Waxwings and Silky Flycatchers (Bombycillidae)

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Waxwings and silky flycatchers

(Bombycillidae)

Class Aves

Order Passeriformes

Suborder Passeri (Oscines)

Family Bombycillidae

Thumbnail description
Sleek, medium-sized, berry-eating songbirds, with plump bodies, short bills and crested heads

Size
5.9–9.4 in (15–24 cm); 1–2.1 oz (30–60 g)

Number of genera, species
5 genera; 8 species

Habitat
Forest, open woodland, semi-arid scrubland, and desert

Conservation status
Most species widespread and common, none are targeted for conservation efforts

Distribution
North and Central Americas, north temperate Eurasia, Middle East, and Indian subcontinent

Evolution and systematics

Despite the ubiquity of some members of the Bombycillidae, the taxonomic status of the waxwings, their relationship to the gray and silky flycatchers, and indeed the relationships among these flycatchers themselves, remains controversial. Most modern taxonomic treatments place the waxwings proper (Bombycillinae) within the order Passeriformes together with the silky flycatchers (Ptilogonatinae) and the palmchat (Dulidae). This classification is based primarily on coloration, nesting, skeletal features, musculature, and results of DNA-DNA hybridization studies. Here the consistency ends. Waxwings have also been allied with several other Passeriformes, including thrushes (Turdidae), Old World flycatchers (Muscicapidae), pipits (Motacillidae), and starlings (Sturnidae). More controversial is the placement of the gray hypocolius (Hypocolius ampelinus). This Middle Eastern bird is frequently allied with the other bombycillids, either as a sub-family or as a monotypic family closely related to the waxwings and silky flycatchers. However, Hypocolius has also been allied with the bulbuls (Pycnonotidae) and thrushes. Further research is needed to resolve these relationships.

This treatment recognizes three subfamilies. They are the waxwings: Bombycillinae, comprised of one genus and three species: the cedar waxwing (Bombycilla cedrorum), bohemian waxwing (B. garrulus), and Japanese waxwing (B. japonica). The silky flycatchers, subfamily Ptilogonatinae, with three genera and four species: the phainopepla (Phainopepla nitens), black and yellow silky flycatcher (Phainoptila melanoxantha), long-tailed silky flycatcher (Ptilogonys caudatus), and gray silky flycatcher (Ptilogonys cinereus). The latter is not to be confused with the only member of the third subfamily—the gray hypocolius (Hypocolius ampelinus) of the Hypocolinae.

Physical characteristics

Bombycillids are medium-sized songbirds with short bills, sleek plumage, head crests, and tails of varying length. The waxwings have fawn-gray bodies, and black chin and eye masks. Their wings have contrasting plumage with white, crimson, or yellow patches and their common name refers to the red, wax-like tips present on the secondary flight feathers. (These are absent however in the Japanese waxwing.) All have a bright band of orange or yellow at the base of the tail. The cedar waxwing's tail band is usually yellow, but in the past 30 years many have been sighted with orange tail bands, apparently due to pigments in the fruits of the invasive European honeysuckle (Lonicera spp.), which has successfully established itself in the United States and is eaten by the birds.

Silky flycatchers have longer tails than waxwings and their head crests (present in three of the four species) often appear as erect bristles. The plumage is black, gray, or brown, some species have brightly colored patches of yellow or white. The gray hypocolius is gray with a black tail band and face mask.

Distribution

The ranges of the three subfamilies are quite different. Waxwings, whose fossils have been reported from the Pleistocene in California, are distributed across the temperate Old and New Worlds; the cedar waxwing winters as far south as Guatemala. Silky flycatchers occur from the southern United States into Central America. The gray hypocolius is found in the Middle East and on the Indian subcontinent.

Habitat

The habitat preferences of the bombycillids vary, although all occur where they can find fruits and berries. Waxwings prefer open woodlands and hedgerows, and increasingly are found in suburban areas. Silky flycatchers and Hypocolius inhabit desert and arid scrub-land.

Behavior

All bombycillids are gregarious, social birds, although to varying degrees. Silky flycatchers nest in loose colonies and are somewhat territorial. Waxwings are non-territorial, and will form flocks of thousands, migrating erratically to areas of high fruit density. Bent (1950) wrote of the Bohemian waxwing "We never know when or where we may see these roving bands of gypsies. They come and they go, we know not whence or whither, in the never-ending search for a bounteous food supply on which to gorge themselves." Bombycillids are migratory, the phainopeplas moving altitudinally to moister habitats after breeding. They are quite vocal birds, their calls a mixture of chatters, warbles, and whistles.

Feeding ecology and diet

Bombycillids feed predominantly on small fruits, which are the mainstay of the diet for the north temperate species for seven months of the year. They also eat insects, plucking them off of vegetation and tree bark or swooping down from high perches and taking them in flight. The cedar waxwing can store ingested fruits in a portion of the esophagus, presumably to maximize the amount of food ingested while foraging. Unlike fruit-eating thrushes, they have the enzymes to digest sucrose. In recent years, waxwings have come to rely increasingly on crops and ornamental fruits planted in suburban areas. While it will eat a variety of fruits, the phainopepla specializes on mistletoe (Phoradendron spp.) berries and is closely associated with these plants that grow on the trunks and branches of mesquite.

Reproductive biology

Waxwings are socially monogamous and the same is believed of silky flycatchers, though their habits are less well known.

The breeding season of waxwings is one of the latest of North American birds, with eggs laid from early June through August. Adults tend to pair with similar-aged birds, and pairs of older birds nest earlier and raise more young than younger birds. Copulation in waxwings is preceded by courtship-hopping, which often involves passing a small item such as an insect or flower petal between male and female, and touching the bills together which results in a clicking noise. All bombycillids make a small, cup-shaped nest, usually at a strong fork in a tree. The female does most nest building in the waxwings, while the reverse is true for the phainopepla. Clutch sizes range from four to six in waxwings, from two to four in silky flycatchers. In both groups the young hatch naked and blind and are fed crushed berries and insects by both parents. The breeding biology of the gray hypocolius is not well known.

Conservation status

No conservation measures have been taken for the family, and none appear needed. According to Breeding Bird Survey data, cedar waxwing populations have increased across North America, and phainopepla populations remain stable. The status of populations of Middle Eastern and Central American species is not well known, but as of 2001, none are listed as Endangered or Threatened.

Significance to humans

The irregular mass invasion of Europe and temperate North America by waxwings has caused them to be considered pests at times. As they have become more prominent in suburban areas, more cedar waxwings are killed by flying into windows.

Species accounts

List of Species

Cedar waxwing
Bohemian waxwing
Phainopepla
Gray silky flycatcher
Gray hypocolius

Cedar waxwing

Bombycilla cedrorum

subfamily

Bombycillinae

taxonomy

Bombycilla cedrorum Vieillot, 1808. Two subspecies (B. c. cedrorum and B. c. larifuga) are recognized by some researchers based on geographic variation in plumage.

other common names

French: Jaseur des cèdres; German: Zederseidenschwanz; Spanish: Ampelis Americano.

physical characteristics

6.1 in (15.5 cm), 1.1 oz (32 g). Smaller of two North American waxwings. Sleek, crested birds with small bill, overall plumage grayish brown with pale yellow belly. Adults have black face mask with white edge and black chin patch. Named for red, wax-like tips on the secondary flight feathers of many adults. Pointed wings, tail square with distinctive yellow band at tip. Female chin patch may be smaller and lighter colored. Red wax-tips absent and plumage more gray than brown in juveniles.

distribution

North to southeast Alaska, throughout Canadian provinces, east to Newfoundland, throughout United States and Central America to Panama, east to Bermuda, occasionally winters in West Indies and the Bahama Islands.

habitat

Uses various open woodland forests and old fields; avoids forest interior; also found in riparian areas of grasslands, farms, orchards, conifer plantations, and suburban gardens.

behavior

Very social species, flocking throughout year. Rarely ventures to ground, frequent preening at high exposed sites. Nonterritorial, but may show aggressive behavior near nest. Short flights are direct with steady wing beats. Two basic calls; rapidly repeated buzzy or trilled high-pitch notes and high-pitched hissy whistles.

feeding ecology and diet

Diet consists mainly of fleshy fruits, but also includes insects caught in air or gleaned from vegetation. Forages in branches of fruiting trees, typically plucks fruit while grasping a branch. Fleshy, berry-like cones of cedar (Juniperus spp.) historically dominated winter diet. In spring, this bird will hang from maple (Acer spp.) branches to feed on suspended drops of sap. Instances have been recorded of cedar waxwings becoming drunk from alcohol in overripe fruits. This often results in them falling to the ground, hitting windows, being hit by vehicles, and dying from injuries.

reproductive biology

Appears to be monogamous within a breeding season. Among latest-nesting birds in North America, apparently cued to midsummer ripening of fruit. Lays two to six sparsely spotted pale blue-gray eggs, in woven cup-like nest. Female incubates, 12–15 days. One to two broods per season. Young hatch naked and blind; both parents feed nestlings. Fledge 14–17 days. Occasional brood parasitism by brown-headed cowbirds (Molothrus ater).

conservation status

Not threatened. No conservation measures have been taken for cedar waxwings and none appear needed. Sharp population increases occurred in late 1970s, in apparent rebound from elimination of DDT in agriculture and increase in edge habitats conducive to fruit-bearing shrubs.

significance to humans

Commonly killed by hitting windows, perhaps because many ornamental fruit-bearing shrubs are planted near homes.

Bohemian waxwing

Bombycilla garrulus

subfamily

Bombycillinae

taxonomy

Bombycilla garrulus Linnaeus, 1758.

other common names

English: Waxwing; French: Jaseur boréal; German: Seidenschwanz; Spanish: Ampelis Europeo.

physical characteristics

6.7–8.3 in (17–21 cm), wingspan: 14.5 in (37 cm), 2 oz (56 g). Larger and slightly shorter-tailed than the cedar waxwing, appears small-headed and round-bodied. Sleek, crested bird, overall plumage grayish with rusty tinge on forehead and cheeks. Black eye-mask and chin patch, white edge between eye-patch and chin, little to no white on forehead. Undertail rust colored. Yellow band on terminal end of tail, yellow and white bands on wing. Characteristic red wax droplets on some secondaries of many adults. Juvenile resembles adult, but lacks wax droplets and rust coloring on head.

distribution

Holarctic, northern Eurasia, to northeast and north-central China, northwest and north-central North America.

habitat

Old stands of coniferous trees, with open canopy and rich field layer.

behavior

Very social species, flocking throughout year. Characteristic silvery buzzing sirr of flock call. Nomadic and irruptive; occasionally large flocks invade Europe and the United States, presumably due to fruit shortages in northern regions. Non-territorial, but may show aggressive behavior near nest.

feeding ecology and diet

Diet mainly sugary, fleshy fruits, especially rose-hips (Rosa spp.) and mountain-ash berries (Sorbus spp.); also insects in spring and summer. Birds may gorge themselves until they can hardly fly.

reproductive biology

Monogamous. Late breeder, from early June through August. Lays four to six pale bluish gray eggs spotted with black in woven cup-like nest. Female incubates, 12–15 days. Young hatch naked and blind; both parents feed nestlings; fledging 14–17 days.

conservation status

Not threatened. Widespread but can be intermittent, numbers of breeding pairs may vary considerably from year to year.

significance to humans

Has been considered a pest in some areas during irregular mass-invasions in Europe.

Phainopepla

Phainopepla nitens

subfamily

Ptilogonatinae

taxonomy

Phainopepla nitens Swainson, 1838. This species is often considered a distinct family.

other common names

French: Phénopèple luisant; German: Trauerseidenschnäpper; Spanish: Papamoscas Sedoso.

physical characteristics

6.3–9.4 in (16–24 cm) Sleek, long-tailed, crested birds with rounded wings. Adult male has a short black bill and ragged crest, glossy black with white patches on wings (white not visible when perching). Female is ashy-gray with whitish edges on all wing feathers. Juvenile resembles female, gradually acquires black feathers throughout first year.

distribution

Americas only. North to central California, south to Panama.

habitat

Arid scrub-land and open woodland within reach of water courses. Believed to breed in lowland deserts and then move to higher, moister habitats.

behavior

Somewhat social, nests in loose colonies and forms small flocks in non-breeding season. Territory size varies with food abundance. Call a soft-rising whistle hoi; song a mellow, gurgled warble, series of short phrases with long pauses between krrtiiilwa. Also mimics other species.

feeding ecology and diet

Diet mainly fruit and berries, some insects often caught on the wing. Phainopepla is closely associated with mistletoe, a parasitic plant that grows on many desert trees especially mesquite (Prosopis spp.). Phainopeplas have a specialized digestive system for consuming mistletoe berries. In the gizzard they remove the seed and pulp from the seed coat of the berries; they then digest the pulp and defecate the seeds and seed coat separately, usually on the branch of the tree where the bird was perched. The seeds sprout in the tree, continuing their parasitic lifestyle, having been dispersed by the bird.

reproductive biology

Monogamous, with large breeding territories. Breeding pairs form loose colonies where food sources are concentrated. In a courtship display a male flies as high as 300 ft (90 m) over his territory, chasing the female while making circles and erratic zig-zag patterns. Two to three grayish blue, mottled eggs laid in cup-shaped nest of plant matter, spider webs, and hair; nest built in central fork of a tree. Both parents incubate 14–16 days; young hatch naked and helpless. Fledge at 18–25 days. Phainopeplas can product two to three broods per year.

conservation status

Not threatened. Breeding Bird Survey data suggest population levels have been stable since the 1960s, however, reliance on mesquite and mistletoe makes the phainopepla vulnerable to habitat loss.

significance to humans

None known.

Gray silky flycatcher

Ptilogonys cinereus

subfamily

Ptilogonatinae

taxonomy

Ptilogonys cinereus Swainson, 1827.

other common names

English: Gray silky; French: Ptilogon cendré German: Grauseidenschnäpper; Spanish: Capulinero Gris.

physical characteristics

7.3–8.3 in (18.5–21 cm). Sleek, long-tailed birds with crests and small bills. Male's head, crest, and upperparts blue-gray, with white eye crescents and black wings. Belly white, black tail has bright yellow undertail with a white band. Female head and crest grayish, upperparts, throat, and underparts dusky wine-colored with yellow undertail. Whitish belly. Juvenile resembles female, but belly dull yellow.

distribution

Middle Americas. Throughout Mexico, south into Guatemala at 3,300–11,500 ft (1,000–3,500 m), lower in winter. Documented twice in Texas, sight records for southern Arizona. Also seen in southern California, though may be an escape.

habitat

Humid to semi-arid pine-oak and evergreen forest, wanders to adjacent habitats in winter.

behavior

Commonly seen in pairs or small flocks; often perches conspicuously atop tall trees; flies high. Call is chattering and nasal: chi-che-rup, che-chep and k-lik, k-li-lik. Song a pleasant, soft, warbled series of clucks with intermittent quiet whistles.

feeding ecology and diet

Diet mainly insects, often caught in flight, and fruits and berries.

reproductive biology

Monogamous. Lays two bluish white eggs, speckled and spotted with brown and gray, in cup-like nest of fine plant material and lichen; nests in bushes or trees. Female incubates for 12–14 days, young hatch naked and blind. Nestlings are fed by both parents and fledge in 18–20 days.

conservation status

Not threatened.

significance to humans

None known.

Gray hypocolius

Hypocolius ampelinus

subfamily

Hypocoliinae

taxonomy

Hypocolius ampelinus Bonaparte, 1850. Single species in subfamily, taxonomy contoversial. Allied with thrushes, Turdidae (Lowe, 1947); throughout latter half of 1900s usually considered a subfamily within the waxwings. Sibley and Monroe (1990) and Clements (1991) suggest it might be closely related to bulbuls (Pycnonotidae), although affinities uncertain.

other common names

English: Gray flycatcher; French: Hypocolius gris; German: Seidenwürger; Spanish: Hipocolino Gris.

physical characteristics

Crested, long-tailed birds with white on primaries. Male has black mask that encircles the head and black band on tail, in flight shows black primaries with prominent white tips. Female sandy-brown with creamy throat, lacks black mask, tail tip dark. Juvenile resembles female.

distribution

Breeding range centered in Iran and Iraq, east to Pakistan, winters in Saudi Arabia. Rare and irregular visitor to India.

habitat

Semi-desert with scattered thorn scrub of berried bushes or around oases and date palm plantations.

behavior

Gregarious, in winter seen in flocks up to 20 birds. Flight is strong and direct with rapid wing beats and occasional swooping glides. Raises ear coverts and nape-feathers when excited. Call a mellow, liquid tre-tur-tur, and whee-oo.

feeding ecology and diet

Feeds mainly on berries, occasionally insects. Chiefly forages in trees and bushes, hopping about, occasionally descends to the ground to pick up insects.

reproductive biology

Lays three to six pale bluish gray eggs with black or brown speckles which may merge around the broader end of the egg to form a distinct ring.

conservation status

Status uncertain, but not currently a target of conservation efforts.

significance to humans

None known.

Resources

Books

Grimmett, Richard, et al. Birds of the Indian Subcontinent. London: Christopher Helm Ltd., 1998.

Helle, Pekka, and Timo Pakkala. "Waxwing." In The EBCC Atlas of European Breeding Birds, edited by Ward J. M. Hagemeijer and Michael J. Blair. London: T. & A. D. Poyser, 1997.

Sibley, Charles G., and Burt L. Monroe. Distribution and Taxonomy of Birds of the World. New Haven: Yale University Press, 1991.