November 1, 2010 at 9:36 PM CDT - Updated August 23 at 8:04 PM
Every fall, there is a spectacular display that takes place in the sky near the town of Vacherie, La. It seems that fields of tall sugarcane are the perfect roosting spot for tree swallows. Just before dark, the swallows form what look like a giant funnel clouds as they swoop into the cane fields.
The show begins just after sunset. First there are a few birds, then there are more and more and suddenly you see thousands of birds streaming in from every direction, their wings skimming inches above the sugarcane stalks. And as darkness falls, those thousands are transformed into millions.
Andrew Laughlin, a graduate student at Tulane, is researching this natural phenomenon that's been taking place in sugarcane fields near Vacherie for decades.
"It's a safe place for them to hunker down for the night. It protects them from ground predators, from small mammals, it protects them from aerial predators like hawks and falcons and owls," Laughlin said.
He watches as the birds soar into the sky, then this chaotic cloud of swallows swirls into a magical decent.
"Some of the birds will all of a sudden decide they're going down into the cane. And a lot of the birds will start following that. And it creates this sort of funnel, this almost tornado effect of birds funneling down in this ribbon over the can, and into the cane," Laughlin said.
The swallows began roosting in this Vacherie sugarcane field in late October. And they'll return here every night until the sugarcane is harvested.
But after the cane is cut, where do millions of swallow go? Do they stay together or move other nearby fields, or continue their migration to Florida, or Central and South America.
Josh Sylvest grew up near Vacherie and began watching the birds when he was 5-years-old.
"Just the sheer number of birds, it's as impressive as the cane, if all the cane fields were to lift up and the cane was floating over your head and you could appreciate just how much was there," Sylvest explained.
Sylvest is helping Laughlin net a few of the birds. After dark, they work on tagging the swallows and attaching miniature radio transmitters.
"Once the birds are all gone, we're going to drive around listening for their signals at different roosts throughout Louisiana that we can find. And try to figure out, are these birds the same birds we had in Vacherie, Louisiana," Laughlin asked.
At first light, the quiet farmland comes alive with the sound of birds. And without warning, they begin their ascent one twisting formation of swallows is joined by another and another. The mass of birds is so thick it shows up on weather radar as the expanding ring of birds move farther and farther away from the nightly roost. It's a natural wonder, that for a time, is repeated at sunrise and sunset on a magnificent scale.
The farmer who owns the property where most of the swallows are roosting says it may be another few weeks before the sugarcane is cut and the birds move on. It all depends on the weather.
The sugarcane fields are private property, but it's possible to see the birds from River Road or La-3127, which is located to the rear of the cane fields. The birds do seem to target several fields in an area bounded by on the east and west by Chopin Road and Pikes Peak Road, an