The Tree Swallow

Birds of a feather flock together, as the saying goes. Tree Swallows must have read the same book because they form huge flocks in late fall and early winter, sometimes numbering into the millions. During the day Tree Swallows can be seen everywhere, gliding and turning effortlessly in the sky. But they prefer to roost near water, ensuring themselves a ready supply of insects. At dusk the sky fills with the swallows and they start swirling in a circular motion until they form a funnel into their roost. 

I had heard about the Tree Swallow tornadoes but never witnessed one; and since the tornadoes occur every year in Louisiana, I put seeing a tornado at the top of my bucket list. Somehow the regularity of these tornadoes didn’t ensure that seeing one would be easy. Louisiana has parishes full of sugar cane fields, so I needed to find which areas were the most attractive to the swallows. It took me a few years to finally land in the right place at the right time.

A birding contact in the Vacherie area promised to let me know when a tornado occurred, and birding friends advised that the period between October and December was the prime time for finding large roosting sites and explained that the premier cane fields could be found around Vacherie, Louisiana. The trick was to get to the roost before the cane got harvested and the roost relocated.

I received a credible report, but postponed the fieldtrip until the weekend because I was busy at work. I wanted the swallow tornado to be on the same schedule as me. This inevitably resulted in finding the fields harvested and no tornado. After three failed attemtps, I was getting frustrated and knew I would have to stay ‘on call’ when the next report came in.

That call came, and I quickly made plans to leave work early the next day. On a Thursday afternoon two birding friends drove with me to the levee in Vacherie. We were not disappointed.

We waited around the levee for about thirty minutes while the sun was setting. The cane field was across the highway and our perch on top of the levee gave us a great view of the field. It wasn’t quite dusk yet, but I couldn’t find the swallows. Had the roost changed location? Finally, my friend Joe told me to look up. Of course I had been looking up, but just not high enough. I raised my gaze a few more degrees and saw millions of swallows. How had I missed them all?! I turned around and looked east and west, and the swallows were in every field of view. And they were flying lower quickly. It was like being in a galaxy of moving, swirling black stars. As I continued to watch, without binoculars now, I noticed the swirling was becoming more concentrated and resembled a black cloud.

A couple of cars and other folks had joined us on the levee. They didn’t have binoculars and weren’t bird watchers, but they too wanted to see the swallow phenomenon. My birding friend Jeff, who is an entomologist, was counting birds; he estimated the population at around five million.

As the birds descended, they also seemed to stream over toward the cane field. Suddenly, the flowing stream of birds swirled into a tight, circling mass, then dove almost straight down into the cane field. Within a few minutes, they were gone, tucked in safely among the cane leaves for the night.

Wow! I would have sworn it was a tornado in the mid-west, the kind one sees on the nightly news.

If it’s not possible to witness a tornado, you can find Tree Swallows picking insects off of water. They can be seen gracefully skimming the tops of lakes and ponds. They bathe by flying low over the water and skimming their bodies against the surface, then rising quickly while shaking off droplets.

Videographer: Bob Loudon

Description: Tree Swallows are small songbirds with very short, flat bills; long, pointed wings; and a notched tail. Males are iridescent blue-green on their backs with black flight feathers and bright white necks and chests; females are duller with more brown.

When: They winter in coastal Louisiana; found throughout Louisiana during migration

Breeding: They breed in tree cavities made by wood-peckers, hollow stumps, or human built nest boxes.

Feeding:  They eat on the wing, sometimes converging on insect swarms. Eat mainly insects, but some plant matter. During the breeding season their diet can contain high-calcium foods such as gull eggs, clamshells, and fish bones.

Interesting facts: The female does most of the nest building; nests usually consist of grasses and pine needles, though cellophane and cigarette filters have been used. She presses her body against the nest material to shape it into a cup and lines it with many feathers of other bird species. Tree Swallows like to display and play with the feathers during the early nesting season.