Sunday, 4 March 2012

Cedar Waxwing

Hello Folks!


I'm shifting focus away from arthropods today and introducing one of my favorite bird species, the cedar waxwing (Bobycilla cedrorum).  I tend to see these birds hanging around streams and lakes feeding on various red berries.  The bird in my drawing is feeding from a dense species of serviceberry (Amelanchier sp.).  Although I've been fortunate to spot watch these birds through binoculars on multiple occasions, I actually didn't know much about cedar waxwing biology before attempting this drawing.  I will share with you a few interesting facts I found on the Cornell Lab of Ornithology webpage about these beautiful birds.  
Drawn with prismacolor colored pencils on colored matte board.


The first bit of information I found interesting about these birds is that they are apparently one of the only North American birds that eat fruit year round.  Like all adaptations, their specialized diet comes with costs and benefits.  Because berries aren't very nutritious, the birds need to eat a fairly large quantity of fruit to extract the nutrients they need.  Sometimes this need to intake large amounts of berries can lead to foraging errors in which birds can potentially poison themselves by feeding on berries that have fermented on the branch.  On the other hand, this specialized diet can also protect them from brood parasitism.  As many of you may know, Brown-headed cowbirds are brood parasites that lay their eggs in other birds' nests, forcing their hosts to take care of their offspring.  Often the hosts can lose their entire brood to starvation when there is a cowbird in the nest.  Because the cedar waxwing diet consists almost entirely of berries, cowbird chicks deposited into their nests often starve to death.  While I haven't found any data on this, I assume that because cowbird chicks often do not survive in cedar waxwing nests, the cedar waxwing's chicks are more likely to survive a cowbird parasitism event.  





Detail of cedar waxwing.

Life history information taken from:
http://www.allaboutbirds.org/guide/Cedar_Waxwing/lifehistory/ac

Reference photo from Robert Harrington (An awesome bird photographer!):
http://robert-harrington.com/


No comments:

Post a Comment

Post a Comment