The Bohemian Waxwing (Bombycilla garrulus) is a medium-sized songbird that breeds in the northern forests of North America, Europe, and Asia. It is highly migratory and nomadic, with large irruptions seen south of its breeding range in some years. The Bohemian Waxwing is considered a vagabond, wandering irregularly outside the breeding range in search of the fruit that makes up most of its diet. But what exactly is the range of this beautiful and gregarious bird?
Breeding Range
The Bohemian Waxwing breeds in the boreal forest regions of Alaska, Canada, and Eurasia. Its breeding range extends:
- In North America from central Alaska across northern Canada to Newfoundland.
- In Eurasia from Scandinavia across Russia to Kamchatka and the Commander Islands.
Within this broad breeding range, the Bohemian Waxwing nests in open coniferous forests, along forest edges, in parks, and in some urban areas with suitable trees. It requires trees for nesting sites but prefers more open habitat than dense forest.
Some key aspects of the Bohemian Waxwing’s breeding range include:
- Northern limit reaches about 70°N latitude.
- Southerly limit in western North America is about 60°N, and in eastern North America about 51°N.
- In Eurasia, southerly limit is about 60°N.
- Breeds at elevations up to about 1000 m in western North America.
- In Eurasia, found breeding up to 2000 m elevation in the Alps.
So in summary, the Bohemian Waxwing nests across the northern boreal regions of Alaska, Canada, Scandinavia, and Russia during the summer breeding season.
Nonbreeding Range
The nonbreeding range of the Bohemian Waxwing is much more extensive than its breeding range. This is because Bohemian Waxwings wander nomadically in search of fruit crops. Their movements are irregular and can be hard to predict, but some general patterns are seen:
- Irruptions occur periodically south of the breeding range, sometimes as far south as California, Texas, and Georgia in North America.
- Winters regularly throughout southern Canada and the northern U.S., south to Oregon, Minnesota, northern Pennsylvania, and Massachusetts.
- Also winters through Europe from Britain and Scandinavia south to the Mediterranean regions.
- Occurs as a winter visitor south to northern India and western China.
- Vagrant records exist from even farther afield, including Mexico, the Caribbean, North Africa, the Middle East, Korea, and Japan.
The Bohemian Waxwing’s winter range is driven by the availability of fruit crops. Some key fruiting trees utilized during winter include:
- Mountain Ash
- Crabapples
- Hawthorn
- Hackberry
- Persimmon
- Juniper
When these fruits are abundant farther south, Bohemian Waxwings are more likely to irrupt outside their normal winter range. They primarily occur in open habitats, including urban parks and gardens, during the nonbreeding season.
In summary, Bohemian Waxwings are found across much of northern and central North America in winter, and south to the Mediterranean region in Eurasia. Their nomadic wanderings make their nonbreeding distribution highly variable from year to year.
Elevational Range
The elevational range of the Bohemian Waxwing also varies by season:
- In the breeding season, found from sea level up to about 2000 m in mountainous areas.
- In winter, regularly occurs down to sea level and even below in some regions.
- Has been recorded up to 4000 m elevation when making high mountain passes during migration.
So while Bohemian Waxwings breed at middle elevations in northern mountain ranges, they can occur across a wide elevational gradient during the nonbreeding season and migration. This highlights their adaptability in utilizing food resources across different elevations and habitat types.
Total Global Range
Combining its breeding and nonbreeding distributions, the total global range of the Bohemian Waxwing includes:
- Alaska, Canada, and the northern U.S.
- Scandinavia across northern Europe to Britain and Ireland.
- Northern Russia across Siberia to Kamchatka and Commander Islands.
- In winter, southern Canada, northern and central U.S., south to California, Texas, and Georgia.
- In Eurasia, winters from Britain and Scandinavia south to the Mediterranean, northern India, and western China.
The total area occupied by the Bohemian Waxwing globally is estimated at more than 15 million square kilometers. However, the species is absent as a breeder or regular winterer from certain areas within this broad range, including Greenland and high Arctic regions.
Overall, the combination of its circumpolar breeding distribution and more southerly wintering range means the Bohemian Waxwing can be found across much of northern North America, Europe, and Asia during the year. But as a wandering, nomadic species, their distribution in any given year depends on highly variable conditions.
Factors Influencing Distribution
Several key factors influence the distribution of Bohemian Waxwings throughout the year:
- Breeding habitat – Require a mix of open conifer forest and forest edge habitat for nesting.
- Winter food availability – Irrupt south in search of fruit; northern limits dependent on food each year.
- Elevation – Use a wider elevational range outside breeding season.
- Climate – Mostly restrict breeding to subarctic and boreal climates.
- Irruptive behavior – Nomadic and unpredictable movements driven by food.
Understanding these influences helps explain the Bohemian Waxwing’s extensive range and irruptive winter movements. Their breeding habitat requirements and climatic tolerance restrict them as a nester, while their flexible diet and wandering nature expands their nonbreeding distribution.
Conclusion
In summary, the Bohemian Waxwing has a circumpolar breeding distribution across northern boreal forests, but wanders extensively outside the breeding season in search of fruiting trees. This leads to an expansive wintering range across much of northern and central North America and Eurasia, but with high irruptive variability. The total global range occupies over 15 million square kilometers, subject to annual and seasonal fluctuations depending on food resources. Factors like nesting habitat, food availability, elevation, climate, and irruptive behavior all help determine their range across the annual cycle. So while the Bohemian Waxwing depends on northern forests for breeding, it is perhaps better known as a wandering winter vagrant, tracing erratic paths across the northerly latitudes in search of its next fruit bonanza.
References:
- BirdLife International. 2020. Species factsheet: Bombycilla garrulus. Downloaded from http://www.birdlife.org
- Cornell Lab of Ornithology. Bohemian Waxwing Overview. https://www.birds.cornell.edu/home/
- Dunn, J. and Alderfer, J. 2011. National Geographic Field Guide to the Birds of North America. National Geographic Society, Washington DC.
- Newton, I. 2008. The Migration Ecology of Birds. Academic Press, London.
- Witmer, M.C., Mountjoy, D.J., and Elliot, L. 2014. Cedar Waxwing (Bombycilla cedrorum), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA. https://doi.org/10.2173/bna.cedwax.02