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Thursday, November 6, 2014

"the sleeping one"

Coming back from field work just after sunset, I was surprised to hear Eric say, "There's a poorwill."  I had to ask again to make sure I heard him correctly.  Sure enough, there was a Common Poorwill (Phalaenoptilus nuttallii) sitting on the trail ahead of us.

I didn't have the right lens on the camera, so I had to make a change as quickly as possible.  And it was very dark, except for the full moon and our headlamps.  I took two pictures before the poorwill flew off.  They're not the best, but since they're my first pictures of this species, and this is one of my favorite families of birds, I decided to go ahead and show them.

Common Poorwills are members of the nightjar family which also includes nighthawks and whip-poor-wills.  They're known for their cryptic plumage, and being crepuscular (active near dawn/dusk) or nocturnal (active at night).

Poorwills are one of the smallest nightjars, at only 19-21 cm (7.5-8 inches) long.  They have very large eyes with a tapetum lucidum, a layer that reflects light back to the retina and helps with vision in low light conditions (it's the reason for the glow in these images).

According to the Birds of North America account, the Hopi Indians called Common Poorwills, "Hölchoko" or "the sleeping one."  They were aware of its ability to enter torpora state of physical inactivity usually marked by reduced body temperature and metabolic rate.  Poorwills will enter torpor in response to low temperatures or lack of food.  When in a state of torpor, body temperatures as low as 5°C (41°F) have been recorded and oxygen consumption rates may be reduced by over 90%!  

In Sonoma County, Common Poorwills are uncommon during the summer and rare during the winter, so consider yourself lucky if you see one!

1 comment:

Amy Heath said...

Thank you for this blog post. After just learning about this bird and wondering what the Hopi word for The Sleeping One is, I was delighted to find it here. I was composing an acrostic poem on hibernation. I entitled it "Hölchocko". Thank you.