AboutRoger Lederer Expertise Any and all about wild birds - the science of ornithology. Information about birdwatching, ecology, conservation, migration, behavior, banding, rehabilitation, feeding, songs, binoculars, identification, and careers in ornithology. No questions about pet or caged birds, please.
Experience Have a PhD and thirty five years as a professional ornithologist - research, teaching, author, speaker, webmaster of Ornithology.com . Have written thirty scientific papers, two bird field guides, a textbook in ecology and two recent books entitled "Amazing Birds" and "Birds of New England". Have traveled to over 80 countries watching birds.
Expert: Roger Lederer Date: 6/5/2008 Subject: Owl's Hearing
Question QUESTION: I observed that an owl's skull has what I suppose are 4 ear openings toward the front of the face. Two larger openings at approximately 2 and 8 o'clock and two smaller ones at 10 and 4 o'clock. Since with 2 ears we are able to place a sound on the surface of a cone, if the owl essentially has 2 sets of ears, each set having a different pitch (frequency), then it seems reasonable that he should be able to locate a sound as being at the intersection of 2 cones at different angles making the location of the sound almost exact. Does this sound reasonable to you?
ANSWER: I'm not exactly sure what you are looking at, but the owl has only one set of ears. The openings you are looking at may be for arteries or veins, nerves, or muscles. Simply, owls' external ears are similar to ours but they are shaped differently from each other (ours are the same shape) and one is located slightly higher than the other. This difference in shape and location helps to locate a sound. So your idea is correct, but not because they have two sets of ears.
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QUESTION: Thanks for the thoughtful reply. I tried to find the particular skull picture (perhaps a boreal owl?) that instigated all of this but to no avail. I wouldn't think such relatively large circular openings in the face would be for blood flow or muscles. I don't think of owls contorting their faces. I may have leapt to the wrong conclusion about the hearing but if the openings do collect sound and channel it to the "real" ears...ok, maybe not...or it may be a research grant waiting to happen. Thanks again for your time and attention.
Answer Well, I'm not sure about the large openings you refer to then. The sound is collected by the fleshy part of the ears - part of the skin which you won't see on the skull when the skin is removed. The actual opening to the inner ear which leads to the ear mechanism and auditory nerve is small - about 2 or 3 times the diameter of a toothpick.The only large opening is for the eyes.
