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Not only can storks smell, but white storks will show up to a field if they smell cut grass... and storks aren't herbivores.

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For more than a century, many biologists thought that birds couldn’t smell or, at least, couldn’t smell well enough for it to be a useful sense. This idea got started in the 1820s, when naturalist John James Audubon did an experiment that supposedly proved that vultures hunted by sight, not by scent. And then it just kinda stuck around. People pointed to the fact that birds don’t have a real nose and that the part of their brains that deals with smells tends to be small as evidence. But this all sounds wild to me. Like, I get that some animals can smell better than others can, but why would an entire branch of the tree of life just not be able to smell at all? Now we know that this idea was really, really wrong, for a bunch of different kinds of birds, including the vultures of the Americas.  So take that, Audubon! And it makes perfect sense that birds that eat things like dead animals would be able to smell them, but birds smelling things that aren’t food, now that feels a little more bizarre.

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 If we’re going to talk about birds that can smell, we need to talk about storks. There are around 20 species of storks, and they live on every continent except Antarctica. And they can be hard to tell apart from cranes and herons. Look. Stork, heron, crane. Crane. Stork. Stork. Heron. Stork, stork, stork. They’re also not all just the big, white, baby-delivering birds of storybooks. Though, to be fair, they are relatively big birds. The smallest confirmed species, Abdim’s stork, can still be over 60 centimeters tall. But it’s dwarfed by the marabou stork, which can be 1.5 meters tall, and is basically the stork version of a vulture, with its naked head and diet of dead things. And that is not the only stork that has shed its gentle image either. The greater adjutant, known in India by a name that translates to “bone-swallower,” also does not look like it should be trusted with a baby. So then why do we associate storks with babies at all? Well, it might have to do with some of their behaviors, and with some of our own.

The explanation goes like this: over 600 years ago,  people living in northern Europe often got married around the summer solstice, a time of year that was linked to fertility. It was also the time when white storks would migrate from Europe to Africa. And then they’d come back in the spring to have their chicks, nine months later, right around the time a lot of those summer solstice babies would be born. So, people started to associate babies with the return of the storks. They also build large nests in places close to where people live, making it easy for us to see their parenting skills. And that’s not the only time we’ve had questions about what’s going on with European white storks. They’re apparently a pretty common sight at freshly-mowed fields in Germany, the cut grass makes it easier for them to spot their insect and rodent prey. They show up in these fields so often that an elementary schooler at an outreach program in a German town asked one of the scientists there how storks know to show up when farmers cut their grass.

And that got him thinking about how to set up an experiment where he could figure out which sense the storks were using to find these fields. And in June of 2021 (coincidentally right around the summer solstice) that scientist and his colleagues published a partial answer to the student’s question. What the team ended up doing was observing a flock of about 70 storks from a plane on sunny days in the spring and early summer when mowing could potentially take place. When a farmer would start to mow, the researchers would note where all the storks were, if they were within eyeshot or earshot of the field, how many storks approached the field and what direction they came from. Afterwards, they double-checked from the ground whether the birds could see or hear the field or farm equipment and excluded any birds from their data that were too close. Along with their observations, they did two experiments. In the first one, they had farmers cut a truckload of grass in one field, and then drive it to within 2.5 kilometers of where some storks were hanging out and dump it on a field there. In the second one, they sprayed a mix of the chemicals that plants emit when they’re damaged onto uncut fields. And they watched from the plane again to see whether the storks would appear and from where. Turns out, only storks that were downwind of all three kinds of fields (regular mowed, cut and dumped, and chemical treated) would show up. So the researchers are pretty confident that   the white storks are locating these fields by smell alone, and it’s not even the smell of their food itself!

 Which is very weird and I have questions! Like, how do the storks know to associate the smell of cut grass with more easily available prey? When did it start? And are the stork parents teaching this to their stork babies?? Unfortunately, we don’t have any answers to those questions yet. This study just came out and it’ll take more research to figure out exactly what’s going on. But what’s really cool to me is that we started out with the idea that birds couldn’t smell. And if that had been true, it would have been really strange. But what we’re starting to find out almost 200 years later, is that, actually, the truth is even stranger. Not only can birds smell, but they can use that sense in ways that are much more bizarre than we ever even imagined.

 The Bizarre Beasts pin club subscription window is open from now until the end of November 7th! And the stork pins are SO GOOD. You can sign up today and you’ll get the stork pin in the middle of the month and the pins after that around the time each new video is uploaded. And other very exciting news, we have some new products! Bizarre Beasts socks as well as a limited run of a 3D printed kakapo figurine are available on right now! It’s so cute! Look at him! I can’t believe we made this! Follow us on Twitter @BizarreBeasts, and on Instagram and Facebook @BizarreBeastsShow,   for more stork facts! And, as always, profits from the pin club and all our other products go to support our community’s efforts to decrease maternal mortality in Sierra Leone.

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