The cedar waxwing (Bombycilla cedrorum) is a member of the family Bombycillidae or waxwing family of passerine birds. It is a medium-sized bird that is mainly brown, gray, and yellow. Some of the wing feathers have red tips which resemble sealing wax, giving these birds their common name. It is a native of North and Central America, breeding in open wooded areas in southern Canada and wintering in the southern half of the United States, Central America, and the far northwest of South America. Its diet includes cedar cones, fruit, holly berries, and insects. The cedar waxwing is listed as least concern on the IUCN Red List.
Bombycilla is Vieillot's attempt at Latin for "silktail", translating the German name Seidenschwänze. Vieillot thought that motacilla, Latin for wagtails, was derived from mota for "move" and cilla, which he thought meant "tail"; however, Motacilla actually combines motacis, a mover, with the diminutive suffix -illa. He then combined this "cilla" with the Latin bombyx, meaning silk. The specific epithet cedrorum is Latin for "of the cedars".
Description
thumb|left|Audubon's illustration
Cedar waxwings are medium-sized birds approximately long and weighing roughly . Wingspan ranges from . They are smaller and browner than their close relative, the Bohemian waxwing (which breeds farther to the north and west). Their markings are a "silky, shiny collection of brown, gray, and lemon-yellow, accented with a subdued crest, rakish black mask, and brilliant-red wax droplets on the wing feathers." These droplets may be the same colour as the madrone berries they are known to eat. These birds' most prominent feature is this small cluster of red wax-like droplets on tips of secondary flight feathers on the wings, a feature they share with the Bohemian waxwing (but not the Japanese waxwing). These wax-like droplets are attributed to the pigmented and medullary layers of the secondary tip being surrounded by a transparent cuticle. The wings are "broad and pointed, like a starling's." The tail is somewhat short and square-tipped. Its call can also be described as "high, thin, whistles." with erratic winter movements, though most of the population migrates farther south into the United States and beyond, sometimes reaching as far as northern South America. They will move in huge numbers if berry supplies are low. Rare vagrants have reached western Europe, and there are two recorded occurrences of cedar waxwing sightings in Great Britain. Individual Bohemian waxwings will occasionally join large winter flocks of cedar waxwings.
Behavior and ecology
Cedar waxwings are sociable, seen in flocks year round. The male will do a "hopping dance" for the female. If she is interested, she'll hop back. especially because it feeds in large groups.
When the end of a twig holds a supply of berries that only one bird at a time can reach, members of a flock may line up along the twig and pass berries beak to beak down the line so that each bird gets a chance to eat.
Sometimes, cedar waxwings will eat fruit that is overripe and has begun to ferment, intoxicating the bird. Reliance on primarily fruit alone occurs until fruit cessation in the spring when the birds start to feed on insects and flowers. In such cases, intestinal analysis revealed stomach contents of 84% fruit, 12% invertebrates, and 4% flowers, among 212 individuals involved in the study.
Despite the advantage of frugivorous specialization, they did lose body mass when experimentally fed one fruit type alone (Viburnum opulus), but gained body mass when fed pollen-rich catkins as well (Populus deltoides). Many fleshy fruits are energy-rich. However, they are deficient in the nitrogen (protein) levels required by cedar waxwings (1.7%). The nutrient deficit of sugary fruits alone is mitigated through flower and subsequent pollen consumption that is rich in protein. This response to food diversity illustrates the importance of multiple food sources in order to acquire the precise nutrients needed to maintain bodily metabolism.
Even though waxwings displayed efficient rates of digestion, they also exhibited relatively quick passage rates that are indicative of their low utilization efficiency (36.5%), as fruit skins appeared undigested in feces. The low utilization efficiency of fruits digested by cedar waxwings not only indicates the necessity of consuming large quantities of fruits, but viable seeds found in feces also suggest the important role they may play in seed dispersal. A positive correlation between seed defecation and fruit consumption is seen as rates of ingestion increased only when rates of seed processing also increased.