Thursday, February 26, 2015

Snowy American Crow

This cold and snowy American Crow huddled above the bird feeder on Wednesday morning. Look at the ice on its head, eyes, and back. Finally it dropped down and fed on scraps below the feeders. I have previously blogged on crows—you can search for these posts by using the search-box in the right column on this page. After you search once, remember to return to the whole blog before performing a second search.

A a few physiological adaptations allow crows to survive Minnesota winters. In warm weather, crows keep their body temperature near 40 degrees C (104 F).  In colder weather, crows are able to reduce their body temperatures as low as 38 degrees C (100.4 F). Obviously this plasticity saves energy. Their large size results in a relatively low surface to body mass ratio, also resulting in relatively lower heat loss (Verbeek and Caffery 2002). Finally, notice that, like many chilly birds, this crow has fluffed out its feathers, creating warm spaces near its body.

No comments:

Post a Comment