Black squirrels are a color morph of the Eastern Grey Squirrel (Sciurus carolinensis) which is widely distributed throughout the Eastern United States and Canada. The black variety is relatively rare, with localized populations becoming something of a tourist attraction. Southern Ontario and Michigan seem to have relatively large numbers of black squirrels. Legend says W.K. Kellogg brought black squirrels to the area. (Personally, I'm somewhat skeptical of this; black squirrels seem too broadly distributed in the area to have come from a single source.)
I teach economics at Kalamazoo College. My wife is also an economist. We were on sabbatical in Europe for the 2014-15 academic year. (Salamanca, Spain, followed by Oxford, UK.) We were in Uruguay for the 2006-7 academic year.