For some social birds, raising their young or finding food is a group effort. Learn more about cooperative bird behavior.
There are not many true loners in the bird world. Many types of social birds—from sparrows to sandpipers and gulls to goldfinches—will gather in flocks of their own kind, or with other species that share similar lifestyles. Being in a flock gives them safety in numbers, with more eyes to watch out for predators or other dangers.
We could say that their degree of social bird behavior is part of the personality of each species. But when birds gather, it isn’t just because they enjoy each other’s company. There are practical reasons that explain why some birds flock together and even work together.
Some social birds take it up a notch. Beyond just socializing, they actually work together in a coordinated way for the good of the whole group. Here are some examples of such clever, cooperative birds.
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Birds Hunting in Packs
For Harris’s hawks in southwestern deserts, hunting is a family affair. As many as six hawks, usually relatives, will target a rabbit, ground squirrel or other prey. They may swoop in from multiple directions at once, or one hawk may charge into a thicket to flush out an animal toward other hawks waiting just beyond. After the capture, the prey is shared among all the hawks in the group.
American white pelicans catch their dinner while swimming, dipping their heads underwater to scoop up fish in their huge bills. On northern lakes, pelicans cooperate by lining up side by side, dipping their bills in unison as they drive fish into shallow waters where they are easier to catch.
Group Nest Building Bird Behavior
For a pair of birds to successfully raise young, building a nest is an important step. Unfortunately for many species, there’s no attempt at teamwork: Female robins, cardinals and hummingbirds all build nests with no help from their mates. Even the intricate woven nests of orioles are all the mothers’ doing.
But the news about the guys isn’t all bad. Some males—including red-eyed vireos, mourning doves, red-tailed hawks, bald eagles and great blue herons—bring building supplies like twigs, grasses and plant fibers for the female to shape into a nest. Among some wrens, the male builds the main structure and the female adds the nest lining.
For one African bird, the sociable weaver, nest building is a task for an entire flock. A sociable weaver nest may look like a gigantic haystack draped over a short, sturdy tree. But up close, you can see dozens of small entrances on the underside, leading to individual nesting chambers. Sometimes more than a hundred pairs may help to build a single group nest—an almost unbelievable example of cooperative bird behavior.
Mother’s Little Helpers
It might seem logical to assume that eggs or young birds in a nest would be tended to only by their parents, but many nesting pairs are joined by extra helpers. For example, in the pygmy nuthatch populations of western mountain forests, about one-third of all breeding pairs are joined by one to three extra males—usually their own older offspring. These helpers bring food to the female while she incubates, and later bring food for the young. The brown-headed nuthatches of southeastern pine forests often have a similar arrangement.
American crows vary a lot in their nest-helping behavior. In some places, most adult crow pairs have helpers, and the number of extra birds can range from one or two to as many as 10. In other places, fewer than half the pairs are joined by helpers. These extra birds are usually, but not always, the pair’s offspring from previous seasons. They may stay with their parents for as long as six years before setting off on their own.
The same kinds of helpers have been observed in many other species, from purple gallinules to western bluebirds.
Seriously Social Bird Nesting
While these crows and nuthatches may or may not have helpers, Mexican jays in canyons of southern Arizona are committed to a group lifestyle. Living in flocks of five to 25 social birds, they defend permanent group territories and raise young as a social activity. Up to four females in the group may have nests with eggs at the same time. Other adults from the flock come to feed each incubating female. After the eggs hatch, the nestlings may be fed by most of the adults in the group, not just their own parents. Far away to the east, a similar social arrangement is often practiced by the Florida scrub-jay.
The groove-billed ani, a big black cuckoo found in Texas and the tropics, takes this group nesting to an extreme. Up to five pairs make up a breeding flock. Instead of building five separate nests, they work together to build one big nest, and all the females lay their eggs there. As a result, a single nest can hold as many as 20 eggs! All the flock members, both females and males, take turns incubating the eggs. All help to feed the young after the eggs hatch.
Champions of the Harvest
The ultimate cooperative bird in North America is the acorn woodpecker, a clown-faced climber of western oak woods. Not only do these woodpeckers nest in communal groups—with up to three females laying eggs in a single nest—they also work together to harvest food and store it for later.
Acorn woodpeckers are named for their favorite food, but in the oak woods where they live, acorns that fall to the ground are likely to be eaten by other animals or get lost in the dirt. So the woodpeckers create “granaries” in sturdy dead trees (or sometimes in utility poles), drilling dozens of neat round holes and placing a single acorn in each.
After storing acorns in fall, the woodpeckers feast on them during cold winter weather when other food supplies, such as insects, are hard to find. A woodpecker colony will continue to add more holes to the granary for years. One such site was estimated to have 50,000 holes!
Social Birds Ganging up on Predators
Most cooperative behavior involves just one species, but several unrelated kinds of birds may come together to mob certain types of predators. For example, when they discover a roosting owl in the daytime, a motley mix of wrens, chickadees, warblers, vireos and others will gather around, making loud alarm calls and even diving at the owl’s head. Alerted to the danger, other small birds can avoid the spot or join in the mobbing. They sometimes succeed in driving the owl away.
Watch Social Birds to Observe Their Behavior
These are just a few examples of the ways birds can work together. The avian world is full of fascinating behaviors. If you watch carefully, you may discover something new about the birds right outside your window. The cooperative habits of these birds are just a few of the many wondrous ways that birds can amaze and inspire us.
