I’m reading a book about migration – Living on the Wind, Across the Hemisphere with Migratory Birds by Scott Weidensaul. I don’t think we realize what an absolutely incredible feat birds perform twice a year.
Take the bar-tailed godwit for example. Never seen, let alone heard of a bar-tailed godwit? Me neither, but that’s ok. What’s important is this birds’ astounding migration.
I haven’t seen one because their nesting grounds are eastern Siberia and western Alaska, two places I’ve never been.
These birds vacate their breeding grounds in mid-July and amass along the peninsula of Alaska for a few weeks, chowing down on clams they find in the mud zone. All that food results in an increase of their body weight by 55%, creating thick layers of fat. At the end of this food orgy, the birds’ internal organs change. Because those fat layers will be used as migration fuel, the birds don’t really need their kidneys, liver and intestines until they reach their wintering grounds. So those organs shrink and atrophy.
With layers of fat and shrunken internal organs, the flock is ready. Ready for the wind to take them south over the open Pacific Ocean.
Where do they go, these 16″ tall birds that weigh less than a large cup of coffee?
That’s right. New Zealand. 6,800 MILES from that all you can eat clam bar of western Alaska.
And they fly non-stop until they find that California-sized island in the largest ocean in the world, taking four or five days at 45 miles per hour to do so. They can’t stop and rest, because unlike some ocean migrators, they’ll drown if they land on the water.
How do these birds actually do it? How can they fly non-stop for five days? This just boggles my mind. They don’t go into training before their flight, working up to being conditioned to travel nearly 7,000 miles all at once. I am amazed their muscles are capable of such sustained effort.
Even someone who routinely runs a half-marathon has to train and condition themselves before they set to and run a full marathon.
This to me is just the most incredible thing in the natural world. I’ll be reading more about migration and working on developing a migration unit for homeschoolers. Because this is just too cool to not investigate further.