Why bird nests aren't covered in poop

so i want to show you something that is bringing me joy right now because it is spring this little bird nest has a little egg in it that was me a few months ago that's crazy right after i discovered this bird's nest with a single bright blue egg sitting on this porch swing a few days later it had four eggs guess what happened next they hatched and you better believe i named them this is goose pepper jack dot and rocco for a few weeks when i was really bored during lockdown i watched these little baby birds grow and grow and grow and i started to film them and they let me get really close i even filmed them in slow motion you'll find out later why as i watched them grow a million questions popped in my head why is this egg blue how long do the eggs take to happen what type of bird is baby [Music] but my biggest question how was this tiny little nest not full of poop [Music] to answer all my questions i tracked down this guy my name is michael murphy i'm a professor of biology at portland state university in portland oregon he's an ornithologist which means he studies birds my personal interest is in behavior of birds and the population biology of birds and when he says birds he means a lot of birds tree swallows barn swallowers cliff swallows eastern phoebes spotted towies i've worked on a species known as the eastern king bird since 1979 as you can see i have a tattoo of the creek there he studies all of their behaviors like where they sleep what they eat and how they travel and he also knows a lot about bird poop which brings us back to the eggs i found on my porch so what type of birds are in these eggs well that was an american robin when it grows up it's got this fiery orange belly it's impressive this animal um breeds across an enormous swath of north america it travels as far north as alaska to breed in the springtime and as far south as mexico during the cold winter months that's over five thousand miles it seems as long as you've got a structure it can put a nest on and as long as it can get some good mud to build a nest you're gonna find it so it's just extremely adaptable so let's walk through the life of my porch robins first they're just four little eggs why are they blue well that's a big question [Music] the coloration of bird eggs is extremely variable what we do know is that bird eggs come in all sizes and colors white eggs like this giant ostrich egg have been around for millions of years over time the eggs just like the birds themselves have adapted to survive some are speckled because they want to blend into their environment so do you see the three eggs in this photo look closer and for blue eggs well the blue color is caused by a pigment in the mother it's the same pigment that makes bruises turn blue and some butterflies like this one have bright blue in their wings pigments also strengthen eggshells so it's actually an active area of research still trying to figure out why birds eggs are blue so the mother lays the bright blue eggs and the parents incubate those eggs it takes about 14 days for them to complete their development in the egg and then they hatch out and then they're going to spend roughly 12 days more in the nest and over that 12-day period they as you saw in your films change enormously they go from a non-flying individual that is completely helpless they're completely blind they have no feathers except for a little down they really look like aliens within 14 days they are out of the nest instead of little bald aliens they look like grumpy old men and within just a few more days they're actually able to fly not like an adult but they can fly so what exactly happens in those two weeks in the nest i don't know if you've ever tried to raise a baby bird but it's it's just so time consuming they just eat and process food all day long watch this dot goose rocco and pepper jack are deep in sleep but when they hear their parents come they shoot right up super fast they eat worms bees caterpillars and flies and they have to eat so much because they have to grow so quickly the selection to grow fast to get out of the nest is probably mostly related to the fact that lots of things eat baby birds therefore it's a dangerous point in their life getting through that quickly is important now if i know one thing about babies it's this they eat they sleep and they poop and it can get very messy but somehow this nest is spotless so where on earth does all the poop go i recorded hours upon hours of footage to figure out exactly where this poop was going because it seemed to just disappear into thin air and then i spotted it turns out the hatchlings definitely poop a whole lot but they were pooping directly into their parents mouth and the parents were eating it uh your your observation that the nest is extremely clean is very accurate and it's because they have those structures referred to as eagle sacks they're basically like baby bird diapers so instead of bird poop making a huge mess the fecal sacs keep it nice and contained i mean it really looks like a disposable thing but the adults as you filmed they'll wait at the rim of the nest for that baby to pick up that fecal sac the moment it emerges from the body now once the parent has the fecal sac they do one of two things if you've got young that are sedentary and they're going to be in one spot for days maybe even weeks you don't want that getting too dirty so sometimes the parents fly away with it to drop it off somewhere else far away from the nest but in many cases the parents ate the fecal sac as i was watching your film he started to get a little sick to my stomach after oh yeah i know birds do this but after a while you watch them do it that many times you oh man isn't that you know let's just throw them all away one of the hypotheses as to why they eat them is that there is useful material in the fecal sex and so it might behoove the parents since they're already working really hard to keep those babies fed to just eat them and capture the energy and water that is still remaining in the fecal sex tasty not all birds do this so this is an osprey nest what they do instead is the babies well when they're really young they probably do poop in the nice little bit but as they get older the youngsters position themselves when they have to go over at the edge of the nest they point their butts out over the edge and then they'll just poop right off the edge of the nest the world is their toilet [Music] after 12 to 14 days growing in the nest hatchlings start to get really crowded here's a moment where goose literally fell out the nest because he barely fit don't worry goose made it back in getting to that point is rough because probably 60 percent of nests fail but this nest it made it the very last piece of footage i captured was this rocco just flew right off the porch of those that do get out of the nest um they're gonna have to make it through to their first year and maybe only about 30 of them actually survive now they've got to begin the important process of reproduction basically in just one year the hatchlings become parents and the process starts all over again what can birds teach us hard work birds are hard working individuals that's for sure they can teach us about ourselves but they can also teach us about the world we live in what they are showing us is how connected the world is birds migrate huge distances and then there are some species which literally call the world the world their home increasingly as time goes on we study them to preserve them and to conserve them so i think they really are showing us that we have to take a large picture view of the world [Music] you

Channel: Vox

Views: 1,200,803

Keywords: robin, fecal sac, bird poop, Nest, hatchling, birding, biology, Birds, baby bird, bird nest, bird poop white, why is bird poop white, backyard bird, birder, education, learning, robin egg, bird egg, hatch, kids, Vox.com, vox, explain, explainer, vox kids, vox for kids, educational video, educational videos for kids, science for kids, science for kids videos, biology for kids, bird watching

Id: lG7OmThrq5g

Length: 9min 43sec (583 seconds)

Published: Wed Sep 02 2020

Reddit Comments

[u/cheezyfloof]

Great video! But also ewww :)

[u/HolyMolyMollyBalls]

This was so great! I have a Robin that makes her best on my porch every single year and I've always had so many questions!