Jays
A Blue Jay taking off with an acorn
Flashing white in the wings and tail might help to startle a predator at the moment of attack.
A Blue Jay taking off with an acorn
Flashing white in the wings and tail might help to startle a predator at the moment of attack.
■ Birds can be loud. For example, if a rooster crowed in your ear, the sound would be as loud as if you were standing two hundred feet from a jet engine. (Neither is recommended!) A lot of birds, like jays, make loud sounds, and a bird’s ear is less than an inch away from its mouth. So how do birds avoid damaging their own hearing when they call? Several things can happen more or less automatically when a bird calls. As the jaw opens, the external ear canal closes to shut out sound; increased air pressure in the inner ear helps dampen vibration; and the movement of a jawbone connected to the ear relaxes tension on the eardrum. Birds also have the ability to restore damaged hearing by growing new hair cells inside their ear, something humans cannot do.
Steller’s Jay calling
■ Sunning and anting are two different behaviors that are often confused. When sunning, a bird spreads its wings and fluffs its body feathers to bask in bright sunlight, especially on hot days. This is usually followed by a bout of preening. One likely benefit of sunning is that feather-degrading bacteria are inhibited by sunlight. Other possible reasons include converting vitamin D, and controlling feather lice (either by killing them or causing them to move, making it easier for birds to remove them by preening). In anting behavior, a bird sits among a swarm of ants in a contorted position, often with the tail bent under the body, grabs an ant in its bill, and wipes the ant along its feathers. Some evidence points to this being a kind of food preparation. The birds harass the ant to release its toxic formic acid, and once the acid is released the ant is edible. Formic acid does not have any known effect on feathers or feather parasites. But birds also wipe other acids such as lemon juice onto their feathers, so it is possible that acid has some still-unknown benefit.
A Blue Jay sunning (left) and anting (right)
■ Jays are sometimes seen knocking bits of light-colored paint off of houses and eating the paint chips. They are seeking calcium, which is an ingredient in most paint, and is especially important for female birds forming eggshells. Females of many species are known to select grit with higher calcium content in the spring when they are producing eggshells. This paint-chipping behavior is most prevalent in northeastern North America, where natural calcium is relatively scarce, partly because acid rain leaches calcium out of the soil. This behavior also occurs when there is deep snow cover, making any natural sources of calcium unavailable. You can help the jays (and stop them from chipping paint) by offering crushed eggshells, which are a better source of the calcium the birds need.
A Steller’s Jay eating paint chips