Spring Migration

One of the most astonishing phenomena in nature is occurring this week across much of the United States, but since it happens largely after dark most people aren't very much aware of the amazing spectacle that's occurring in the skies above them most nights at this time of year.

I'm referring to the movement of millions of birds from their winter haunts in Central and South America to their breeding territories in North America. The migration involves birds of all types, hundreds of different species, navigating their way north to find a mate, establish a territory, breed and return south again in the Fall.

To help give a sense of the movements of birds during migration, the Cornell Laboratory of Ornithology has produced a fascinating animated feature that shows the annual migration pattern of 118 different North American species. The migration animation can be viewed here.

There's also a link on the page which takes you to a similar animation which shows the particular species of bird that's being represented. If you love nature you're sure to enjoy this.

Here are a few questions to ponder while you're watching: How did migration, not just in birds but also in butterflies, fish, turtles, whales, dragonflies and numerous other creatures, ever evolve through random mutation and natural selection? How do these animals know how to navigate their way back and forth, often returning to the exact patch of territory they departed from six months before? How do the young of the year, which have never made the trip before, know how to do it?

It truly is a marvel.

Cape May Warbler