Q: I’m a big owl fan and have seen several kinds, especially the great horned owl. But I wonder: Why I don’t ever see short-eared owls?
A: These tawny owls with their dramatically outlined eyes spend their time in wide open spaces in their daily hunt for small rodents. You almost surely won’t see them in a city setting but you might try visiting wide grasslands, such as at Carlos Avery Wildlife Management Area (north of Forest Lake) in the late afternoon to try to spot one or more of these owls. Three Rivers Park District has suitable habitat, as well. These owls are more likely to be found in summer or fall, since most head southward for the winter. Short-ears can be spotted in the daytime, and often share the same habitat as hawks called Northern harriers. Amateur photographer Darlene Herbster recently caught a tense interaction between a Northern harrier and a short-eared owl: Watching an owl drop to the ground, the hawk assumed it had caught a vole, so it flew down to try to steal it (a practice called kleptoparasitism). The two raptors faced off for a bit, then the owl flew off, its empty talons revealing that it had missed its prey. So both birds left the field without a meal that time.
Cold toes
Q: Why don’t birds’ feet freeze?
A: The birds we see in our backyard do get cold feet: According to the Cornell Lab of Ornithology there is so little fluid in the cells of their feet, and their feet are mostly tendons and bones with little muscle or nerve tissue, that they don’t get frostbite. Their circulation is so fast that blood doesn’t stay in their feet for very long; instead they have an exchange system where blood flowing back to the body is warmed by blood flowing to the feet. Birds may also stand on one foot at a time, tucking the other into their downy feathers to warm up. When perching, they can lower their bodies to cover their feet to warm them with their feathers.
‘Frozen’ birds
Q: A little woodpecker was perched on my suet feeder for many minutes, not moving a muscle. What was up with that?
A: Danger was around and some other bird’s signal or a shadow told your woodpecker, probably a downy, that a hawk, cat or other predator was around and looking for a meal. Woodpeckers aren’t fast flyers, and if a hawk is hunting in the area, a downy caught at a feeder can’t count on making it to safety in a tree or shrub. Its best defense is to freeze in place, hoping to escape notice.
Beak color
Q: I’ve noticed that starlings in winter have dark-colored beaks, instead of the yellow color in summer. I understand how birds’ plumage can change color after a molt, but how can a beak change?
A: That’s an excellent observation, and a number of birds, including goldfinches, robins and starlings, change their beak color from season to season. These birds’ diets include foods that are rich in the pigments that give color to beaks (and feathers). When mating season approaches, hormonal changes lead to color changes in the tissue beneath the outer layer of the beak. A bright yellow or orange beak seems to signal how robust and healthy a bird is, leading to better chances for a better mate. After the breeding season, when the birds no longer need to send such signals to each other, the bright color fades. Cardinal beaks change color, too, but not on a seasonal schedule: Cardinal youngsters have dark beaks until they’re about 6 months old, then their diet leads to permanent bright orange beaks like their parents’.
