Singing and defense of territories go hand in hand.
Cedar Waxwings do neither, so it's not too surprising that their main sounds, on display above,
don't have the complexity of most passerine songs (see link to Bobolink below for
extreme example) and that their vocalizing isn't as structured as singing (see link to
Bewick's Wren below). Instead, they are highly social year-round, and their calls are used
mainly for flock cohesion. The clean overslur is the seet and the zigzag one is the trill.
As you can see, they grade into each other. These sounds are very high and hard to hear, but I was close
enough to these birds to get a strong signal, so they are audible.
Of course, songs are often used for mate attraction, as well as for advertising territory. Waxwing haven't been
studied much, but they are known to have a courtship dance in which the pair passes a berry back and forth.
And birds with more red tips on their secondaries tend to pair with each other, nest earlier, and produce more
young. The red tips look like drops of wax, hence the name of the species and genus. Production of the red tips
appears to be a reliable badge of age, something that young birds can't manage. Given that waxwings travel in
flocks all winter, and thereby have plenty of opportunity for evaluating potential mates, they really don't have
much need for a long-distance cue to their fitness. Their plumage, though, is serenely beautiful.
By the way, take a look at the California Quail singing way under the waxwings at 0:20.
He's in the distance, and only the tops of his sonographic traces show. Click back to yesterday to see
what they look like when the bird is very close.