Birds known as eared-this or horned-that have neither ears nor horns.
(Actually, birds do have ears, but you can't see them.)
These birds get their names from erect headdress feathers — specialized feathers that rise from the head plumage.
There are great horned owls, long-eared owls, short-eared owls, horned larks, eared and horned grebes, and horned puffins. Minnesota has those species, save puffins.
If you look at these birds, naming seems to be arbitrary. We could have long-horned owls and short-horned owls. Or eared larks. Bird names often are arbitrary.
Of what use is a tuft of feathers on an owl's head? There is more than one answer, all of them suggested, one slightly firmer than the others.
First of all, how many owl species are there worldwide? And how many have those feather tufts, long or short? Just how often does this occur?
Number of species seems difficult to determine; I'm not certain why. I found one internet source declaring 248 species, another "about 200," a third "more than 225," a fourth specific at 132, and a fifth at 216, that number said by its author to be widely accepted. I doubt that.
The National Geographic Society, on its website, cites 225 species of owls in the world. Sounds good to me.
How many have feather tufts? The 248 source said about 43 percent. That is a number precisely vague, particularly since the number for species is questionable. If 43 percent is correct, using the NatGeo number would give us about 115 tufted owls worldwide. Give or take about one or two.
David Sibley tells us there are 19 owl species in North America. Sibley is a reliable source. His paintings show six species with horns or ears. Minnesota has four: those named above plus the Eastern screech-owl.
So what's their purpose? My source is a 1981 article by Michael Perrone Jr. in the Condor, a journal of the Cooper Ornithological Society.
Perrone says that the tufts create a profile that helps other owls with identification. The ears and horns create a distinct silhouette in poor light. An owl is asking, are you my kind of owl? Friend or foe?
A threatened owl with horns or ears will erect those feather tufts by contracting muscles, making itself look not only distinct but also tough. (A frightened owl might lay those feathers flat.)
Perrone says erect tufts make the owl's face resemble that of a mammal. That could discourage a predator, he writes in his paper.
Also, ear tufts could help the owl blend into its habitat. The tufts can resemble stubby or broken branches, according to Perrone, who adds that tufts are found more often on species that live in woodlands.
When threatened, owls can change their body shape, turning roundish into an upright slender posture. Ears and horns would enhance that.
Regarding concealment, the author says the theory is "generally believed." Other authors exploring this topic use the words "proposed," "possible," "reasonable" and the phrase "germ of an idea."
Science is not always precise.
Read Jim Williams' birding blog at startribune.com/wingnut.
