Feb 07 2012
Do owls hoot more when the moon is full?
Eurasian eagle owls do. Maybe great horned owls do too.
In 2009 biologists conducted a study in Spain to find out if moonlight influenced Eurasian eagle owl vocalizations. They radio-tagged 26 breeding eagle owls and tracked them continuously during all phases of the moon.
When the scientists analyzed the data they found that the amount of hooting was directly correlated to the amount of moonlight. On new moon nights the owls hardly hooted, but as the moon got brighter they had more to say and they said it from higher perches where their white throat patches gleamed in the moonlight as they spoke.
The white throat patch is important.
Like our great horned owls (Bubo virginianus), Eurasian eagle owls (Bubo bubo) have white throat feathers that are only visible when they hoot. (The owl in this picture is hooting even though we can’t hear him.) In bright moonlight the white throat patch is apparently a visual cue that backs up the sound. Perhaps it helps the mate or rival find the bird that’s vocalizing.
Tonight the moon is full. Will our great horned owls be talking? Listen…
(photo by Adam Kumiszcza from Wikimedia Commons. Click on the photo to see the original)