 There have also been a few records in westernmost North America, mostly in western Alaska, but one on San Clemente Island off the southern California coast.At 13–14 cm long and 10–18 g weight, the red-flanked bluetail is similar in size and weight to the common redstart and slightly smaller (particularly with a slimmer build) than the European robin.As the name implies, both sexes have a blue tail and rump, and orange-red flanks; they also have a white throat and greyish-white underparts, and a small, thin black bill and slender black legs.