You know in vampire movies how their eyes turn all black just before the bad guy reveals himself as a vampire....that's what I think whenever I look at a barred owl! It doesn't help that the only barred owl I ever worked with in captivity hated me like the righteous hate the devil. Apparently Steinbeck, the barred owl, considered me the devil himself! Only barred owl I ever saw in the wild was at the Tennessee Classic. She was a-hootin' away in the dark and I called back to her. We called back and forth for a bit before she came flying in to have a closer look at the weird barred owl with the bad northern accent!!!
In Minot, ND and Lacrosse, WI they have very high concentrations of black squirrels. Minot's population has 10-12% of the population showing the melanistic characteristic. Black squirrels also tend to be slightly heavier than the normal population. There is a general rule within populations that black, or melanistic, color phases are more common the further from the equator that the species is found. It gives them a slight advantage in cold climates to be able to collect a little added warmth from the sun!
Minot's population all descend from 12 pairs of normal colored squirrels brought in from some place in Wisconsin in the early 1900's. There are no native squirrels in that part of the country. Apparently several of those little tree rats carried the gene for melanism. With limited genetic stock, highly recessive genes like unusual coloration have a higher chance of expression.
Many people have noticed that black squirrels in Minot are significantly more aggressive towards people. They have been documented leaping onto people's backs as they walk under trees in Oak Park, running up people's legs, and even biting hands when offered peanuts. Now, before someone gets a racist thought in their heads, people tend to concentrate their efforts to feed squirrels on the black ones in the park because of their unusual coloration. ALL squirrels that receive concentrated attention from people feeding them will develop more and more aggressive tactics in order to extract higher rewards. For example, I once saw a black squirrel harass some kids until the kids threw the whole 2 lb bag of peanuts at the squirrel as they ran away. Animals (people included) tend to repeat behaviors that gain them a reward. Those kids jackpot-rewarded that nut thief for bad behavior!!!
I can just about hear that squirrel saying under his breath, "I gotta remember THAT trick. Oh yeah, baby!"