The Bohemian Waxwing ( Bombycilla garrulus) is a passerine bird known for its nomadic behavior and preference for fruit. These birds roam across the northern United States and Canada, and even into Eurasia, in search of sustenance, particularly during the non-breeding season. Their name, "Bohemian," reflects their unconventional and seemingly carefree lifestyle.
Identification
Measuring approximately 7 1/2 - 8 1/2" (19-22 cm), the Bohemian Waxwing is similar in appearance to the Cedar Waxwing, with a crest and yellow tail tip. However, it is larger and grayer, with chestnut undertail coverts and a distinctive yellow and white pattern in its wings. Juvenile Bohemian Waxwings can be distinguished from young Cedar Waxwings by the color of their undertail coverts.
Adult Bohemian waxwings have soft, dense feathers that are kept in good condition by preening. All adult waxwings have a complete molt annually between August and January. Juveniles molt at the same time but retain their flight and some other wing feathers. The male of the nominate subspecies has a black mask through the eye and a black throat. There is a white streak behind the bill and a white curve below the eye. The lower belly is a rich chestnut color and there are cinnamon-colored areas around the mask. The rump is grey and the tail ends in a bright yellow band with a broad black border above it. The flight feathers are black and the primaries have markings that produce a yellow stripe and white "fishhooks" on the closed wing. The adult's secondaries end in long red appendages with a sealing wax appearance. The eyes are dark brown, the bill is mainly black, and the legs are dark grey or black. The female Bohemian waxwing is very similar to the male but has a narrower yellow terminal band to the tail, a less defined lower edge to the black throat, and slightly less distinctive wing markings. Juveniles are duller than adults, with whiter underparts, only a few red wing tips, no black on the throat, and a smaller black face mask. Compared to the nominate subspecies, eastern B. g. centralasiae is paler, greyer, and has little reddish-brown behind the bill. The American subspecies B. g.
Their call is a high-pitched, lisping seeee, harsher and more grating than that of the Cedar Waxwing.
Habitat and Distribution
Bohemian Waxwings have a circumpolar distribution, breeding in northern regions of Eurasia and North America. During summer in Alaska and western Canada, scattered Bohemian Waxwings may be seen perching on spruce tops.
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They breed in far northern forests in open areas, around edges of burns or bogs, or in places with scattered taller trees above brushy understory. They prefer open evergreen and mixed forests, frequently near lakes, ponds, or streams in northern North America and Eurasia.
In winter, these birds become sociable nomads, with large flocks wandering the northwest in search of berries. In winter these same birds become sociable nomads, with large flocks wandering the northwest in search of berries. Sometimes they stray as far east as New England, but in most areas their numbers are quite variable from year to year. Similarly irregular south of Canada in the west. Movements are highly variable. In some winters, big flights extend as far east and south as New England, while in other years they are almost absent there.
During the nonbreeding season they roam through open woodlands, urban areas, roadsides, and parks, stopping wherever they find fruit. They often concentrate in towns, where plantings of fruiting trees provide abundant berries. In some cities in the prairie provinces of Canada, Bohemians can be found by the thousands every winter, no doubt lured by the plantings of mountain-ash and other fruiting trees. Outside the breeding season, waxwings will occupy a wide range of habitats as long as suitable fruits are available. They may be found by roads, in parks and gardens, or along hedges or woodland edges. Eurasian birds normally winter from eastern Britain through northern parts of western and central Europe, Ukraine, Kazakhstan, and northern China to Japan. North American breeders have a more southeasterly trend; many birds winter in southeast Canada and smaller numbers in the north-central and northeastern US states.
Diet and Foraging Behavior
Bohemian Waxwings are opportunistic feeders, with their diet varying depending on the season. Mainly insects and berries. They are herbivores (frugivores) and carnivores (insectivores).
During the summer, they feed mostly on insects, especially flying insects, which they catch by watching from a high perch and then flying out to catch them in mid-air. They also forage in trees.
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As berries and fruits become available, they make up most of their winter diet. Important food sources include berries of mountain-ash and junipers, as well as strawberry, mulberry, serviceberry, raspberry, cranberry, hawthorn, Russian olive, and apple. They also eat seeds of birch and other trees and will drink oozing sap. The Bohemian Waxwing eats insects and some fruit during the breeding season, but switches to eating almost entirely fruit during the nonbreeding season. The higher sugar content of dried fruit means that waxwings frequently drink water and even eat snow to help with digestion. They take berries while perched or hovering. Except when nesting, they almost always forage in flocks.
Bohemian waxwings can eat huge numbers of berries; each bird sometimes consumes several hundred a day, more than double its weight. Fruit is rich in sugar but deficient in other nutrients, so Bohemian waxwings must eat it in large quantities. These birds have a large liver which helps to convert sugar to energy. They can metabolize alcohol produced from the fermentation of those sugary fruits more efficiently than humans, but may still become intoxicated, sometimes fatally. Bohemian waxwings often drink water or eat snow in winter, since the sugar in their fruit diet tends to dehydrate the birds.
Social Behavior and Breeding
Bohemian waxwings are social birds. They forage in large flocks, sometimes of several hundred birds, and in winter roost communally in dense trees or hedges, sometimes with American robins, fieldfares, or other wintering species.
Bohemian Waxwings don't defend breeding territories and don't often return to the same areas to breed, unlike many songbirds. This lack of territoriality is most likely the result of the ephemeral and clumped nature of the fruit they rely on. Perhaps because they don't defend territories, they also don't have a true song-songs that other birds use to defend territory. Bohemian Waxwings form monogamous pairs for the duration of the breeding season, but pairs frequently form during winter.
Courtship displays may include both birds perching close together with body feathers puffed out. Courtship displays may include both birds perching close together with body feathers puffed out; male passes berry, flower, or other item to female. Males court females by fluffing up body feathers, raising the crest, and pushing the tail downward. After grabbing a female's attention, the male passes food to the female and she passes it back to him. They continue to pass the food back and forth up to 14 times before mating. Older males have more red tips to the wings and are usually preferred by females.
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They start their return from the wintering grounds in February or March, but northern breeders do not reach their breeding areas until April or early May. Breeding occurs from mid-June to July. Bohemian waxwings are not highly territorial, and, although normally they nest solitary, several pairs may nest close together where there are several good nest sites.
The nest is placed on a horizontal branch of a tree, often spruce, usually 6-20' above the ground, sometimes much higher. Bohemian Waxwings nest along forest edges and openings near lakes, streams, and marshy areas. The nest is frequently on a horizontal branch of an evergreen, aspen, or alder tree. Nest (built by both sexes) is an open cup of twigs, grass, and moss, lined with soft materials such as fine grass and feathers. Male and female Bohemian Waxwings gather evergreen twigs, grasses, mosses, and other plant fibers, but only the female builds the nest. She weaves the material together to from a cup nest that is approximately 6 inches across and 3 inches deep.
The eggs are pale bluish gray, heavily dotted with black, especially toward the larger end. The clutch is 4-6 eggs, sometimes fewer. The eggs are a glossy pale blue spotted with black and grey and the clutch is 3-7 eggs. Incubation is probably by female only, about 14-15 days. The eggs are incubated for 13-14 days by the female alone. She is fed regurgitated berries by her mate and rarely leaves the nest. Both parents feed nestlings. The chicks are altricial and naked, and have bright red mouths; they are fed by both parents, although the male brings most of the food, mainly insects, in the first few days. The young are subsequently fed largely with fruit. Young leave the nest about 14-18 days after hatching, continue to associate with parents for some time thereafter, perhaps remaining with them through first fall and winter migration.
Conservation Status
Bohemian Waxwings are common, and Partners in Flight estimates their global breeding population at 5 million, but populations in North America declined by 55% since 1970. Partners in Flight rates the species 10 out of 20 on the Continental Concern Score, and included Bohemian Waxwing on the list of Common Birds in Steep Decline. These species are too numerous or widely distributed to warrant Watch-List status but are experiencing troubling long-term declines.
According to the IUCN Red List, the global Bohemian waxwing population size is 14,400,000-28,150,000 mature individuals. The European population consists of 1,080,000-2,110,000 pairs, which equates to 2,160,000-4,220,000 mature individuals.
Bohemian Waxwings are susceptible to window and car collisions because fruiting shrubs are often near buildings and roadways.
Ecological Role
Bohemian waxwings are important seed dispersers in their ecosystem. In some years, Bohemian waxwings erupt south of their normal wintering areas, sometimes in huge numbers in search of the fruit that makes up most of their diet. The birds will stay until the food runs out and move on again. In what may be the largest ever irruption in Europe, in the winter of 2004-2005, more than half a million waxwings were recorded in Germany alone.
Additional Behaviors
During the nesting period, male Bohemian waxwings may sometimes deter rivals from approaching their mates, and females may squabble over nest sites.
When alarmed, Bohemian waxwings "freeze" with their bill and neck pointing upwards. If this fails, they fly, calling noisily. The common call of these birds is a high trill 'sirrrr'. Other calls are just variants of the main vocalization; a quieter version is used by chicks to call parents, and courtship calls, also given during nest construction, have a particularly large frequency range.