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Some birds' nests are works of art. These are not those. But we'll see why the terrible nesting habits of the cuckoo or jacana or even pigeons are the right thing for their survival.

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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.

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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]