How does the Canada Goose know where to migrate?

At 3:27:11 on the afternoon of January 15, 2009, United Airlines pilot Captain Chesley B. Sullenburger sucked an entire flock of Canadian geese through the twin turbofan engines of his Airbus A320. The geese instantly suffocated the airplane’s engines and induced an unpowered descent towards the sunlit rooftops of New York City.

Sullenberger, an experienced pilot with more than 20,000 flight-hours under his belt, quickly took the necessary actions to execute a graceful emergency landing into the Hudson River. The quick thinking of Sullenberger and crew saved all 155 people aboard US1549, including a passenger in a wheelchair; Sullenberger has since been recognized for directing the most successful emergency landing in aviation history.

Soaring nearly a kilometre above New York, the unfortunate flock of Canadian geese that disrupted flight UA1549 was likely in the middle of the arduous pilgrimage that many North American species of birds must undertake come wintertime: seasonal migration.

 

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Mass avian migration is the annual movement of birds between breeding (summer) and non-breeding (winter) habitats. More than HALF of all the bird species in North America migrate south every year!

The Canada Goose commits to a particularly long voyage, with some flocks traveling from the high arctic regions of Northern Canada to southern Mexico. The distinctive flying-V formation is a common site in autumn and springs skies when geese and other migratory species set out in search of warm climates, rich food sources, and (presumably) fishbowl margaritas.

Staring at those majestic, honking geese soaring so high above, I always wondered how they knew where to go every year. If you were to dump me and the average flock number of my similarly useless friends (57.4) in the Arctic, we would have no idea how to get from Canadian tundra to Mexican desert and WE HAVE iPHONES. Also, geese’s brains are literally the size of walnuts. How DO they know where to go?

4 ways geese navigate to warmer climes:

The complexity of navigating thousands of kilometres to the exact same location every year is staggering. We’re still not 100% sure exactly how geese make this incredible journey, and their methods continue to be studied.

Here’s what we know about how geese find their summer homes:

  1. Sun-based navigation: believe it or not, geese and other migratory species are able to track their route using the position of the sun. The solar compass method works only moderately well because the sun is constantly moving throughout the day and completely absent at night. Also, clouds.
  2. Landmarks: all along their thousands-kilometre flight, geese are constantly scrivening landmarks to their tiny walnut brains. There is evidence that geese and other birds assemble mental maps of their journeys, which they recall in future years to help them get to their destination
  3. Olfactory navigation: geese can literally ‘follow their nose’ during a migration to help them find their breeding grounds.
  4. By far the coolest navigation method, ‘magnetoception’: goose brains and beaks contain small deposits of magnetite, an iron-containing biomolecule. This compound allows geese (and many other birds) to sense the magnitude, polarity, and direction of Earth’s magnetic field and orient their route accordingly. Fascinatingly, scientists have also mapped a neural connection between bird eyes and the part of the forebrain that is magnetically active during migrational orientation, meaning that birds quite possibly SEE the Earth’s gravitational field. WHOA.

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What’s most impressive to me is that all of the above methods only provide geese the same analytical tool that a Girl Scout might have if she were asked to migrate 3000km from the Northwest Territories to Mexico City: a compass. Birds still don’t know how whether to stop or keep going at any given point, or how to account for being buffeted off course by wind (although old birds do seem to be better at course-correction than young birds).

So there you have it- geese are pretty impressive. As a Canadian and an amateur biologist, I feel it’s my obligation to elucidate more about the Canada goose, other than to point out that they make a poor source of jet fuel. Though they are cantankerous and unsanitary, and though they often swoop locust-like into our parks and beaches to defecate with a dedicated fervor, geese are intelligent and capable animals and we should be proud to call them our national bird.

Fin

 

Links or it didn’t happen:

http://nationalgeographic.org/media/how-do-birds-navigate/

https://prezi.com/h9-0jkix_a7c/copy-of-navigation-of-canadian-geese/

http://www.wbu.com/chipperwoods/photos/geese.htm

http://link.springer.com/article/10.1007%2Fs00359-005-0627-7

 

 

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