Birds of a Feather
by Ro Wauer
The old adage that "birds of a feather flock together," referring to a flock composed of all the same species, is true much of the time, but not always. A quick look at anyone's bird feeder is certain to dispel this ancient adage. Feeders are attractive to a variety of species, especially those that utilize seeds. For instance, my seed feeders currently are supporting chipping, Lincoln's, and white-throated sparrows; mourning, Inca, and common ground- doves; Carolina chickadees; tufted titmice; pine siskins; American goldfinches; and northern cardinals. Even eastern phoebes and Carolina and Bewick's wrens hang around to sample insects that are attracted to the handouts.
My birdbaths are just as busy. They attract all of the above species as well as a number of non-seedeaters, such as robins, cedar waxwings, blue jays, mockingbirds, white-eyed vireos, and orange-crowned and yellow-rumped warblers. I have seen times when my birdbaths are circled by a mixed flock of robins and waxwings; they readily accept the other's presence.
Many birds do congregate in groups of a single species, although closely related species are also likely to be imbedded. For instance, various blackbirds, such as common and great-tailed grackles, cowbirds, and even redwings and starlings roost together. And robins, that return each evening to a favorite roosting site, tolerate a few additional species, such as waxwings, among them. Most of these birds also forage for food in a flock, especially during the winter months. The robin is the exception. Although robins roost overnight together in huge flocks, and usually go out together in the morning hours to find food, they seem to utilize separate feeding territories. This time of year, after they have claimed the majority of the ripe berries, they are spending considerable time alone, foraging for insects and earthworms. They actually partition their feeding grounds, a method that provides for a wider range of options and benefits the individual. Birds at a feeder do not require separation.
Flocking or "togetherness" is beneficial to various birds for several reasons. For instance, turkey vultures, a bird that usually roosts and feeds with others, also partitions its feeding grounds, often soaring alone while searching for carrion. This behavior allows them to cover a more extensive area. And when carrion is discovered by one individual, the others very soon gather together to take advantage of what the one individual has found. This same type of searching is also used by various pelagic birds that are required to cover an extensive area of ocean to find an adequate food supply. Once found, dozens of others, often including additional species, gather together to feed in what might properly be called a "feeding frenzy."
Another benefit of flocking, beyond the greater potential for finding food, is a defensive one. With an increased number of eyes, a bird in a flock is less likely to be caught by a predator; at least one member of the flock is likely to warn the others. At times, when a flying flock of individuals are widely spaced, they will suddenly close ranks (ball up) and even change direction on sighting a hunting raptor. The predator then is less likely to separate out one individual for capture. A sudden bunching will serve to form a solid wall that the predator will not want to dive through.
Anyone spending time in the field cannot help but marvel at a flock of flying birds that suddenly bunches up, flying at a great speed only inches away from another, and then veers one way and then another. Such flight is but one more of nature's wonders.