Nature Notes: Mixed Flocks

   On Sunday at noon while sitting in the living room counting cars going by on Noyac Road, there was a sudden spate of bird activity swirling around the front yard. There were purple finches, red-breasted nuthatches, white-breasted nuthatches, chickadees, titmice, a downy woodpecker, and a Carolina wren. They hung around for about 10 minutes before picking up and heading west — all except the Carolina wren, which was not part of the group.

    This was a typical winter, mixed traveling flock, going from feeder to feeder, wood to wood, yard to yard. There was no feeder to be found on my premises and so they stayed for only a short time picking at things here and there. Apparently they came by from next door, where Ellen Stahl has been generously feeding birds year after year. We stopped feeding three or four years ago after the rats began to outnumber the birds.

    The species of birds making up these roving winter flocks are all territorial come the spring and breeding activity. Robins and bluebirds are extremely territorial in the spring and summer. By fall they also flock up, but not with other species. They keep to themselves.

    Flocking, whether in mixed-species groups or within one species, has a lot to offer. There is strength in numbers, and members of a flock look out for each other in various ways. If one sees a predator, say, a hawk or cat, it immediately informs the others by uttering sharp warning notes. Soon all of the birds are taking cover in dense vegetation and some of them begin scolding, especially if the predator continues lurking about. Blue jays are usually part of these bands and they have the loudest, most aggressive calls, encouraging the others — notably the chickadees, nuthatches, and titmice — to join the chorus.

    The calls both confuse the would-be predator and tell all the smaller birds in hearing distance to be on their guard.

    If one of the flock finds a food source on its own, it shares it with the others, even though it may selfishly cache the seeds it doesn’t have room for in its crop in a secret place, like behind a piece of tree bark or in a tiny hole in a tree trunk. On the West Coast, the California woodpecker stores its acorns in special acorn-sized niches drilled into the trunk of a tree. It is not unusual when out hiking to come upon a tree trunk stuffed with acorns up and down and around, enough to get a woodpecker through an entire winter.

    Of course, other birds in the flock or outside of it are always looking for the food niches of the hiders and, undoubtedly, the hider loses a part of its stash throughout the long winter.

    Blue jays tend to store the acorns on the ground, under leaves or buried in shallow holes. Squirrels do the same. Like the blue jays, they remember where they put them here and there, but unlike the jays, which depend on their memories and eyesight, squirrels can sniff the acorns out. Sometimes the jays even watch where the squirrels hide their nuts, and vice versa.

    Feeders make everything easy, and one wonders if the birds don’t become lazy and assume an air of entitlement. I know of some yards with feeders where the feeder gets scolded by the jays and other freeloaders if the food is not forthcoming according to schedule.

    This fall has started out as few others in this millennium, as there are numerous northern birds among the feeding flocks. If you stock your feeder amply you are liable to not only get the common feeder birds — the house finches, house sparrows, song sparrows, gold finches, chickadees, et al. — but also the rarer ones like the crossbills, the grosbeaks, the redpolls, the purple finches, pine siskins, and maybe a sapsucker or two. Many of these are in town as this is being written.

    No doubt there will be squirrels, wild turkeys, and, eventually, Norway rats, but that is part of feeding. All things in nature big and small have to eat. All life also needs water. For bluebirds and robins, which like to glean their winter food from trees, bushes, and vines, water is more important than birdseed. Having just read what I wrote, I think it is time that I get over my rat phobia, promptly put up my feeders, and also get the watering holes going again. One cannot always depend on the rain to fill them. Next time, perhaps, the wandering flock will stop at my house for vittles first before going over to Ellen’s.