Few natural phenomena are as magical and mysterious as bird migrations. I wish I had more than nine minutes, but I’ll give you just a taste of why migrating birds are so cool.
“Marshland Elegy” by Aldo Leopold (PDF from A Sand County Almanac, 1949)
These 5 birds are all winners in the migrations Olympics (National Audubon Society)
Bird migration is one of nature’s great wonders. Here’s how they do it. (National Geographic)
Fabulous flights: 13 amazing facts about bird migration (BBC)
How migrating birds use quantum effects to navigate (Scientific American)
Audubon’s Rowe Sanctuary’s crane cam (livestream)
Sandhill crane sound clip from the National Park Service: https://www.nps.gov/subjects/sound/sounds-sandhill-crane.htm
Music: Jens East — Daybreak (ft. Henk) www.soundcloud.com/jenseast
Licence: Creative Commons Attribution V4.0
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Transcription (remember, this is a direct transcription of what I said and is not actually how I write!):
Welcome to 9 Minutes of Wonder. I’m Betsy Hedberg. I hope this podcast will help you rekindle your sense of wonder for this awe-inspiring world. If you like what you hear in the next few minutes, please subscribe and share.
[sound of many sandhill cranes]
“High horns, low horns, silence, and finally a pandemonium of trumpets, rattles, croaks, and cries that almost shakes the bog with its nearness, but without yet disclosing whence it comes. At last a glint of sun reveals the approach of a great echelon of birds.” Aldo Leopold from “Marshland Elegy” in his famous work, A Sand County Almanac.
That sounded like a lot of birds, right? And it was. That was the sound of thousands of sandhill cranes in Denali National Park in Alaska. But groups of sandhill cranes sound like that everywhere.
I used to go to central Nebraska from my home in Denver every year in March, and I would enjoy seeing the migrating sandhill cranes. They were on their way up to the northern parts of Canada and Alaska.
They spend about four to six weeks along the Platte River in Nebraska. And it used to be along the, like most of the Platte River, but over time the river was developed in a way that it just didn’t work out for the cranes because they need to spend their nights on sandbars that are in the middle of the river. So there are only a few places left where they’ve got those sandbars that will keep them safe during the night from predators.
And then what happens, first thing in the morning, is they start to wake up and they start to get really, really, really loud like you just heard. And then small groups and finally huge waves of the cranes will take off into the air. And it is such a magical sight and a magical sound.
They go into the cornfields that are just next to the river, and they spend the day eating corn. The leftover corn from the farmers’ harvests is one of their favorite foods, or is the main thing that they eat now when they’re in Nebraska.
In the evening, they fly in a very noisy way, and a very spectacular way, back from those cornfields into the river to keep themselves safe all night.
You can go to the Iain Nicolson Audubon Center at Rowe Sanctuary in Kearney, Nebraska if you ever want to see them yourself. They have blinds where you go out with a guide, and then you spend like maybe a couple hours in a blind looking at the cranes. It is just one of the most magnificent things I’ve ever done, and I got to do it a bunch of times.
This isn’t just about, “yeah, yeah, yeah, I’ve been there, done that.” This is an experience that you want to repeat, because bird migrations are really fascinating and they’re really special.
And you get to think about how this has been going on for, gosh, you know, how long, right? Millions of years, even before people ever existed. And it’s just awesome. And we obviously hope that this will continue for many millions more years, regardless of whether people are around.
Everyone is blown away by facts about the longest migrations of birds. For example, the bar-tailed godwit holds the record for the longest nonstop bird migration. They fly from Alaska, which is where they breed, to New Zealand and Australia, and they don’t stop.
The Arctic tern has the longest annual return migration of any species. Some individuals have logged more than 50,000 miles, or 80,000 kilometers, in a single year. And they migrate from one polar region to another and back, spring and fall, spring and fall, over and over again.
And even tiny birds can migrate really long distances. So for example, the calliope hummingbird migrates between the northern Rocky Mountains of North America and Mexico. So they’re migrating over 5,000 miles, or 9,000 kilometers, round trip every year. Little tiny hummingbirds.
A few other little tidbit facts about bird migration are — one that I found really interesting — the ancient Greeks used to think that birds…they wondered where birds went, right? They didn’t really have the full sense of geography down. So where did the birds go when they go away? And they speculated that the birds turned into fish or other birds or even barnacles over the winter and then reformed themselves during the spring and, you know, until they left again and took other shapes in the fall.
Even in the 19th century, Europeans really didn’t have an understanding of where birds left when they flew south. I guess they knew that the birds flew south, but where did they go? In 1822, a stork arrived in Germany with an African spear stuck through its body. And so somebody found the bird and noticed that the spear was from Africa. And that’s when they realized that the birds are really going a long way. They’re going all the way to Africa and coming back.
But for me, it’s not just about what are the coolest long-distance facts or the historical facts. It’s also just thinking like, how do they do it, right? How do they know where to go? And it’s really very interesting. Birds can navigate using the sun and stars and looking down at the landscape below them, which they memorize over multiple journeys, especially their first journey.
But they also, as you may have heard, use the Earth’s magnetic fields to navigate. This is the most mysterious way of all. Scientists have been trying to unravel that for a long time and haven’t completely gotten to the bottom of it either, but they’re getting closer.
Migratory songbirds actually inherit a sense of not only when to migrate, but which direction to go. This is not learned. Many migratory songbirds just seem to know, because although many geese, for example, will follow their parents on their first migration, the songbirds aren’t doing that, and they’re not learning this from their parents.
But songbirds do need to venture out for a first time and learn the best route. Even though they’ve got a lot of innate information that they inherited, they still have to develop the best strategy and most accurate route and learn a precise course by developing a mental map during their first migration. And if they veer too far off course at first, they’re generally not going to learn where to go and they’ll die. They won’t survive their migration. This happens to a lot of birds.
But back to the magnetic fields. How does this work? The Earth’s magnetic fields are apparently at least 10 times and maybe up to 100 times weaker than a magnet you might stick on your refrigerator. Yet still somehow birds are influenced by those magnetic fields. And I found an article that some recent research just within the last few years that is offering some new clues.
I’m just going to read you this quote. It might not make any sense. It hardly made sense to me, but I thought it sounded so cool. This is from a study that was written up in Scientific American, and I will post a link to that page, of course, in the notes.
“Our experimental evidence suggests something extraordinary: a bird’s compass relies on subtle, fundamentally quantum effects in short-lived molecular fragments, known as radical pairs, formed photochemically in its eyes. That is, the creatures appear to be able to “see” Earth’s magnetic field lines and use that information to chart a course between their breeding and wintering grounds.”
So in other words, they have this mysterious sense within their eyes that lets them kind of see the Earth’s magnetic fields.
And then they go on in great detail describing how that might work. But then, you know, at the end of this very scientific, very detailed article, they say this:
“When you next see a small songbird, pause for a moment to consider that it might recently have flown thousands of kilometers, navigating with great skill using a brain weighing no more than a gram. The fact that quantum spin dynamics may have played a crucial part in its journey only compounds the awe and wonder with which we should regard these extraordinary creatures.”
And really, I’m so glad they said that, right? Because this is really all about awe and wonder. I mean, if they have radical pairs and there’s quantum stuff going on in their eyes, it’s so cool. But even if you’re never going to know about that, even 100 years ago or 10 years ago, when people had never heard of that, they could regard bird migrations with awe and wonder. And that’s what really matters for me anyway.
So back to the Sandhill crane migration. I’m going to post some links. One is to this wonderful crane cam. It’s a live stream. And you can look at the Iain Nicolson sanctuary that I mentioned a few minutes ago, and you can see the cranes live.
Enjoy looking at the crane cam, look up in the sky, look around you, notice the birds on their migrations, and notice the birds who have started to sing too, whether or not they’ve migrated to where you live or they’ve been there all winter. I will talk to you again soon.