Now that the leaves have fallen from the trees, it’s easier to see all the bird nests that served as home for a variety of birds last summer. They didn’t all build their nests in trees, though. A robin built one up in the corner of the house just outside the bedroom window. A Baltimore oriole built its signature hanging nest in tree, and inside the old shed, a barn swallow built its mud nest against a beam. Another bird of some sort built a nest inside the exhaust pipe for the furnace. This was not the first time that happened, but hopefully it will be the last as we’ve covered the ends of the exhaust and air intake pipes with mesh to keep the birds out.
Woven basket nest of Baltimore Oriole stands out from the walnut after the tree defoliated in the fall. Author photo.
The mud and grass nest of a barn swallow sticks to the side of a joist in the shed. Author photo.
The birds that live on, or frequent, Owl Acres have various strategies for building their nests. They all have the same goals, though—to create a place where they can lay their eggs, incubate them, hatch them, and provide a safe space where their offspring can grow and learn and fledge. They need a sheltered or camouflaged space where predators can’t get at them. They need a space that retains the heat incubation requires. They need enough room to support their eggs and hatchlings. And they need a source of food nearby that they can feed to the hungry peeping mouths of their chicks. In most cases, the nests also serve the purpose of holding the eggs safely, keeping them from falling out. However, every species has its own ideas about how to meet these needs.
Turkey vultures, for instance, don’t bother to build a soft cushy nest for their babies. They spend time finding the right place to lay an egg, and then just lay it on the ground or in the tree. Somehow this seems appropriate for turkey vultures. Wild turkeys also nest on the ground but take more time to make a nest before laying their eggs. Brown-headed cowbirds don’t build a nest at all. They just lay their eggs in somebody else’s nest. Mourning doves seem to be in a great hurry when they throw their nests together. They throw some sticks, grass and maybe some pine needles together on whatever platform they can find—the horizontal crotch of a branch, or last year’s robin’s nest. The nest is so flimsy that the eggs can actually fall through the cracks. Bald eagles, on the other hand, may spend months creating a platform for their nests. They’ll build a great mound of sticks and other materials high in a tree. Then they’ll create a shallow depression in the top where the eggs will actually be laid, and the eagles will use the same nest year after year, repairing and enlarging it in time for egg-laying.
Barred owls are cavity nesters, preferring to nest in holes high up in trees. The holes are usually the work of one of the five species of woodpeckers that frequent Owl Acres. The woodpeckers make the cavities in trees or fence posts for their own use, and other birds or squirrels take over the next year. Some, like the tufted titmouse, build cup-shaped nests inside the cavity. They build a cup with twigs and grass and then line it with softer grasses and animal hair. Others, including the woodpeckers, just lay their eggs on the floor or on the wood chips made by the excavators. The white-breasted nuthatch also likes a cavity and goes to some trouble to make it feel like home. She lines the hole first with dirt, bark and fur. Then she’ll build a cup-shaped nest of bark, fur, grasses and twigs and line it with feathers, fur and other soft materials. European starlings are not shy about driving birds out of these cavity nests and taking over the nest for themselves.
Cup-shaped nests on tree branches are the most familiar on Owl Acres. They’re carefully camouflaged during the breeding season, hidden among the leaves of the trees. Tiny hummingbird nests high in the trees, for instance, are nearly impossible to find. These compact little nests are made of twigs and plant fibers woven together with spider silk. The ruby-throated hummingbirds on Owl Acres attach their little nests to small, downward-bending branches with more spider silk. Then they cover the outside of the nest with gray-green lichens to provide even more camouflage. As the nestlings grow, the nest is designed in such a way that it expands to give them more room.
Cardinals, like many other birds on Owl Acres also build cup-shaped nests. The female softens twigs by chewing them, making them pliable, then weaves together a roughly cup-shaped creation. She lines it with soft grasses, fur, leaves and pine needles. Then she gets into the nest and turns around and around, stamping her feet, forming the nest to her body.
Inside the old shed where we keep firewood and the little tractor, barn swallows have built their nests of mud plastered to the beams.
Perhaps the most distinctive and interesting nest on Owl Acres this year is the Baltimore oriole’s nest. Shaped like a four-inch-deep pouch attached to a branch, it is intricately woven. Using her feet and her beak, the nest-builder manipulates grasses, twine, string, twigs and other fibers, weaving them together and tying knots strategically to create a very dense and compact outer shell. Once that’s finished, she moves to the inside of the nest to create a second layer. For this layer, she uses springy fibrous material like milkweed and grapevine. When that’s done, she weaves yet a third interior layer of softer materials like grass, fur, and feathers. The nest is hung from the tip of a thin branch, making it hard for climbing predators to get at it. Being pouch-shaped instead of an open cup, the nest and its contents can also survive being buffeted by wind and storms. Where the mourning dove spends as little as a few hours throwing her nest together, the Baltimore oriole may take up to twelve days to complete her intricate creation.
Most of the work that went into building these little homes will be lost as winter winds toss them about. It’s humbling, though, to think about the skill and precision that goes into each one and the reality that each strategy exactly fits the needs of the builder. And if we’re lucky, they’ll be back next spring to do it again.
Wire baskets close off the plastic furnace pipes on the side of the house. These have been attractive nesting sites for birds, and expensive technician calls when the furnace doesn’t start in cold weather! Author photo.
Feature Photo by Author. Alt text: A robin has built its nest braced between the downspout and red siding on the house next to the bedroom window