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Date: February 1, 2010

Title: Migration by Celestial Navigation

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Podcaster: Wild Ideas

Organization: Wild Ideas…the Podcast, produced by The Wilderness Center – http://www.wildernesscenter.org

Description: Wild Ideas…the Podcast is a nature podcast. We’d like to share some of the many connections between astronomy and animal species in the natural world. One of the things that comes up often is the breadth of species that use astronomical clues in their migration.

Bio: Wild Ideas…the Podcast is your own nature talk! Our observations of everyday nature events lead to bigger ideas about the natural world. Join general naturalist Gordon Maupin, science educator Joann Ballbach, and conservation biologist Gary Popotnik for a friendly, science-based nature chat. But we don’t want to keep you inside! Listen to Wild Ideas…the Podcast to help you go outside, observe, and play—it’s good for you, good for your kids, and good for nature. Wild Ideas…the Podcast is produced by The Wilderness Center, a nonprofit nature center, land conservancy, and ecopreneurial organization in Northeastern Ohio.

Today’s sponsors: This episode of “365 Days of Astronomy” is sponsored by Don Hoverson, not because I think our species will one day reach those distant stars, but because I hope we will.

Also sponsored by Kylie Sturgess of the Token Skeptic podcast, investigating superstitions and the science behind them at www.tokenskeptic.org.

Transcript:

Wild Ideas…the Podcast for 365 Days of Astronomy

Intro music

Gordon Maupin, Naturalist
I’m Gordon Maupin, a naturalist with Wild Ideas…the Podcast and with me today is science educator Joann Ballbach

Joann Ballbach, Science Educator
Hi!

Gordon
And conservation biologist Gary Popotnik

Gary Popotnik. Conservation Biologist
Hi, everyone!

Gordon
We’d like to share the many connections between astronomy and animal species in the natural world and one of the things that comes up often is the breadth of species out there that use astronomical clues in their migration.

Joann
They actually use celestial navigation, way before people invented it. So, what are some of these, Gordon? Gary?

Gordon
Well, a really interesting experiment was done with Indigo Buntings, where they brought the birds into a planetarium and the birds could wee the “stars” in the planetarium (quotes around those stars) and the birds, when they were ready to migrate northward, would orient to the North Star. And so

Joann
Now, the real North Star or the North Star in the planetarium?

Gordon
The North Star in the planetarium, so they’re obviously looking at it. So then, they decided to play a trick on the birds and they switched the planetarium star ball around so that Betelgeuse was the polar star that didn’t move and the other stars revolved around Betelgeuse instead and the birds oriented then towards Betelgeuse.
Joann
So that’s interesting.

Gordon
So the clue they were using was the stars and constellations turning in a circle around a certain star—the North Star in the wild and, if you trick them in the planetarium, Betelgeuse, I guess.

Joann
So precession doesn’t throw them off at all!

Gordon
It doesn’t throw them off at all. They’re looking at that rotation. But that’s only touching the surface about how wildlife uses celestial clues to migration. Gary, have you got something?

Gary
Yeah, in fact, along those same lines, there, someone else was doing the same type of experiment. They were actually blocking out different constellations as time went on and they found birds were more confused. So it certainly points to birds being able to recognize patterns of stars in the sky.

Joann
But I think it’s different for each species.

Gary
It certainly is, yeah. There’s a number of species who do what’s known as vector navigation, where they know exactly what line they’re supposed to fly and what direction they’re supposed to fly and there’s been some interesting research that’s been conducted with ah with crows in Europe in which they actually moved crows 600 kilometers to the west and then released them and, in spring migration, they flew north and ended up 600 kilometers west of where they normally breed. So, some of them are using vector navigation where others are using celestial navigation.

Gordon
Well, what’s interesting, a lot of animals use solar navigation and that has to be, since they don’t have a calculator to pull out and run their trig functions, they actually have to connect their biological clock with their navigation.

Joann
Now, I always hear of honeybees. What others?

Gordon
Well, honeybees

Joann
Honeybees are a good example

Gordon
At the insect level. There have been experiments. Even salamanders using celestial navigation.

Joann
Salamanders?!

Gordon
Salamanders.

Joann
You wouldn’t even think salamanders could see the sky.

Gordon
You would think, yeah, but salamanders using celestial, using the stars, to find their way around their home range. Pretty amazing stuff! And of course, these animals that are using astronomical clues to navigation, that’s only part of the story because many of these animals use many, many other really cool, subtle, not-fully-understood methods for doing navigation, so

Gary
Yeah, there certainly is geomagnetic orientation

Gordon
Geomagnetic

Gary
That birds are using in that

Joann
Not just birds! I think that…

Gary
Not just birds. Birds get a lot of work done on them. Some of the research is, actually says that it’s associated with sensory receptors that have a, uh, magnetite in their brains. There are some that are now saying at least an alternate hypothesis is that, uh, the response is to a visual pigment that can actually see electromagnetic energy. Kind of like bees can see in the ultraviolet, which is pretty far out there.

Gordon
That’s pretty far out there, but there’s also some working on the hypothesis that some animals, particularly birds, can respond to very, very low frequency sound waves that carry for hundreds and hundreds of miles and will fly their migration route while listening to ocean waves crashing on the shoreline.

Joann
But wait! The great migration patterns are pretty much, well, there’s one right down the Mississippi. And they’re still hearing the ocean shoreline?

Gordon
Uh, perhaps. I think that’s still out there as a bit of a hypothesis.

Gary
Well, and they’re also using the landscape itself as a cue. A lot of research has been done where they’re actually following large flocks of birds with winds coming in either from the east or the west as they’re doing their southward migration and the birds are actually staying on course because they’re using, say, a river as a visual cue.

Gordon
They have to ultimately use visual cues because it’s not at all uncommon for a bird to fly to South America and land in the very same tree it landed in last year and then fly back to North America and land in the very same tree that it was in in North America a year later, so obviously the birds are using a lot of subtle combinations of things, but certainly astronomical cues are very important for many species in their migrations.

Joann
And many species just finding around. You talked about the bees using the sun.

Gordon
The bees use the sun and they communicate that with their dance that people have figured out. The angle of the dance on the comb tells a sun angle and then the length of the dance tells the distance.

Gary
So, what we’re seeing are multiple ways that a number of animal species use to migrate. It’s actually been thought of for many years now that migratory behavior has evolved independently with many, many different species and therefore, a lot of these species have used or depended upon one or more of these ways of navigating.

Gordon
And many species probably use a combination of the various ways.

Joann
We talked about them using the sun, the stars, and the geomagnetic field of the Earth

Gordon
And their memories.

Joann
Yes.

music

Gordon
Wild Ideas…the Podcast is on the same page in iTunes under Natural Sciences as 365 Days of Astronomy. Thanks for having us! You can find The Wilderness Center and Wild Ideas…the Podcast on the web at wildernesscenter.org.

music

End of podcast:

365 Days of Astronomy
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