Wednesday, December 12, 2012

WAXWINGS, THE SMOOTHEST BIRDS


Anyone who looks closely at a waxwing usually exclaims "how smooth it is!" What is there about waxwing feathers that gives this impression? They really do seem smooth, perhaps in part because the body is uniformly colored and the individual feathers thus difficult to make out. Maybe that's all we need to know. Their jaunty crests, black face masks, and yellow tail tips make waxwings unmistakable birds.

Cedar Waxwings (Bombycilla cedrorum) are very common in the Pacific Northwest. Small numbers of them spend the winter, especially in the interior, but many more arrive in spring to breed throughout our deciduous and mixed woodlands. Because they are confirmed fruit-eaters, they breed later than many other migrants, so the young when just off the nest can find plenty of fruit. Many native trees and shrubs flower in early summer and have mature fruit in late summer, if you didn't know.

Waxwings are really tied to fruit and can survive on a fruit-only diet longer than other temperate zone songbirds. Males offer berries to females for courtship feeding, and the young are fed fruit more than is the case in most of our birds. Of course this diet is augmented with insects, which are better sources of some nutrients. Waxwings spend much time around water looking for emerging aquatic insects such as dragonflies, which they often catch in the air.

You can see waxwings hawking for insects above the treetops in late summer, but they are still seeking fruit at that time, and any plant fruiting in September may harbor small flocks of waxwings. In October, most of them take off for lower latitudes.

The "waxy" tips on wing feathers in waxwings are merely modifications of the feathers. Imagine the individual feather barbs becoming thicker and thicker, fusing, and becoming bright red. As a waxwing matures, it develops more of these tips, and their size and number are a sign of maturity. Birds with more red tips tend to breed together and breed more successfully, so more "wax" may be a sign of a bird with higher fitness.

Bohemian Waxwings (Bombycilla garrulus), bigger and more colorful, visit the Northwest only in winter from their breeding grounds in the boreal forest. They are more common on the east side of the Cascades, where flocks may be encountered in fruiting trees, many of them non-natives and often in cities and towns.

There is only one additional waxwing, the Japanese species (Bombycilla japonica). It looks much like the other two but has red tail tips; I wish I had a photo to share, but I've never seen one.

Dennis Paulson

3 comments:

Quinci said...

What an interesting-looking bird! Does the type of fruit it eats affect the color of its feathers?

Anonymous said...

They really do look smooth. Is there any benefit to the species for the dark masks around their eyes?

Dennis Paulson said...

Quinci, fruit does affect the color of their tail tip. It becomes oranger when they have a diet of some kinds of fruits containing high concentrations of carotenoid pigments.

Anonymous, we don't know of any benefits conferred by the dark masks, but it may be just to identify them (to others of their species) as waxwings. Dark colors around the eyes may also reduce sun reflections from those feathers, improving their vision on bright, sunny days.