Saturday, May 27, 2017


Today Ken and I checked the boxes on the Reserve. We were particularly interested in Nest Box #15 (sort of like an address) where we discovered a nesting Western Screech Owl, 37 days ago in April. Today May 27, we saw a mom owl with her two owlets and a nice meal for the chicks, a deer mouse (peromyscus sp.)

A view from above: 3 screech owls and breakfast. Note the larger owlet on the left.
Owl eggs hatch asynchronously, so one will be a little older than the next.
Ken removed the female and lowered her down to me for banding. She remained still and calm through the process.We returned her to the box after taking some measurements and examining her condition.
Here I am taking the wing chord measurement of the owl.
Note the band on her right leg.

Then I looked at her brood patch. Hormones help release breast feathers providing direct heat exchange for incubating eggs and brooding young,until owlets can thermoregulate on their own. This female's brood patch is already getting pin feathers (two dark lines under her bare skin), because the owlet's feathers now keep them warm. By fall her breast will be feathered, which will help keep her warm for the winter months.

The brood patch, well past its use for warming chicks. Because the
chicks now have feathers they no longer need warming by the adult.
Leftover prey shows the male is a good provider. He was likely roosting in a cavity nearby, and maybe observing us. Stay tuned for the rest of the story!
A view with the mom removed. The owlets are about the size
of an adult deer mouse (right corner), and too small to band.
The Cornell Lab of ornithology is a great resource for bird natural history including screech owls. Also click here for a nice overview of owl courtship and reproductive behavior.