8 Animals that Build Nests (It’s Not Just Birds!)

american robin nesting with chicks
© yvontrep/Shutterstock.com

Written by Megan Martin

Published: December 14, 2023

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When you think of animals that build nests, your mind likely travels to birds. However, while it is true that birds are one of the most well-known animals to build nests, they’re not alone in this behavior. In fact, many species, from mammals to reptiles, also build nests! Continue reading to explore 8 of the animals that build nests.

More animals than birds build nests.


Eggs in the bird's nest. Crow's nest. Birdhouse in the tree.

Bird nests can come in a variety of shapes and sizes.

©Genc Subhan/Shutterstock.com

It wouldn’t be a list of animals that build nests without first highlighting the species most well-known for natural architecture. Not all birds build nests, and, of those birds that do, not every nest is equal. 

For example, compare the nests built by the California condor to that of the ruby-throated hummingbird.

The largest bird in North America, the California condor most often nests in natural cavities along cliffs, including caves. However, they may also nest in large trees, such as the coast redwood. Occasionally, California condors may lay their eggs directly on the ground if nesting in a cave or on a cliff ledge. When they do build a nest, however, they will create a loose nest made of gravel, leaves and barks, or even bones. The nest of the California condor is, on average, around 3 feet in width, with a depth of 8 inches.

In comparison, ruby-throated hummingbirds will also build a well-constructed nest, though they are much smaller than that of the California condor. These birds will build their nests on slender branches or man-made structures, such as chains or extension cords. They create an inner cup around the size of a thimble using thistles or dandelions. The pliable nature of these materials allows for the female to shape it as she pleases.

Regardless of shape or structure, the nests of birds, like many other animals, serve a shared purpose: providing protection and shelter for offspring. Many of the animals that build nests may not use them year-round, instead only building these intricate and interesting structures during the breeding season. 

Tree Squirrels

Kentucky grey squirrel sitting near its large nest on tall tree and branch Winter time urban wildlife photography 20109

The nest of a tree


is similar to that of a bird, although it is typically larger than most common backyard bird species.


When looking into a tree and seeing a large nest, it can be easy to think that the nest may belong to a bird. However, while this is always a possibility, tree squirrels will also construct their nests in trees.

There are two main types of tree squirrel nests. The first is the most common to see: the leaf nest. These nests are comprised mainly of leaves, although small twigs may be added throughout. Most often, squirrel leaf nests are found high up in trees, around 20 feet off the ground. Here, they are built in the fork of large branches. This helps provide stability for the nest and protection from strong winds and storms. Although these may look similar to the nests of some bird species, you can identify them because of their large size.

The second type of tree squirrel nest is those constructed within the cavities of trees. Most often, these cavities are created first by woodpeckers or other species. Natural processes may also lead to the creation of these cavities. These act as the preferred home for squirrels because of the protection they provide.


Raccoon Den

Along with building their own nests, raccoons will raise their offspring in tree cavities, human homes, and abandoned nests.

©Georgi Baird/Shutterstock.com

Squirrels aren’t the only mammals to make nests. In fact, raccoons may also build nests. Their nests are often found in trees, cavities, and similar locations. This species is opportunistic, in diet and habitat. As a result, with their natural wild habitats shrinking, you may also find them nesting in human areas such as chimneys or attics. Living in these areas also provides raccoons with the option to forage for food among trash cans and pet food, as well.

Raccoons will build their nest with a variety of materials, depending on what is available. As for many animals that build nests, leaves are a common option due to their availability, softness, and insulation qualities. However, while they may build their own nests, when available, raccoons will choose to take over nests abandoned by squirrels and birds. 


Some frogs will build a foamy nest to lay their eggs in.

©Bernard DUPONT from FRANCE / CC BY-SA 2.0 - Original / License

The grey foam-nest tree frog (Chiromantis xerampelina) is one example of a non-mammal or bird species that creates a nest. However, in contrast to the nest-building animals explained above, these frogs do not build their nest using leaves.

Instead, the grey foam-nest tree frog has a different approach to keeping its offspring safe. The nest-building process begins with the female excreting a thick, mucus-like substance. As she excretes this substance from the cloaca, she uses her hindlegs to introduce air into the liquid, whipping it into a bubbly, foamy froth. This substance is rather elastic, allowing the female to easily manipulate it into a nest. These foamy nests are found over water, where they will house the offspring until the eggs hatch. Then, the tadpoles will drop into the water where they will develop into adult, nest-building frogs to continue the cycle.


Fish will exhibit a variety of different nest-building behaviors.

©Chika Watanabe from Los Altos, USA / CC BY 2.0 - Original / License

Nest-building is a common behavior among freshwater and saltwater fish. However, unlike in many avian and mammalian species, it is the male that builds the nest. Nests are often used as a token of courtship, built in such a way as to impress potential mates. 

Nests will vary depending on the species. Betta fish, for instance, will build a foam nest similar to that of the grey foam-nest tree frog. However, instead of using a mucus-like substance hung on plants above water, betta fish will blow bubble nests that gather on the surface of the water.

Other types of fish nests include mound nests, nests built in empty shells, burrows, and woven nests.


Alligators are careful mothers that tend to the nest while waiting for their offspring to hatch.


One of the most surprising animals to build nests is the alligator. As with all reptiles, alligators start life as an egg. Alligators are soft, lacking the stiff outer shell of avian eggs. Because of this, the female alligator, who presents strong maternal instincts, will build a nest and care for her young until they are old enough to become independent. 

Alligators will build their nests on the shores of marshes and swamps, several feet away from the water and often in areas with an abundance of vegetation. An alligator nest is often around 6 feet in diameter. The materials comprising the nest may vary based on what is available, but vegetation and sticks are often used.

Sea Turtles

Baby sea turtles hatching from nest

Sea turtles bury their eggs, leaving their offspring to emerge from the nest after hatching.

©SLSK Photography/Shutterstock.com

Among reptiles, sea turtles are likely one of the most well-known animals that build nests. Each year, during the breeding season, coastal organizations and agencies spread an abundance of information about these species’ nest-building behaviors. Some groups may even go out onto the beach to locate and mark sea turtle nests to help prevent human interference. 

However, what does a sea turtle nest look like, and how do they build it?

Sea turtles take an entirely different approach not only to parent but nest-building than alligators. Because the female will leave her eggs, and consequently the offspring to fend for themselves, a protected nest is essential. During the night, the female sea turtle will emerge from the sea and crawl onto the beach. Little is known about why sea turtles will choose one beach over the other. She will construct what is known as a body pit by using her flippers to move sand. She will then lay her eggs into the cavity and cover it once more before returning to the ocean. 


Dinosaurs likely shared nesting behaviors with modern species like birds and alligators.

©Ballista at en.wikipedia / CC BY-SA 3.0 - Original / License

Although no longer roaming the Earth, dinosaurs, like other reptiles, once built nests. In fact, many remnants of fossilized dinosaur nests have been uncovered, including eggs. Although there is still much to be learned about the nesting behaviors of dinosaurs, it is likely they built nests and cared for their young in a way more similar to alligators and birds than sea turtles.

Summary of 8 Animals that Build Nests

2Tree Squirrels
7Sea Turtles

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About the Author

Megan is a writer at A-Z Animals where her primary focus is birds, felines, and sharks. She has been researching and writing about animals for four years, and she holds a Bachelor of Arts in English with minors in biology and professional and technical writing from Wingate University, which she earned in 2022. A resident of North Carolina, Megan is an avid birdwatcher that enjoys spending time with her cats and exploring local zoological parks with her husband.

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