Distribution
The bohemian waxwing is a northern bird, breeding in the taiga and muskeg of Alaska and northern Canada. In winter, it journeys southward to the Northern Rockies and Great Plains, and occasionally farther west and east in the lower 48 states. The cedar waxwing overlaps this range, sometimes traveling well north in lower Canada during the summer and occupying the bohemian waxwing's winter range year-round. But cedar waxwings also roam the southern U.S., northern Mexico and Central America, much further south than bohemians usually venture.
Size
Bohemian waxwings are heftier than cedar waxwings. An adult bohemian may have an inch or two over its smaller relative in total length and wingspan, and might weigh close to twice as much. Even when both birds are feeding alongside another, which is often the case in winter, this subtle distinction is of less use to the naked eye than other physical clues.
Appearance
Cedar waxwings appear slimmer and longer-tailed than bohemians. And while the cedar waxwing often appears to sport a large, heavy head in relation to its body, the bulky bohemian's is relatively smaller.
Plumage
The most noticeable differences between the two American waxwings lie in coloration and pattern. The bohemian waxwing is more gray overall; cedar waxwings have gray on their wings and tail, but show strong brown and yellow tones on their back and stomach. Cedar waxwings have a white undertail, while bohemian waxwings have a strongly rufous one; cedars have white on their forehead, while bohemians usually don't. The folded wings of a bohemian waxwing will show white or yellow blotches against their black borders, not seen in cedar waxwings.
Juveniles
Immature bohemian and cedar waxwings are both grayish with pale streaking. But a young bohemian already shows the red-brown belt on its undertail coverts, visible both on the perch and in flight; the juvenile cedar waxwing has the unremarkable white undertail of the adult.
Voice
Both waxwings have a relatively uncomplicated whistling call, high-pitched and sizzling. That of the bohemian waxwing tends to be raspier and lower in pitch, with a bit more body to the tone. The communal trills of a waxwing flock obviously announce its abrupt takeover of a fruit-laden elderberry or hawthorn.