How to identify bird nests

There’s a lot of variation among size, shape and materials

|  Story by Meghan McMahon  |


When you spot a nest in a nearby tree or bush, it’s easy to assume it’s a robin’s nest, because robins are one of the most familiar of birds and one of the most common. Robins are also not very particular when it comes to building a nest, so you can find one almost anywhere. They will build their nests in trees and shrubs, but also gutters, eaves and other structures, according to the Cornell Lab of Ornithology.

Much like robins are the quintessential backyard bird, their nests are very much the quintessential nest. When you think of a bird’s nest, something very close to a robin’s nest is very likely what comes to mind. Robins build their nests with twigs, grasses and other materials, pressing them into a cup before adding mud to make it stronger and more stable. The last step is then lining the inside of the nest with fine grasses, according to Cornell Lab. A robin’s nest is usually about 3 inches to 6 inches tall and 6 inches to 8 inches across.


While a robin’s nest is the traditional grass-and-twig cup-shaped structure, not all nests are. Some birds make nests on the ground, called scrapes. Others nest in cavities and trees and other structures. Still others build large platforms for nesting. Some birds, such as the brown-headed cowbird, don’t use nests at all and instead lay their eggs in the nests of other birds. Even among those birds that do build traditional nests, there’s a lot of variation among size, shape and materials.

And not all birds are highly skilled nest builders. Mourning doves, for example, are known for their flimsy nests, said Jess McQuown, an interpretive naturalist at Four Rivers Environmental Education Center. And cardinals won’t be winning any nest-building competitions, although theirs are a step above mourning doves.

Here’s a closer look at the different kinds of birds nest we see among the birds that call Will County home, at least during nesting season.

Cup nests

A cup nest on the ground.

Blue-gray gnatcatcher nest (Photo by Chad Merda)

These are the nests we typically think of when we think of a bird’s nest — the prototypical nest built into the branches of a tree. It’s the most common type of bird nest, according to The Spruce, but there’s a lot of variation in size, nesting material and location.

While many cup nests are built in trees and shrubs, it’s not an exclusive choice. As mentioned above, robins aren’t too particular when it comes to choosing a spot to build a nest. They’ll pick a tree or a bush, but also maybe the eaves or rafters of a building. Barn swallows also build cup nests, but rarely in a tree or shrub. They usually choose nesting spots in the beams or rafters of buildings, or under bridges and culverts, according to Cornell Lab.


Materials also vary greatly in cup nests. Some, like barn swallows, use mostly mud to construct their nests, lining the cup with grasses and feathers. Blue-gray gnatcatchers use fibrous plant material to build their nests, then attach them to a branch using spider webbing. They also decorate their nests with lichens, Cornell Lab reports. Blue jays build their nests from twigs and grasses, sometimes adding mud. They prefer twigs from live trees and often have to work hard to gather their nesting materials.

Cup nests also vary greatly in size, with smaller birds building smaller nests and bigger birds constructing bigger nests. The nest of a ruby-throated hummingbird, the smallest bird we have in Will County, is tiny, about the size of a thimble.

A hummingbird's nest on the ground.

Hummingbird nest (Photo by Chad Merda)

A blue-gray gnatcatcher’s nest is bigger, but not by much. A crow’s nest, on the other hand, can be quite large, more than 1½ feet wide and more than a foot deep, according to Cornell Lab.

Cavity nests

Three young pileated woodpeckers poking their head out of a tree cavity.

Pileated woodpeckers (Photo via Shutterstock)

Woodpeckers are the most well-known cavity nesters, but they don’t always excavate holes for nesting themselves. Oftentimes, they will nest in an existing hole in a tree or other structure rather than create one themselves.

And while most woodpeckers — and all the woodpeckers that live in Will County — nest in cavities, they are far from the only birds that do. Bluebirds, chickadees and house sparrows also nest in cavities, according to The Spruce.If you leave bird houses or other bird boxes out in your yard, these birds will likely be the first to move in. They’ll make the place their own, though. For example, house sparrows typically stuff their nesting cavities with dried grasses and other materials until it is nearly full, Cornell Lab reports. Eastern bluebirds build loosely woven nests of grasses and pine needles in their cavities.

Ground nests

A killdeer sitting on its nest in rocks.

Killdeer nest (Photo via Shutterstock)

Not all birds build nests. Some instead creates scrapes on the ground to serve as their nesting spot. These scrapes are essentially shallow depressions in which they lay their eggs, according to The Spruce. Some birds may line the scrape with grasses, downy material or other debris, but not all do.

The most common ground-nesting bird in our area is the killdeer, which is a shorebird, although it is often found away from water. These birds create shallow scrapes on bare ground, and they often add bits of rock, sticks, shells and other debris, according to the Cornell Lab. The eggs themselves are buff colored and speckled, blending in with the surrounding ground.

Killdeer nests are not well protected because they are exposed on the ground, but the birds have a clever trick to draw danger away from their nests. They perform a broken wing display, pretending their wing is injured to draw predators and other dangers, like humans, away from their nests. Other birds that nest on the ground include a variety of shorebirds, from gulls and sandpipers to bobolinks.

Pendant nests

Two Baltimore orioles' nests on the ground.

Oriole nests; the one on the left is made from natural materials while the one on the right is made from synthetic materials. (Photo by Chad Merda)

Pendant nests are more elaborately woven than cup nests, and they have to be because they dangle off tree branches, which allows them to be safer from predators, according to The Spruce. Pendant nests are like delicately woven socks with a hole on the side where the birds can get in and out.

Baltimore orioles are one of the most well-known birds to use pendant nests. They build their nests high up in a tree, starting by hanging fibers over a branch that becomes knotted and tangled and then serves as the anchor. They typically use fine fibers such as grass, strips of vine bark and even horsehair, but they will also use artificial materials. In some cases, they will build nests entirely out of plastics and non-natural materials.


Unfortunately, though, these nests are not as stable and sturdy as those made from natural materials. Inside the nests, orioles will add a layer of feathers and downy material to serve as a cushion for the eggs and, eventually, the nestlings.  

Platform nests

Two great blue herons on a nesting platform at Lake Renwick.

Great blue heron nest (Photo by Chad Merda)

Larger birds build larger nests, and many of the large birds we see locally build large platform nests. These nests are typically big and bulky, composed of larger sticks and structures than we see in cup nests, according to The Spruce. Birds that utilize platform nests tend to use them over and over again rather than selecting a new nesting site every year or for each brood of eggs.

Among the birds locally that build platform nests are great blue herons, bald eagles, ospreys and other raptors and large wading birds. A good place to see these kinds of nests is Lake Renwick Heron Rookery Nature Preserve, which is home to many platform-nesting birds. The preserve is open to the public from 8 a.m. to sunset daily from August 16 to February 28. From March 1 to August 15, it is closed to protect the nesting activities of migratory birds.

(Lead image via Shutterstock‎)


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