? Early emergence of fledgling owls, Yolo

Rick Williams

There have been reports from Oregon and British Columbia of raptor centers receiving many fledgling hawks and owls abandoning nests because of the extreme heat.  My backyard barn owl nest box is shaded and on extreme heat days I put up a mister that keeps the temperature about 10 degrees cooler than the ambient air.  This has prevented crowding at the entrance hole.  Last evening the first fledgling emerged after dark.  In 6 years of observation, this fledgling had the most down I have seen, though the first fledgling usually emerges from 6/15 to 7/15, so it is not that early.  I have read that fully  developed plumage helps insulate the bird, and so a downy bird may have more susceptibility to heat stress.  Barn Owls have a body temperature of 104 degrees F (40 C).  Hopefully it will survive.  There seemed to be 2 or 3 more fledglings by sound earlier, but I have not heard them of late, so this may be the only survivor.

Rick Williams, Woodland, CA