|
Hello all,
I'm happy to bring you the second installment about bird migration from Sawyer, our student "guest blogger." She's been reading a book by the Cornell Lab's own Miyoko Chu (see http://www.birds.cornell.edu/AllAboutBirds/studying/migration/sbj).
Bird migration was a major component of the Bird Conservation Conference I just attended; it is a fascinating topic that scientists are anxious to know more about. From a conservation standpoint, I learned that it is important to protect habitats where migrating birds are in the summer (where they breed) and in the winter... as well as along their migration routes! Consider that the warbler you see outside your window in the spring may have just flown in from Costa Rica, Mexico, or Cuba... or that the songbird nesting along the Mississippi River may fly to overwinter on the banks of the Amazon River. To me, it makes the world feel like a smaller place, and the conservation of bird habitat truly becomes a world-wide concern.
By the way, one of my all-time favorite children's books, Flute's Journey by Lynne Cherry, happens to be on migration. I'd encourage you visit http://www.birds.cornell.edu/education/educators/flutesjourney to learn more about the book and find several activity ideas.
And now, onto Sawyer's post!
Best,
Jennifer Fee
Education Program
Cornell Lab of Ornithology
In my last blog, I shared about the fall migration and how songbirds prepare for such a long journey, but I didn’t talk about how they get where they're going. How they migrate across those thousands of miles and back. What scientists have found built into them to help them find their way.
When the birds take off, it appears they use a variety of methods to help them find their way: landmarks, celestial navigation (navigation using the stars), solar navigation, and magnetic fields.
For example, the bobolink (see http://www.allaboutbirds.org/guide/Bobolink/id; photo courtesy by Kelly.Colgan.Azar on birdshare) has been found to have magnetite in its nasal tissue, and so has the white crowned sparrow. This is a really cool discovery! Magnetite is a mineral and is “the most magnetic of all naturally occurring minerals on Earth,” according to Wikipedia (www.en.Wikipedia.org/wiki/Magnetite). Magnetite acts as a compass, telling the birds where they are in relation to the North and South Poles.
However, as they near the Equator (www.astronomy.swin.edu.au/cosmos/E/equator), they are at an equal distance from both magnetic poles and if they only relied on this built in compass, they would become confused and disoriented. That’s why they also rely on the stars, setting sun, and landmarks.
Another way birds can tell where they are is by polarized light patterns.
Polarized light patterns are created when sunlight scatters while going through the atmosphere. Birds can see polarized light, whereas humans don't have that ability. An interesting story is one told by Myoko Chu in Songbird Journeys:
Researcher William Hamilton, III asked a friend in Nebraska to capture and airmail him a bobolink at the University of California, Berkeley, for some tests. Before the tests were finished, however, the bobolink escaped from the lab in Berkeley. The next spring, the bobolink came back to where it had been captured the previous spring, in Nebraska. The bobolink, despite the fact it had left for fall migration from a different area (California), came back to its mating grounds, because it had several different ways to find its way back!
Until next time, happy birding!
-Sawyer
I'm happy to bring you the second installment about bird migration from Sawyer, our student "guest blogger." She's been reading a book by the Cornell Lab's own Miyoko Chu (see http://www.birds.cornell.edu/AllAboutBirds/studying/migration/sbj).
Bird migration was a major component of the Bird Conservation Conference I just attended; it is a fascinating topic that scientists are anxious to know more about. From a conservation standpoint, I learned that it is important to protect habitats where migrating birds are in the summer (where they breed) and in the winter... as well as along their migration routes! Consider that the warbler you see outside your window in the spring may have just flown in from Costa Rica, Mexico, or Cuba... or that the songbird nesting along the Mississippi River may fly to overwinter on the banks of the Amazon River. To me, it makes the world feel like a smaller place, and the conservation of bird habitat truly becomes a world-wide concern.
By the way, one of my all-time favorite children's books, Flute's Journey by Lynne Cherry, happens to be on migration. I'd encourage you visit http://www.birds.cornell.edu/education/educators/flutesjourney to learn more about the book and find several activity ideas.
And now, onto Sawyer's post!
Best,
Jennifer Fee
Education Program
Cornell Lab of Ornithology
In my last blog, I shared about the fall migration and how songbirds prepare for such a long journey, but I didn’t talk about how they get where they're going. How they migrate across those thousands of miles and back. What scientists have found built into them to help them find their way.
When the birds take off, it appears they use a variety of methods to help them find their way: landmarks, celestial navigation (navigation using the stars), solar navigation, and magnetic fields.
For example, the bobolink (see http://www.allaboutbirds.org/guide/Bobolink/id; photo courtesy by Kelly.Colgan.Azar on birdshare) has been found to have magnetite in its nasal tissue, and so has the white crowned sparrow. This is a really cool discovery! Magnetite is a mineral and is “the most magnetic of all naturally occurring minerals on Earth,” according to Wikipedia (www.en.Wikipedia.org/wiki/Magnetite). Magnetite acts as a compass, telling the birds where they are in relation to the North and South Poles.However, as they near the Equator (www.astronomy.swin.edu.au/cosmos/E/equator), they are at an equal distance from both magnetic poles and if they only relied on this built in compass, they would become confused and disoriented. That’s why they also rely on the stars, setting sun, and landmarks.
Polarized light patterns are created when sunlight scatters while going through the atmosphere. Birds can see polarized light, whereas humans don't have that ability. An interesting story is one told by Myoko Chu in Songbird Journeys:
Researcher William Hamilton, III asked a friend in Nebraska to capture and airmail him a bobolink at the University of California, Berkeley, for some tests. Before the tests were finished, however, the bobolink escaped from the lab in Berkeley. The next spring, the bobolink came back to where it had been captured the previous spring, in Nebraska. The bobolink, despite the fact it had left for fall migration from a different area (California), came back to its mating grounds, because it had several different ways to find its way back!
Until next time, happy birding!
-Sawyer
