Tree swallows nest and fly in the Piney Woods
By Jay V. Huner
Swallows are small, dynamic aerial acrobats. One impressive species is the Tree Swallow.
Adult males are metallic blue-green above and snow white below. They have blackish flight feathers and have thin, black eye masks. Females are duller with more brown in their upper parts. Juveniles are brown above and may, with some females, have weak, blurry, gray-brown breast bands.
But, for the most part, the Tree Swallow is so white from bill to base of tail that an old common name is "white-bellied swallow". The name fits! Swallows are hard to follow in the air as they dart about chasing flying insects. Tree Swallows can be picked out in poor light by long pointed wings and short, squared or slightly notched tails.
Barn Swallows, in contrast, have long forked tails.
Most breeding is far to the north of our southern piney woods reaching the arctic in Canada and Alaska. However, some do nest in our region. Unlike Barn, Cliff, and Cave swallows, Tree Swallows are cavity nesters using natural tree cavities, abandoned woodpecker cavities, nooks in structures like bridges, and bird houses! I have personally found Tree Swallows nesting in cavities in snags in Cotile Lake in central Louisiana. This was no accident. Others have found small numbers nesting in similar situations in Louisiana.
I also once saw what appeared to be a martin house in north central Alaska populated by a Tree Swallow colony. So, these birds are pretty flexible in terms of distribution and nest sites.
Unlike other swallows, Tree Swallows do eat berries, especially bay berries. They feed on these in fall and winter seasons. This permits many of them to remain in areas into winter where insects are in short supply in the southern United States into the winter unlike other swallow species that winter in warmer climes. However, good numbers do spend the winter in Cuba, Mexico and Central America.
Tracking devices show that Tree Swallows move around a good bit in fall and winter. They don't hesitate to fly over water and can move from wintering areas in Florida and Louisiana south across the Gulf of Mexico. Such movements are more extensive when winters are especially cold.
Tree Swallows, in migration, form huge flocks, sometimes numbering in the low millions. They generate what is called "swallow tornados" when they go to roost sites at sunset. These swallow tornados are regularly seen from October into November in unharvested sugar cane fields in the St. James Parish area on either side of the Sunshine Bridge near Donaldsonville, Louisiana.
In the Northeastern USA, Tree Swallow concentrations can be so great in fall migration that there are swallow cruises on the Connecticut River so people can experience the phenomenon.
Most people familiar with swallows think of the birds as flying far above the surface in pursuit of aerial prey. However, Tree Swallows will forage for insects in vegetation at knee level and even on the ground unlike other swallow species. I've seen them happily feeding on mosquitos in dense grass on the dam at Kincaid Reservoir in Rapides Parish, Louisiana.