By
Viewed
495,175
Please choose the correct answer for each question below:
Questions: 0/249
Correct: 0
Translate:
Birds’ nests are a work of art.
From the intricate apartment
complexes of the sociable weaver bird
to the massive, maintained-for-life
nests of bald eagles,
many nests are masterpieces.
But some of them aren’t quite as impressive.
In fact, they’re downright pitiful.
Some nests are built so badly that
they straight up fall out of trees.
Like, I don’t even know if
we can call it “building”
with the shoddy work some of these birds put in.
Whether it’s a horrible choice of material
or a general lack of
construction, it’s hard to imagine
that these nests have any redeeming qualities.
But when you learn the full story,
it turns out that there are good reasons
for these birds’ seemingly terrible choices.
So here’s why these nests are so so bad:
[♪ INTRO]
Hummingbirds make really cool nests out of moss.
Moss is a great building material
because it retains moisture
and keeps their eggs from drying out.
Meaning moss itself isn’t the problem here.
But certain hummingbirds will only
build their nests out of this,
which is the /rarest/ moss they can find.
Which seems like a big risk if you run out of it.
100% of the hummingbird nests sampled
in a study conducted in Chile used this rare moss.
And they didn’t just use it as an accent.
They used it to build their nests. 97% of each
nest was made of this special stuff.
And the forest that these hummingbirds
live in is covered in moss.
So it’s not like they were all out of options.
They just chose to build their nests out of this
absurdly rare kind of moss that only makes up
0.1% of the moss that they
could find in that forest!
It’s like looking at a bunch of
piles of wood and clay and stone
and going, you know what I’m
going to build my house out of?
Meteorites.
So there must be something special about this moss
that makes it worth the
trouble. We just couldn’t see
what that advantage was without a microscope.
Turns out, this particular moss
has antimicrobial properties!
So it keeps the nest safe from
pathogens like staph and E. coli.
The other moss in the forest?
Useless against those bacteria.
And it’s not just bacteria. This
special moss was shown to keep fungi,
insects, and even small mammals away too.
In other words, the birds are
being fussy for a reason –
they seem to recognize that this
moss is good for Junior’s health.
The secret lies in its chemistry.
It’s full of compounds that all
of those organisms can’t stand.
And since these compounds are polar,
they dissolve into water and
tend to do their best work
in wet environments, which
the moss helps to maintain.
So, yeah, any moss could probably
keep the nest nice and juicy.
But only this rare moss has
a molecular KEEP OUT sign
to ward against potential threats.
Even when researchers were
storing the different moss samples
in their lab, they noticed that the
rare moss didn’t rot like the others.
So despite being able to provide
similar structural function,
the more abundant mosses just don’t
hold up against this super rare moss.
Hummingbirds put in the extra effort because
it’s probably helping keep their babies alive.
That’s a theme jacanas may be familiar with.
Although they might go about
the same goal the opposite way.
Instead of searching endlessly
for the rarest materials,
pheasant-tailed jacanas
kind of just plop their eggs
onto some grass found in their breeding grounds.
No fanfare. No intricate weaving.
Although sometimes
pheasant-tailed jacanas will make
more substantial bowl-shaped
nests, sometimes they don’t.
Which seems pretty neglectful
when you consider the location.
Jacanas breed on the water’s surface.
Yes, they could make their
nests on solid ground nearby.
But at least pheasant-tailed jacanas choose
this precarious situation instead.
To their credit, look at them. They
were kind of made for that life.
They have these long legs and sprawling feet that
make them pretty well adapted to walk on water.
It even earned them the nickname “Jesus bird.”
But that doesn’t mean their
eggs are as well adapted
to life on the water. Jacana
eggs are sitting ducks out there!
…Or you know what I’m saying.
They’re pretty exposed to both predators
and the elements on these flat nests.
To protect their babies, instead
of building sturdy nests,
an adult will shove their wing
under the eggs to keep them safe
and incubated close to their body.
So the nests are pretty useless.
Until it floods.
Pheasant-tailed jacanas make
their nests on both rooted
and unrooted grass that extends out of the water.
So the eggs often end up partly underwater.
Which, I promise, is a good thing.
It keeps them from drying out.
The critical word here is “partly.”
Jacana eggs would be in
trouble if they took a swim.
Developing bird embryos need
oxygen just like anything else,
and eggshells let a little air pass through.
So when the water levels start to rise,
the nests of unrooted grass rise too
and keep the eggs from
drowning. Like little buoys.
And when the water really starts flowing,
it could carry the eggs downstream.
But since the eggs are on flat nests,
they can be easily rolled onto a
more stable surface to keep them safe.
And that’s exactly what
the supervising adult does.
So these unstructured excuses
for nests might just be the
smartest way to stay afloat in a
constantly changing environment.
Excuse the interruption, but
I have got some good news.
Well, it’s actually Good Good Good news.
Good Good Good are the people
who bring you the Goodnewspaper,
where the news doesn’t have to be
draining; in fact, it can be hopeful!
The Goodnewspaper is the print
newspaper designed to leave
you feeling more hopeful and
better equipped to do more good.
Yes, it’s a print newspaper. Those still exist!
And you’ll receive it in the mail!
So going through your physical
mail can be enjoyable again.
I mean, the design alone is enough
to brighten up your pile of snail mail.
But on top of the newspaper itself,
each edition comes with a centerfold poster
you could, like, hang on your wall.
Plus, every newspaper is printed on
recycled paper using soy-based inks.
Good Good Good is Climate Neutral and a member
of 1% for the Planet, so they proudly donate
to climate justice organizations. Which means
you’re doing good just by getting the paper!
Each one of us, like, can only do so much, right?
But the Goodnewspaper reminds us that when
we do small good things together,
we can make a bigger impact.
You can check them out at
goodnewspaper.org/scishow.
And SciShow viewers get your first Goodnewspaper
for just $5 and can cancel any time.
Alright! Let’s get back to the show.
If you thought jacana nests were sad,
just wait until you hear about
croaking ground-dove nests.
I’ve never seen the word “flimsy”
used so much in academic literature.
But that’s how bad these doves are at
making structurally sound nests.
And there are real stakes here.
See, doves like croaking
ground-doves lay their eggs
in nests as high as 20 meters off the ground.
But they don’t do much to keep
the eggs there by finishing off
the nest with sides or any of the
other silly little foundational things
that some other birds include in their nests.
And when things like, you know, wind happen,
eggs can fall from high places.
So you’d think they would try a little harder.
And we’re still not entirely sure why they don’t.
But in a related species, the mourning dove,
researchers think this kind
of nest building behavior
could be evidence of an
evolutionary trade-off at work.
The birds may be making a calculation:
Whose life is worth more,
the eggs or the egg layer?
The mourning dove researchers
suggested that if the eggs
fall out of the nest, the
mama bird can lay more eggs.
But to make a better nest, the mama bird would
be exposing themself to predators for longer.
As it turns out, there are
measurable consequences.
A study conducted in Maryland, USA, found that
flimsy nests really do affect the
survival rates of mourning doves.
Now, there are loads of different kinds of doves,
so we can't have one species speak for them all.
But in this case, it seems like a pretty similar
scenario between these two species.
So that’s one explanation
for building a flimsy nest.
But another might be that they’re
not really as flimsy as we thought.
A study conducted in Ecuador found that sometimes
croaking ground-doves do make sturdier nests.
And one factor that determined whether a nest
was poorly or well constructed
as what it was built on.
More robust nests were built
on precarious branches.
The flimsiest twig platforms, on the other hand,
were built on really stable
branches that don’t need
a lot of extra finessing to provide support.
So they might only make more secure
nests when they really need to.
Which means when we judge the doves for making
truly pathetic nests, it might
be a superficial dig at them.
In the end, maybe they're not
incompetent nest builders –
they're smart site-choosers!
Cowbirds appear to make much more thorough
assessments of other birds’ nests than we do.
Because they lay their own eggs there.
The brown-headed cowbird nest is on
this list because it doesn’t exist.
These birds aren’t even trying to make
a nice place for their babies to hatch from.
Instead, they do something
called brood parasitism,
and drop their eggs off in other
birds’ nests for them to deal with.
Some brood parasites have
a longstanding relationship
with a specific species of bird that
they know will be good babysitters.
Like, the yellow-throated cuckoo only
parasitizes the grey-throated tit-flycatchers.
But not the brown-headed cowbird.
They’ll put their eggs
anywhere including, presumably,
the other terrible nests
we’ve already talked about.
Cowbirds, I’m begging you. Standards.
This kind of random brood parasitism seems like
it could be a bad strategy
because it’s a toss up whether
the parent you left your eggs with
will actually raise your babies.
But it might just be the best possible strategy
to keep their chicks hatching
in a constantly changing world.
With the global climate crisis,
temperatures are all over the place.
And by spreading their eggs across
multiple baskets, I mean nests,
cowbirds might be able to persist
in a variety of weather situations.
In a 2020 publication, researchers
said they’re basically hedging
their bets by putting a few eggs
over here and a few over there.
And their analysis suggested that
this is the smart way to go about it.
At least some of those eggs will probably hatch.
See, with a changing climate,
the start time for Spring is also changing.
And if both you and the bird you’ve chosen
to raise your babies start migrating earlier,
then there won’t be anyone around to make
sure your chicks actually hatch.
Instead of being stuck in their ways,
building nests the same way
generation after generation,
these birds’ laziness makes them adaptable.
The final birds of this video are also adaptable.
And they’re spiteful on top of it.
Okay, so it’s hard to empirically
measure the amount of spite
in an avian species, but
listen to this and tell me
these birds aren’t doing it on purpose.
Eurasian magpies in Belgium have been known
to make their nests almost
entirely out of anti-bird spikes.
You know the pokey metal things that some people
put on buildings and other
structures to keep the birds away?
Yeah, these birds rip them off of buildings
and make their nests with them.
Which, yes, is the ultimate form
of giving the bird to someone.
But it seems like probably the worst material
they could possibly use to
build their nursery out of.
Until you think about how much birds also
want to keep birds out of their spaces.
When they put these spikes on
the outside of their nests,
they could be using them to keep
crows from eating their eggs.
But some birds put the
spikes facing into the nest,
and while that looks even worse
for their little hatchlings,
it might just be a way to secure the nest in place
and maintain its structure. Like they’re using
these spikes as safety pins.
So researchers think that
this incredibly dangerous
building material might be
good for more than pure spite.
Now, those five birds might look like the
biggest doofuses in the nesting world.
But in each case, there’s a
logical reason to do what they do.
Maybe this list of the worst
nest builders is really a list of
the top animals that flip our
perception of the world on its head.
[♪ OUTRO]
Related Songs