Bowen Island in BC would like to know where all these darned beavers come from? Obviously, they say, they weren’t here before the nineties so who brought in all these beavers?

Inquiring minds need to know. This article by Alan Whitehead of the nature club demands answers.

How long have beavers been on Bowen Island?

There were no beavers on Bowen Island / Nex̱wlélex̱m when my young family and I moved here in the early spring of 1988. Beavers first appeared, if memory serves me, in the early 1990s in the Lagoon and soon moved upstream all the way to Killarney Lake. Long-time residents told me there had been muskrats, which had been trapped out in the first half of the 20th century, but told no similar stories of beaver. Fast-forward a few decades and beavers, their dams, lodges and cut vegetation can be found in many places, especially though not exclusively in the Killarney-Terminal watershed.

There were no beavers when we got here. And the old timers who were here since the 1900’s say there were none in their lifetimes, so where how did they get here? Never mind that the fur trade wiped most of them off the face of the earth in the 1830’s and they’ve been slowly clawing their way back into existence since then. In fact Bowen Island might even have been the upper edges of the ‘fur desert’ HBC helped create to keep the nasty foreigners from settling in.

Bowen Island is a metro of Vancouver and located about 1.9 miles off the shore. Gee how long does it take a beaver to swim 1.9 miles?

The beavers’ arrival in the 1990s was on the east side of Bowen via Deep Bay. It is, therefore, very likely that they must have come from the Fraser valley lowlands, where beaver populations have been increasing over the past century as a result of the decline in trapping, construction of drainage canals, and other changing land uses. Beavers are strong swimmers. Although they live in fresh and brackish water, they are known to cross significant spans of saltwater; this happens particularly when the young adults are dispersing away from their birth habitat after their second year. Beavers have no trouble navigating the waters between the mouth of the Fraser River and Bowen Island and beyond.

A beaver has to find his own space in the world, don’t you know. You can’t just stay in your parents front yard forever.

Are the beavers now here to stay? Yes, but only in the best habitats. Judging from the large girth of some of the cedars that have been gnawed as a source of bark for food, I suspect that life is not easy for the young beavers that, during their dispersal, try out the more remote locations. In these areas, the preferred forage plants are scarce, and streams and wetlands tend to go dry during the late summer and early fall, leaving beaver dams temporarily useless. In the prime habitats, however, such as Crippen Regional Park, the new municipal park at Grafton Lake, and possibly other existing and future protected areas, beavers will likely endure thanks to the continuing abundance of year-round food and shelter habitat and a connection to Howe Sound for dispersal and recruitment of mates to maintain genetic diversity.

Gee I don’t know. You don’t have any willow on that island? Any aspen or dogwood or birch? I’m sure skunk cabbage and ferns will do in a pinch. Obviously there’s something to eat or there wouldn’t be beavers eating it.