Tuesday, May 19, 2009

Bison and birds

Photo by James Page, Parks Canada

We do not know all of the ways that the plains bison once helped maintain the health of our grasslands on the northern Great Plains, but it seems fair to guess that its role was central and went well beyond the direct effects of grazing. How did their wallows, pockmarking the plains as divots of mud and dust, play into the long term patterns of plant succession and micro-cummunity? Was there anything about their droppings that the prairie has missed since they've been absent?

With more bison on native rangeland than at any other time in the past 120 years, there are now some opportunities to look at these and other questions. The new herd in the West Block of Grasslands National Park is thriving, according to a recent report in
the Globe & Mail
, and it seems that already grassland birds are taking advantage of the new conditions the bison have created. For example, some songbirds, the report suggests, are already using bison fur to line their nests. Its great insulation value may help egg and nestling survival, which is always an issue for ground-nesting birds, particularly in springs such as this one with late snow storms and prolonged periods of sub-zero temperatures. Meanwhile, sharp-tailed grouse are said to be using grazed down patches of prairie to hold their spring leks. This summer, students will be researching the effects of bison on songbirds in the park.

All very encouraging as evidence that birds and plains ecology in general will benefit from the return of bison. The task ahead of us in coming years is to find ways to work with landowners, stakeholders, consumers and producers to bring an economically workable and ecologically-sustainible vision of large-scale bison range into the light of day.

Hills in the West Block of Grasslands National Park

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