Note: this is the full article by Guest Contributor MELISSA BLOCK. An excerpt is featured in the March/April 2019 edition of our Bird’s-Eye View Newsletter
NEST DESCRIPTION : Cardinals
Males sometimes bring nest material to the female, who does most of the building. She crushes twigs with her beak until they’re pliable, then turns in the nest to bend the twigs around her body and push them into a cup shape with her feet. The cup has four layers: coarse twigs (and sometimes bits of trash) covered in a leafy mat, then lined with grapevine bark and finally grasses, stems, rootlets, and pine needles. The nest typically takes 3 to 9 days to build; the finished product is 2-3 inches tall, 4 inches across, with an inner diameter of about 3 inches. Cardinals usually don’t use their nests more than once.
A week or two before the female starts building, she starts to visit possible nest sites with the male following along. The pair call back and forth and hold nesting material in their bills as they assess each site. Nests tend to be wedged into a fork of small branches in a sapling, shrub, or vine tangle, 1-15 feet high and hidden in dense foliage. They use many kinds of trees and shrubs, including dogwood, honeysuckle, hawthorn, grape, redcedar, spruce, pines, hemlock, rose bushes, blackberry brambles, elms, sugar maples, and box elders.
NEST DESCRIPTION : House Wrens
House Wrens pile twigs into the cavities they choose to nest in, either to make a bed on which to build a soft-lined cup, or sometimes mounded up into a barrier between nest and entrance, seemingly to protect the nest from cold weather, predators, or cowbirds. The cup itself is built into a depression in the twigs and lined with just a few grams (less than 0.25 oz) of feathers, grasses and other plant material, animal hair, spider egg sacs, string, snakeskin, and discarded plastic.
House Wrens nest in old woodpecker holes, natural crevices, and nest boxes (or discarded tins, shoes, etc.) provided by humans. This bird’s association with open woodland is reflected in its choice of nest sites: it rarely uses nest sites more than 100 feet from woody vegetation, but also avoids heavily wooded nest sites where it’s hard to see predators coming. Despite their small size, they can be fierce competitors for nest sites, sometimes evicting a larger species and claiming its cavity after the bird has already begun nesting.
NEST DESCRIPTION : Chickadees
Both male and female chickadees excavate a cavity in a site usually selected by the female. Once the nest chamber is hollowed out (it averages 21 cm deep) the female builds the cup-shaped nest hidden within, using moss and other coarse material for the foundation and lining it with softer material such as rabbit fur.
Nest boxes, small natural cavities, or abandoned Downy Woodpecker cavities; often excavate their own cavities. In the case of next boxes, seem to prefer to excavate wood shavings or sawdust rather than to take an empty box. Nests can be at ground level to more than 20 m high, but are usually between 1.5 and 7 m high. They tend to excavate in dead snags or rotten branches, and often select alder or birch.
NEST DESCRIPTION : House Finches
A House Finch’s nest is a cup made of fine stems, leaves, rootlets, thin twigs, string, wool, and feathers, with similar, but finer materials for the lining. Overall width of the nest is 3-7 inches, with the inside cup 1-3 inches across and up to 2 inches deep.
House Finches nest in a variety of deciduous and coniferous trees as well as on cactus and rock ledges. They also nest in or on buildings, using sites like vents, ledges, street lamps, ivy, and hanging planters. Occasionally House Finches use the abandoned nests of other birds.
NEST DESCRIPTION : Robins
Females build the nest from the inside out, pressing dead grass and twigs into a cup shape using the wrist of one wing. Other materials include paper, feathers, rootlets, or moss in addition to grass and twigs. Once the cup is formed, she reinforces the nest using soft mud gathered from worm castings to make a heavy, sturdy nest. She then lines the nest with fine dry grass. The finished nest is 6-8 inches across and 3-6 inches high.
NEST DESCRIPTION : Goldfinches
The nest is an open cup of rootlets and plant fibers lined with plant down, often woven so tightly that it can hold water. The female lashes the foundation to supporting branches using spider silk, and makes a downy lining often using the fluffy “pappus” material taken from the same types of seedheads that goldfinches so commonly feed on. It takes the female about 6 days to build the nest. The finished nest is about 3 inches across on the outside and 2-4.5 inches high.
NEST DESCRIPTION : Orioles
Baltimore Orioles build remarkable, sock-like hanging nests, woven together from slender fibers. The female weaves the nest, usually 3 to 4 inches deep, with a small opening, 2 to 3 inches wide, on top and a bulging bottom chamber, 3 to 4 inches across, where her eggs will rest. She anchors her nest high in a tree, first hanging long fibers over a small branch, then poking and darting her bill in and out to tangle the hank. While no knots are deliberately tied, soon the random poking has made knots and tangles, and the female brings more fibers to extend, close, and finally line the nest. Construction materials can include grass, strips of grapevine bark, wool, and horsehair, as well as artificial fibers such as cellophane, twine, or fishing line. Females often recycle fibers from an old nest to build a new one. Males occasionally bring nesting material, but don’t help with the weaving. Building the nest takes about a week, but windy or rainy weather may push this as long as 15 days. The nest is built in three stages: first, the female weaves an outer bowl of flexible fibers to provide support. Next, springy fibers are woven into an inner bowl, which maintains the bag-like shape of the nest. Finally, she adds a soft lining of downy fibers and feathers to cushion the eggs and young.
Oriole-The female chooses a nest site within the territory defended by her mate. She anchors the nest firmly to a fork in the slender upper branches of a tree. Baltimore Orioles often nest in American elms, but will build in other trees, especially maples and cottonwoods. The distinctive nest usually hangs below a branch, but is sometimes anchored along a vertical tree trunk.
NEST DESCRIPTION : Hummingbird
The nest is the size of large thimble, built directly on top of the branch rather than in a fork. It’s made of thistle or dandelion down held together with strands of spider silk and sometimes pine resin. The female stamps on the base of the nest to stiffen it, but the walls remain pliable. She shapes the rim of the nest by pressing and smoothing it between her neck and chest. The exterior of the nest is decorated (probably camouflaged) with bits of lichen and moss. The nest takes 6-10 days to finish and measures about 2 inches across and 1 inch deep.
Females build their nests on a slender, often descending branch, usually of deciduous trees like oak, hornbeam, birch, poplar, or hackberry; sometimes pine. Nests are usually 10-40 feet above the ground. Nests have also been found on loops of chain, wire, and extension cords.
NEST DESCRIPTION : Downy Woodpeckers
Downy Woodpeckers nest in dead trees or in dead parts of live trees. They typically choose a small stub (averaging around 7 inches in diameter) that leans away from the vertical, and place the entrance hole on the underside. Nest trees are often deciduous and the wood is often infected with a fungus that softens the wood, making excavating easier.
Both male and female excavate the nest hole, a job that takes 1 to 3 weeks. Entrance holes are round and 1-1.5 inches across. Cavities are 6-12 inches deep and widen toward the bottom to make room for eggs and the incubating bird. The cavity is lined only with wood chips.
NEST DESCRIPTION : Hairy Woodpeckers
Hairy Woodpeckers typically excavate their nests in the dead stub of a living tree, especially trees with heartrot, or in a dead tree. The cavity is often in a branch or stub that isn’t perfectly vertical, with the entrance hole on the underside. This location may help keep flying squirrels and sapsuckers from trying to take over the hole. Hairy Woodpeckers begin excavating their nests less than 2 weeks before egg-laying begins.
The entrance to the nest is about 2 inches tall and 1.5 inches wide, leading to a cavity 8-12 inches deep. The inside widens at the bottom to make room for the eggs and the incubating bird. It’s typically bare except for a bed of wood chips at the bottom for the eggs and chicks to rest on.