I've spent an equal time in Connecticut and New Hampshire over the past few months, and the red squirrels have been driving me crazy this season. Down in CT there are two of them who are constantly fighting over my friend's backyard. Some days they fight all throughout the daylight hours.
When they're one or two trees away from each other, they'll chirp every two seconds or so for at least 45 minutes at a time. If one wanders closer than that, they'll go into full chatter mode, which sounds like a teakettle at the brink of boiling. These little suckers are loud.
Both locations are too suburban to take the desired route, and down in CT even using a pellet rifle could result in a visit from the cops (too much risk of being spotted by passers-by). At this point I'm almost ready to go buy a slingshot and practice up.