The first thing to know is not that all birds make nests. For example, Emperor Penguin Fathers carry their precious egg on their feet (to keep it out of the frozen ground).
Some birds, like cuckoo, will lay their eggs in someone else’s nests. Others lay them on the ground among leaves or pebbles, or on cliffs with very little protection.
For birds that build nests, there is one main goal: to keep their eggs and chicks safe.
Many places to build a nest
Many birds also make their nests in tree hollows, including parrots. This is just one of the reasons why it is important not to cut down trees!
Meanwhile, kookaburras use their powerful beaks to burrow into termite nests and make a cozy nest inside. And the cute spotted pardelote dig small burrows on the side of earthen banks – with a safe and comfortable place for its eggs at the end of the tunnel.
Some birds, like brush the turkeys, spend months building huge mounds on the ground that can heat up from the inside. The male turkey makes sure that the soil is exactly the right temperature inside the mound, then lets the female lay the eggs inside. It will take large bites of soil around the eggs to check that they are not too hot or too cold.
What materials do they use?
Birds build many different types of nests. There are floating nests, cups, domes, pendulums and basket-shaped nests. They can be made from sticks, twigs, leaves, grasses, moss or even mud.
Magpie-larks (also called “peewees”), apostles and cabbage make mud bowl nests that look like terracotta plant pots. They do this by picking up mud and herbs in their beaks and shaking it to mix it with their saliva. They can then tie it to a branch and build upwards until the nest is complete.
In fact, bird saliva is a very strong, sticky material for building nests. Birds often mix saliva and mud together to make a type of glue. And some salangans make their nests entirely with solidified saliva. People will even eat these nests in bird’s nest soup!
Another kind of glue is used by Willie Wagtails – sticky cobwebs. They “sew” grasses together using cobwebs, and the webs also help keep nests strong against wind and water. They do, however, need to perfect the technique of picking the spider web, otherwise it can get tangled in their feathers.
Magpies and crows, both common visitors to our gardens, are also smart nest builders. Not only can they stack their sticks in a bowl, but they also use a lot of man-made materials in their nests. You might find them using fabric, string, or thread to hold a nest together.
Some birds such as red kites have even been seen “decorating” their nests with human debris. And Australian chatterers line the inside of their nests with a thick wall of kangaroo poop, followed by soft cuddly toys, to keep their chicks warm.
The construction process
To actually weave the nests, birds usually create a base by layering sticks or twigs where they want them. Then they use their beaks and feet to weave a chosen material, to hold the sticks in place.
They can pull strips of fabric with their beaks up and down, just like weaving a rug. They can even tie knots! Nests can take a long time to make, so they are often reused year after year. Weaver birds are so good at weaving that they can build intricate nests that cover whole trees and have multiple rooms.
To sum up, birds are really intelligent animals. They use their wits, along with their beaks and legs, to find the smartest ways to make nests with whatever materials are available. And they improve by learning from others, such as their parents or peers. DM / ML
This story was first published in The conversation.
Kiara L’Herpiniere is a PhD student and wildlife biologist at Macquarie University.