Sunday, January 29, 2012

Bohemian Waxwing

Bohemian Waxwings - Bombycilla garrulus

Waxwings fly in nifty cohesive flocks and they often turn abruptly in unison. The only other winter bird around my home that flies in cohesive flocks is the starling, which is smaller and stubbier, and nowhere near as pretty.



Waxwings eat fruit and the carotenoid pigments in their diet are responsible for the brilliant red and yellow colours at the tips of their feathers. The name "waxwing" is derived from the red waxy "droplets" that are on the ends of the secondary flight feathers of adults. Deposits of astaxanthin, a bright red carotenoid, are concentrated in the flat, expanded extensions of the rachis that project beyond the feather vanes. 
Yellow carotenoids, incorporated into the vanes at the tips of the tail feathers, are responsible for the trademark yellow tail band.
Waxwings drinking from Elbow River March 28, 2013
For about seven months from fall to spring, the waxwing diet is almost exclusively fruit. The birds arrive on the Mountain Ash, Dogwood, or Chokecherry in my backyard, and a large flock can consume all the fruit from an entire tree in one session. The birds pluck the whole fruit. The birds breed later in the season to coicide with the ripening of the local fruit. 
During the summer, the birds also eat insects, especially emerging aquatic insects. The perched birds in my photos above were doing just that. They demonstrated typical flycatcher eating behavior along the Elbow River. Since waxwings are related to flycatchers, this makes sense.    
The waxwings in the photos above and below were among dozens that congregated on ice along the Elbow River during a sunny warmer January day. The ice was melting and the birds were eating something red, likely berries, that had been frozen in the ice.


References

Sibley, David A. The Sibley Guide to Bird Life & Behavior. Alfred A Knopf, Inc. New York. 2001.

Tudge, Colin. The Bird. Crown Publishers. New York. 2008