5/31 -- Squirrels

Mammals, as I learned recently, have a huge diversity. Today we narrowed the scope down to a local level, learning about mammals around campus. First, we learned about how many scientists, including a graduate student at UW, trap mammals for study. This method is mainly used for squirrels, but would suffice for mammals of a similar size. A trap is baited with walnuts, and once the squirrel enters, the door is shut. The researcher then must come back within two hours to ensure that the squirrel is not harmed by predators. They can then get any information they need or attach tracking devices for population sizing.
One problem we learned of was the fact that Eastern Grey squirrels are dominating over the native Western Grey Squirrel. This is due to the fact they are often bigger and better at foraging, eating almost whatever they can find. They do scatterhoarding, which is where the squirrel will fill a shallow hole with food and cover it up. They have great spatial memory, allowing them to remember hundreds of these stashes. Eastern Greys leave scent markings by chewing off parts of bark, which causes glands to release pheromones. This could possibly be used for pest control in the future, as some bugs will shy away form the pheromones. Other than these squirrels and raccoons, it is hard to find any other mammals on campus. Some other Washington squirrels include the yellow-bellied marmot. This is a much larger squirrel and hibernates, lives in rocks, and is an omnivore. Unlike many squirrels, one male yellow-bellied marmot can have up to three females. In Eastern Washington, one can find the Colombian brown squirrel. These weigh between one and two pounds and live in colonies.

I was left wondering how the spread of the Eastern Grey squirrels will affect both the Western Grey population and also the ecosystem that it is native to. It didn't seem as if the Eastern Grey was all that different, so will it do much harm to the local ecosystem? Perhaps the fact that it is much better at foraging will result in other species losing potential food source. The damage to the Western Greys is already seen, with the squirrel only being found in certain forests through out the state. Will their numbers continue to dwindle, or will they atleast be able to retain the habitat they have now?

Posted on June 5, 2012 05:33 AM by beardendb