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The cedar waxwing (Bombycilla cedrorum) is the most elegant of songbirds, sleek and silky and intricately styled. Its genus name, Bombycilla, derives from the Latin word bombyx for silk. The sexes look alike. Their buffy brown heads are adorned with a black face-mask outlined in white, a black throat, and a crest. Their bodies are tannish-yellow, transitioning underneath to soft yellow and then white on their backs, and to slate-grey on wings and tail. Their tails are tipped with yellow.
Adult secondary flight feathers are adorned with small, firm red tips that mimic red sealing-wax, hence the name “waxwing.” The red color results from the ingestion of a particular carotenoid pigment, astaxanthin. Wing tip function is unknown and may play a role in mate selection: the more tips, the older and fitter the bird, the greater the appeal to the opposite sex. The name “cedar” derives from their appetite for the berries of the red cedar tree.
Orange tail tips may appear on juveniles fed berries from the introduced Morrow honeysuckle before their adult molt to yellow, because the honeysuckle contains a different carotenoid, rhodoxanthin.
The common explanation for the species’ behavior stems from its preference for berries, which make up over 80 percent of its diet. Their peak breeding season is late, not until mid-June through August, when berries ripen. When berries are out of season, they eat insects, gleaning them from leaves and branches and “hawking” them over water. Apple blossoms and tree sap add to their diet in spring.
John J. Audubon wasn’t buying. Of the “cedar bird” he wrote, “Now reader, can you give a reason why these birds are so tardy in laying their eggs and rearing their young? It cannot be through want of fruit for the food of their progeny, as the young birds, being at first [for two days] fed on insects, might continue to be so, at a season when these abound, and as the old birds themselves evince pleasure at seizing them on the wing on all occasions.”
Cedar waxwings have a tolerance for simple sugars because they have the enzyme sucrase in their intestines, allowing them easily to digest sucrose and extract significant amounts of nutrition from berries. Many other berry-eating birds lack this enzyme. Cedar waxwings can live on a diet of fruit alone for up to two months, needing little protein.
Daubs of grape jelly attract them to feeders. They are inordinately fond of wild cherries. Other favorites include mulberries, strawberries and raspberries. Blueberry farmers are driven to despair when a horde of winter residents discovers their ripening crop of early blueberries and descends into the bushes by the hundreds. No conventional deterrent worked for a blueberry farmer in Hernando County, Fla. In frustration, she enticed a master falconer to fly his African Barbary falcon, Snyder, to frighten the birds. They simply flew to the neighboring farm.
The breeding ground of these gregarious North American birds spans the continent from east to west, primarily from southern Canada south into the U.S. midsection. Migration is wholly unpredictable. Some may migrate short distances when a cold front moves in or the supply of berries is depleted. Others may wander erratically as far south as Panama, in ever-expanding flocks in search of fruit. Cornell Birds of North America Online describes “a diurnal flight that occurred 5 Feb 1905 at Camden, SC, and took place throughout morning and afternoon: It involved an estimated 50,000 Cedar Waxwings and 25,000 American Robins.”
Many cedar waxwings winter in the north, where increased planting of berry-bearing ornamentals such as crabapple and hawthorn provide year-round food. They may become inebriated on fermented fruit and bang into windows, fly into traffic or simply drop to the ground. Sober waxwings have been observed snatching snowflakes.
At any time of year, they may appear suddenly, gorge themselves on berries, and move on; a flock of waxwings can strip a tree of berries in a matter of hours. Individuals may die of overeating.
Pairs probably stay faithful throughout the mating season. When a male chooses a prospective mate, he finds a delicious morsel. He perches, she perches, he does a little “Courtship Hop” and passes the food to her. She hops away, then back again and returns the food. Sometimes they touch bills, appearing to kiss. This exchange continues until one bird eats the offering and the nuptials are sealed. This morsel- sharing can also happen with multiple birds lined up on a limb, passing the food back and forth.
Both sexes select the nest spot, usually close to water, fruit trees and other waxwings. (They do not return to their prior breeding grounds.) Together, they construct the nest on a fairly low tree branch, using diverse materials including twigs, yarn grass, stems, rags and rootlets. While the female incubates the two to six eggs for about 14 days, she is fed by the male, who often perches on a nearby high branch as a sentinel. Nestlings remain in the nest about two weeks. About ten days after leaving, they are independent enough to join a flock of other juvenals. A second clutch is common.
A cedar waxwing does not “sing,” but repeatedly emits a series of high, thin trill and whistle calls modified for courtship or contact with the flock or to signify alarm. For this noisy trait, Catesby, a Scot who first described the wildlife of the Carolinas and the Bahamas, dubbed it “The Chatterer.”
Cedar waxwings have occasionally alighted in the trees at the southern tip of Northwestern’s lakefill, savoring insects.