I usually see Fox Squirrels and Chipmunks around my house, but this summer this Red Squirrel (Tamiasciurus hudsonicus) has been resident in my backyard. He (or she) can steal a bird feeder full of sunflower seed in a single afternoon (somewhere nearby a few kilos of bird food is stashed away.) He "sings" for prolonged periods of time - up to an hour - sometimes chanting "chock-chock-chock" over and over from the top of the fence, sometimes sitting in trees improvising a mix of bird-like tweets with squirrelly scolding. He's not much larger than a chipmunk but unlike them he consistently outwits the resident cat.
A quick hand-held grab shot from this morning as the squirrel was serenading from the tree branches. Pentax K3, Tokina ATX 400mm f5.6.