A quick history (links below): I think we first saw them in 2008; at least, those are my first photos of beaver-felled trees. At the time, they were colonizing the newly-landscaped lagoons in Cougar Creek park, and had dammed the outlet of the creek. The next year, they had dammed the inlet, as well, creating a small pool on the upper level. The city has fenced and wired the trees, sometimes reinforcing them with wired-on chunks of wood. They've removed the dams, they've caught and killed a male, they've cleared trees off the banks, which just exposed the banks to erosion, but didn't deter the beavers.
By last November, the family had succeeded in damming the upper creek, filling in what had been a wasteland with a slow, muddy trickle down the centre. It made a pretty duck pond, striped with reflections from the alders around it, over patterns of green and gold animated by swimming, dabbling ducks.
|Map of ponds last November. The newest addition is to the right of the blue area.|
This January, the dams and the new pond were gone. We went back in March, and the three dams were back; the upper pond was filling again. Mallards, wigeons and mergansers were busy in the new feeding ground; as usual, a heron was hunting along the edges.
I took my grandson down to the park to show him the beaver dams in September. We were disappointed; not only had people removed all the dams, they had gone into the wasteland with machinery and scraped off all the vegetation, leaving no small wood for beavers to start up with again. (So much for the much-advertised "Releafing Project".) All that was left was bare, oozing mud. A lonely pair of ducks patrolled the lower lagoon; nothing else, not even the heron.
We went back yesterday. Now there are three good dams, and a lodge. The upper pond covers the machine scar nicely, and they've built another dam at the top, making a new, third pond. The ducks are back.
|The upper pond, with the re-routed creek coming in at upper right.|
|The upper lip of the second dam traps fallen leaves.|
|On the far side of the new duck pond, the latest dam raises the creek to a third level.|
|The latest tree felled. It has been stripped of small branches for food and construction materials. About a meter along the trunk, the beavers have cut half-way through, to make a sturdy support beam for one of their projects.|
|Mallards peacefully grooming in the middle pond.|
|Mallards and reflections.|
Persistence pays; it's been a long, slow struggle, but the beavers are advancing. Two steps forward, it is, and one step back. But those steps forward add up.
I've blogged their ongoing story here: March, 2007; May, 2009; November 2011; January, 2012; March, 2012.