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:

Reference photo from Robert Harrington (An awesome bird photographer!):

Thursday, 5 January 2012


Hello everyone!

Sorry for the long break but I just went through a few very crazy months.  I'm changing PhD programs at the moment and that has basically required all of my attention.  I have, however, found some time to start drawing in a little Moleskine sketchbook I picked up at the beginning of this semester.  I decided that if I can't find the time to create full-size drawings anymore, I can at least do some small-scale, no pressure drawings in my sketchbook that I can share on here.

So, here are a few of the drawings I've done so far...

Nectarivores and bee balm.

The first sketch is of a few nectarivores (Ruby-throated hummingbird, Anna's hummingbird, Hemaris sp. hawkmoth, and an extraordinarily large honeybee) feeding from a bee balm (Monarda sp.) flower.  I decided to do this drawing for a few reasons.  First, I really need to improve my botanical illustration skills, so why not start with something that allows me to include subjects I'm already comfortable with, such as insects and birds?  Second, I've just never drawn a hummingbird before and was curious about the difficulty involved with drawing metallic feathers.  And finally, I've seen three of the four species pictured here feeding at bee balm in my home town and it's just one of those things that always seems beautiful and special, no matter how often you encounter it.
Spectacled flying foxes.

The second sketch is of five spectacled flying foxes (Pteropus conspicillatus).  Again, in an attempt to improve my botanical illustration skills, I chose a subject that would allow me to include both animals and plants into the composition.  I have had a special fondness for these bats ever since my trip to tropical North Queensland where I had the opportunity to witness hundreds of these massive bats leaving their roosts in the evening.  Whether creating a cacophony of chattering squawks from their roosts or taking to the wing in the hundreds, these megabats truly are one of the most spectacular animals in the world to observe in the wild.

Passalid beetles!

The last sketch I feel like sharing tonight is of a fascinating little insect called the passalid beetle.  It's also known as the bess beetle, betsy beetle, or patent leather beetle in North America.  I actually have a few colonies of these beetles in observatory cages in my house at the moment that I've been monitoring.  These beetles form monogamous pairs and males and females contribute equally to care of larvae.  Parental care on its own is pretty awesome, but these insects take it to the next level by incorporating cooperative brood care.  This means that adult offspring of the monogamous pair will remain in the natal nest (in this case, a rotting log) and help care for their younger siblings by building pupal cases and possibly feeding larvae.  As young adults, that is, post pupation and pre-dispersal, the exoskeletons of these beetles are not fully hardened.  This is why several of the beetles in the drawing are orange or red; the lighter color indicates a lack of pigment developed by the younger offspring.  I could go on for days about these beetles, but I will cut my summary short.  Take home message is that these beetles are beautiful live in cooperative family groups in rotting logs.

'till next time,