marching band plays the Beavers fight song. (Clearly the campaign has gone on too long…)

On a more studious note, beaver-loyalist Linda tracked down this brief article from the Audubon Magazine issue July-August 2007. Apparently a young male beaver made an unexpected appearance at the Bronx Zoo’s millpond. The article, by Ted O’Callahan states:

“The beaver is nicknamed Jose after US representative Jose Serrano who secured 15 million in federal funding for restoration of the formerly garbage-clogged waterway…Here is nature doing what we couldn’t even imagine, says Eric Sanderson, an ecologist with the wildlife conservation society that overseas the Bronx zoo. The rebounding Bronx river is now home to 45 species of fish and serves as a migratory corridor for birds.”

Catch that? Mo’ better fish with beavers, which is what Igor Skaredoff reported at last Tuesdays meeting after attending the beaver conference in Oregon. It has been shown that the standing crop of “plankton” in beaver ponds is 5 times larger than in the unaltered flowing stream. This means that fish life is denser and more varied…which means that the things that eat the fish life are denser and more varied too. Nice find, Linda. Let’s all get our bird books and start the count of what our beavers have added to the corridor. Here’s the picture that ran with the article…

Dispersers

bruce85@mac.com Beaver Behavior, Educational May 28, 2010

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.