You might have heard of the nesting phase of pregnancy, where one or both parents go
through a lots of effort making the perfect space for their young one.
But birds go through a literal nesting phase before laying eggs, making the perfect space
for their chicks.
But what types of nests are there?
And how does each bird decide which one to make?
Let's collect some choice bits of information and see if we can build a nice, cozy understanding
of nests.
There are many types of bird nests, but they fit into some broad categories.
Here are some examples of each.
No nests
Emperor and King penguins do not make nests
at all, but stand still, holding their eggs on top of their feet.
There always has to be an exception to every rule in biology, and these penguins are it.
Scrape nests
Scrape nests are on the ground.
Not only that, they often are the ground.
This is the simplest actual nest possible, and many birds use it.
Gulls.
New World Vultures.
Sandpipers and other shorebirds.
Some penguin species also use scrape nests.
Burrow nests
Some birds burrow into the ground to make
a shelter.
Bank swallows dig using their beaks and wing feathers to push dirt.
Most species of kingfisher dig nest holes in the ground like these
ones are doing, though some kingfishers live in tree hollows instead.
Burrowing owls do not usually dig their own nests, but instead find a hole dug by a different
species and move in.
Some penguin species use burrow nests, also.
Low platform nests
These birds collect sticks and leaves and
pile them on the ground.
Grebes make floating nests in shallow water.
Some penguin species build low platform nests out of rocks.
Elevated platform nests
We're finally off the ground!
Some birds, like pigeons, make a pile of sticks and leaves and put them in a tree or cliff
face, or in this case, an apartment building.
This is what a pigeon nest looks like.
And here is a baby pigeon, called a squab.
If anyone asks you, you have now seen a baby pigeon.
Cup nests
This is the nest you would draw if someone
told you to draw a bird nest.
They sit somewhere secure like the fork of a branch, they are cup-shaped to keep the
eggs inside and warm.
There are many, many species that make this type of nest.
Robins are an example.
Suspended cup nests
Now we take the cup nest and hang it on the
side of a branch.
Vireos make this type of nest.
Pendulous cup nests
The cup nest is now hanging way down from
a branch.
Orioles make this style of nest.
Cavity nests
Why live on a tree when you can live IN a
tree?
Many birds use the safety and shelter of natural tree hollows.
Many owl species.
Wood ducks and some other waterfowl.
And some birds make their own hollows.
Woodpeckers are the famous ones, using their strong beaks to cut through wood.
Parrots also make their own hollows. Very slowly, but persistently, carving a wood cavity with its beak.
Those beaks are optimized for other tasks, but they do work.
Complex elevated nests
This category has lots of different nest types,
but they share the quality that they are up high, and harder to build.
These birds build nests that stick to the side of tall, smooth surfaces like cliffs
or buildings.
Swifts and swallows sometimes make nests out of mud, sometimes out of wood glued together
with dry spit, and sometimes they just build a nest out of dry spit with nothing else.
The Hornero These complicated nests are made of dry mud,
collected over the course of a few months and allowed to dry in the sun.
Really cool birds. Really cool nest!
The Oropendola builds big, hanging nests.
A colony can have around 100 nests, made of woven grass and
leaves.
Weavers weave nests out of grass.
The finished product is like a ball with openings that are just wide enough to let in the parents.
Males build a nest, or if they are really skilled, build several nests, and if females
like it they move in.
Their nests are pretty impressive on their own, but check out the sociable weaver nest.
This is the work of maybe thousands of individual birds, working on one permanent, giant nest
together.
It has around 100 individual chambers, and can provide a home to generations of weavers
for decades.
Weird nests
Because we're talking about living things,
there will always be some unique exceptions.
And I'm sure I've missed a few.
But these are the broad categories.
Choice
Why do birds choose one nest type or another?
There are a few factors.
One is what works.
If a nest on the ground is sufficient to raise healthy chicks, why bother building something
more difficult?
But another factor is predators.
You'll notice that each step up the nest complexity ladder offers more security to the chicks.
Starting on the ground, then out in the water, then up in a tree, then inside a tree, then
on a cliff face.
It's more difficult to construct these nests, but it's harder for predators to get to them,
which should mean more successful chicks.
The amount of time required to build a nest depends on how complex the nest is.
But it's a lot shorter than I thought it would be.
I expected it would take, like, a month to find the perfect nesting spot, then find all
the right materials and assemble them in the perfect configuration.
And then finally lay the eggs.
But it turns out that most songbirds get that done in two to ten days.
Woodpeckers can take a little longer, maybe three or four weeks, but they are literally
carving their nest out of wood with their faces.
You can see there's an amazing array of nest architecture, from the simple to the complex.
But every nest has the same basic function.
Which is to raise the next generation of young birds for us to learn about and appreciate.
Thanks for learning about birds with me.
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