Honestly, how do you handle squirrels that look almost the same? I tried sketching their tail patterns once, but they move so fast it's hard to be sure. Tbh, you might want to note their favorite trees instead, since they stick to areas. It still seems like a solid idea for keeping track.
Sketching tail patterns is a good try, but you're right about the speed. I had a similar issue with a group in my backyard. One squirrel always hid nuts under the same bush, so I named it based on that spot. Another had a habit of chasing blue jays away from the feeder. After a while, I could tell them apart by their daily routines more than their looks. Noting their favorite trees is definitely a smarter move.
Wait, they just cut down the TREE? Did they not even check if it was important to someone's system first? That's brutal. I'd be so mad if a crew came through and wrecked my whole way of telling them apart. What did you do after that, just start over from scratch?