Jays, chickadees, titmice, nuthatches, juncos, cardinals – these are the staple birds of winter, familiar to nearly all feeder watchers in the Northeast. In some years, nomadic finches such as siskins, redpolls, and grosbeaks add spice to our feeder lineup. But for sheer visual elegance, unpredictability of occurrence, and nonconformity of habits, waxwings have no rivals among winter birds. Human-provided feeders hold little interest for them; as consummate frugivores, waxwings seek fruit-laden trees and shrubs, often descending in hordes that can number hundreds, gorging while supplies last, then moving on. Views of these plump, sleekly crested, crisply plumaged birds can be stunningly close-up and prolonged, or tantalizingly distant and fleeting.
Of three species in the worldwide avian family Bombycillidae, two – the cedar and Bohemian waxwing – grace our northern landscapes in winter. The more common and reliably occurring cedar waxwing nests in our region and may overwinter here, while bohemians are irregular, itinerant winter-only visitors from breeding grounds far to the northwest, between central Alaska and Manitoba. Both species’ winter patterns of movement and occurrence are dictated by fruit supplies, which vary unpredictably in space and time. Some winters feature throngs of either or both waxwings – often in mixed flocks – festooning trees such as crabapples, mountain ash, and cherries. In other winters, both Bohemians and cedars may be absent or scarce.
Although technically classified as songbirds, neither cedar nor Bohemian waxwing vocalizations approach what any human would consider a classic avian “song.” Both species’ thin, high-pitched, lisping calls often signal their presence, either in flight or perched high in bare treetops, just before they descend upon a grove of fruit-bearing trees. Waxwings’ lack of true songs probably reflects their nonterritorial social structure, and ultimately their year-round frugivorous diet. Both species specialize on sugary fruits, which can be locally but sporadically superabundant, are ephemeral, and therefore cannot be readily defended as a resource. This in turn promotes a gregarious lifestyle, discourages territoriality, leads to nomadic movements, and results in delayed breeding schedules. Cedar waxwings are among the latest-nesting birds in North America, often initiating nests in July or early August.
As for many irruptive migrants (including boreal finches), whose seasonal movements vary widely from year to year and are driven by food supply, the migrations of Bohemian and cedar waxwings qualify as facultative, or partial. Put simply, individual birds or entire populations may move in one winter, sometimes over vast distances. Alaska-breeding Bohemians, for example, may disperse to New England, while East Coast cedars occasionally range as far south as Costa Rica or Panama. In a subsequent winter, the same waxwings that previously wandered thousands of miles may stay put, as long as food supplies are adequate to sustain them. Alternatively, they may remain on or close to breeding areas as long as fruit persists, then move after depleting their local food source. Even at a given wintering site, once a favored grove of fruit trees has been stripped to emptiness, the marauders have no choice but to move.
Both waxwing species play a key ecological role as year-round seed dispersers of native and introduced fruiting plants, a consequence of their voracious feeding on fruits and high degree of mobility. Even in summer, Bohemian and cedar waxwings effectively disperse seeds of early-fruiting shrubs such as common serviceberry and various cherry species. One study suggested that cedar waxwings may disperse serviceberry seeds 50 miles or more! On the flip side, non-native invasives including honeysuckle, autumn or Russian olive, bittersweet, and buckthorn are readily spread by the wanderings of waxwings.
For winter-weary birders and natural history enthusiasts, the spectacle of voracious waxwing mobs descending on groves of crabapple or mountain ash, often by the hundreds, exceptionally by the thousands together, stirs our souls. The slightly larger and splashier Bohemian, with its rich, rusty undertail and streaked white wings, is a prize by any measure. Etched against a stark blue winter sky and snow-covered branches, these spiffy, gregarious, and often highly approachable avian vagabonds lift us from our midwinter doldrums.