Birds’ nests in autumn – the big reveal

Nov 26, 2014

by Steve Blight

Many people find it a bit sad to see the leaves fall after the glorious display our trees put on in September and October. However one of the benefits of the landscape’s new leaflessness is that lots of birds’ nests have now been revealed. In this column I will provide a brief description of the nests of a number of birds that are likely familiar to many readers. Most of the birds I’ve described are tree nesters, but I added a couple of others because they are familiar to many people and they also help illustrate the interesting range of nesting sites that birds use.

American Robin nests are typically found in the lower half of a tree, often on a horizontal branch hidden by a layer of dense leaves. Robins also nest in gutters, eaves, on outdoor light fixtures, and other structures. Female robins choose the nest sites and build the nest from the inside out, pressing dead grass and twigs and other materials into a cup shape. Once the cup is formed, she reinforces the nest using soft mud to make a heavy, sturdy nest and lines it with fine dry grass.

Black-capped Chickadees typically excavate a cavity in a site usually selected by the female. She then builds the cup-shaped nest in the chamber using moss and other coarse material for the base and lines it with softer material such as rabbit fur. Nests are usually between 5 and 20 feet high. They tend to excavate in old standing dead trees or rotten branches, often selecting alder or birch. Nest boxes, small natural cavities or abandoned Downy Woodpecker cavities can be used as well.

American Crows. Both members of a breeding pair of crows help build the nest. Interestingly, young birds from the previous year sometimes help as well. The nest is made largely of medium-sized twigs with an inner cup lined with pine needles, weeds, soft bark, or animal hair. Nest size is quite variable, but typically ranges from 6-19 inches across. Crows typically hide their nests in a crotch near the trunk of a tree or on a horizontal branch, generally towards the top third or quarter of the tree. They prefer to nest in evergreens, but will nest in deciduous trees when evergreens are less available.

Eastern Phoebe. As I write this, I am looking through one of the windows in our house at a phoebe’s nest from last summer located on a horizontal beam under our deck. This is a typical location for a phoebe’s nest – built in niches or under overhangs, where the young will be protected from the elements and fairly safe from predators. Nests are typically less than 15 feet from the ground and built close to the roof of the alcove they have chosen. Only the female builds the nest, often while the male accompanies her – presumably waiting for instructions. She constructs the 5-inch-across nest from mud, moss, and leaves mixed with grass stems and animal hair. Unlike most birds, nests are often reused in subsequent years. The nest at our house was used to raise 2 broods of babies over the summer for a total of 10 new phoebes added to the population.

Baltimore Orioles build remarkable, sock-like hanging nests, woven together from slender fibers. Construction materials for the 3 to 4 inch deep nest can include grass, strips of grapevine bark, wool and horsehair, as well as artificial fibers such as cellophane, twine, or fishing line. The female chooses the location and weaves the nest, anchoring it high in a tree, often an elm but increasingly in other tall trees like maples or poplars. The distinctive nest usually hangs below a branch.

Blue Jays build an open cup nest of twigs, grass, and sometimes mud, lined with rootlets. Their nests are typically in the crotch or thick outer branches of a deciduous or coniferous tree, usually 10-25 feet above the ground. Male and female both gather materials and build the nest, but on average the male does more gathering and the female more building. Twigs used in the outer part of a nest are usually taken from live trees, and birds often struggle to break them off. Birds may fly great distances to obtain rootlets from newly fallen trees or human construction sites.

Red-winged Blackbirds typically nest in marshes. Females choose the site and build the nest near the ground (or water surface in a marsh), in dense, grass-like vegetation such as cattails, bulrushes, and sedges. Females wind stringy plant material around several close, upright stems and weave in a platform of coarse, wet vegetation. Around and over this she adds more wet leaves and decayed wood, plastering the inside with mud to make a cup. Finally, she lines the cup with fine, dry grasses. When finished the nest is 4 to 7 inches across and 3 to 7 inches deep.

American Goldfinches build an open cup nest from rootlets and plant fibers lined with plant down, often woven so tightly that it can hold water. Male and female goldfinches jointly choose a suitable nest site but the female builds the nest, usually in a shrub or sapling in a fairly open setting. The nest is often built high in a shrub, where two or three vertical branches join; usually shaded by clusters of leaves from above. The female lashes the foundation to supporting branches using spider silk, and lines the nest with the fluffy material from the seed heads of plants like thistles and milkweeds. The finished nest is about 3 inches across on the outside and 2-4.5 inches high.

Photo: Ruby-throated Hummingbird nest. The nest opening is about the size of a penny Photo taken by Steven Kapusta, Ontario Hummingbird Project

Ruby-throated Hummingbirds  Females build their open cup nests on a slender, often descending branch, usually of deciduous trees like oak, ironwood, birch, poplar or sometimes pine. About the size of a 1/3 cup measuring cup, it’s made of thistle or dandelion down held together with strands of spider silk and sometimes pine resin. The female chooses the location and does all the nest construction. She decorates (camouflages?) the exterior with bits of lichen and moss. The nest takes 6-10 days to finish and measures about 2 inches across and 1 inch deep.

This is only a very brief introduction to the nest-building habits and habitats of a few of our local breeding birds. However, I hope it provides readers with a taste of the wide range of nesting sites and materials used, and a few clues to help identify any nests that people might encounter now that the leaves are gone and before the winter weather tears apart the nests left behind. In a future column, I’d like to share some information on a totally different nesting strategy – nesting on the ground – and some readers may be surprised to learn about a few of our local birds that use this strategy.