"Invasive" Squirrels

Range of American Red Squirrel (Tamiasciurus hudsonicus).
Range of Eastern Grey Squirrel (Sciurus carolinensis).

There are two native tree squirrel species in Minnesota. The Eastern Grey Squirrel (Sciurus carolnensis) would be familiar to almost anyone living in the eastern half of the USA, while the American Red Squirrel (Tamiasciurus hudsonicus) would be familiar to many people living in the north-east corner of the country (as well as most of Canada).

I happen to live in the native range of both species. I see them routinely in our yard... especially around the bird-feeder. The Greys climb down from above and snack directly from the feeder, while the Reds seem content with grabbing the seed spilled to the ground by avian visitors.

The Reds are about half the size of the Greys, but are much more feisty. We've watched single Reds aggressively attack single Greys, leading to the inevitable retreat of the larger Grey. The reds are generally more feisty, including in the intensity of their scolding calls when we scare them away from the porch.

The Greys make treetop nests out of leaves and branches. The Reds make homes of old woodpecker nests, burrows, or gaps in human establishments. We had to partially deconstruct a rear porch ceiling to discourage investigations by one Red, but most are content to reside in the piles of old wood just inside the edge of our woods.

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What got me thinking about squirrels was a discussion with my wife and a third party. The third party referred to the red squirrels as invasive. Both my wife and I responded that they actually were native to the area. Later I realized that the root of the disagreement likely came down to different definitions of the word "invasive". We were interpreting the word in the context of the red squirrels being native. The third party might have been thinking of the word in the context of the red squirrels invading human structures. I don't know that this was their meaning and I don't expect to bring up the subject again with them, but this realization helps reinforce the need to be clear on what are meant even by terms in common use. (I previously posted a more extended conversation about the meanings of "diversity" in biological contexts.)

If you find someone saying something that at first strikes you as absurd, it may be because they're using words differently than you are. Don't simply discount them as being incoherent. Try to determine what they mean, not just what they say. Once you've gotten through the barrier caused by sharing the same language, their experience may help expand yours.


References

• Tamiasciurus hudsonicus: en.wikipedia.org/wiki/American_red_squirrel
• Sciurus carolnensis: en.wikipedia.org/wiki/Eastern_gray_squirrel
• the-biologist-is-in.blogspot.ca/2015/03/biological-diversity.html