MAHOMET — It's just past 9 on a morning so hot that the sky feels like a hand pressing down. It's already the kind of day on which Mother Nature seems to sink into a lazy stupor.
But there's a flutter of excitement in the purple martin colony at Kevin Rumple's home in rural Mahomet. Today, some of the "teenagers" in the colony, those birds almost ready to leave the nest, will get a new accessory: a small silver band that will help Rumple track his birds' comings and goings each year.
"They're just a personable bird," Rumple says as he watches the martins slice dark paths through the heat-paled sky, trilling a joyful tune. "They love humans."
Rumple's martins live in houses perched high on poles; some in gourd-shaped plastic dwellings, some in larger "condos." He uses a crank to lower the houses to eye level and reaches into each compartment to retrieve the birds.
Meanwhile, Vernon Kleen, a retired avian ecologist with the Illinois Department of Natural Resources, holds a martin in the palm of his hand, its neck tucked between his fingers. He uses a pair of pliers to open a small, beadlike band and fasten it onto the bird's spindly leg.
"I do the left leg," he explains to Rumple, who is carefully transferring more martins from a birdhouse to a tall bucket to await banding. "Other people do the other leg, but it's easier for me to do the left, the way I hold it."
Each tiny band is engraved with a unique number, so that individual birds can be tracked. Kleen explains that purple martins spend the winter in sunny Costa Rica and other points south, and many return to the same colony — or one nearby — in early spring.
It's usually the end of March or the earliest days of April when the martins return, their arrival presaged by a few intrepid scouts flying high above the landscape.
"You can hear them singing up there, as if they're coaxing the influx of birds coming from the south," Rumple says.
Rumple's interest in purple martins started young. His dad came from the western Illinois town of Griggsville, known as the "purple martin capitol of the world," and when Rumple moved to his country home near Mahomet eight years ago, he made it a goal to start his own colony.
He established his colony in 2007, starting out with a grouping of gourd-shaped houses and only one bird. He began playing CDs of "martin music" — called "dawnsong" because it replicates the sounds that the birds make in the early morning — in the hopes of attracting more residents. Five years later, he has well over 100 birds.
Purple martins are named for the dark, iridescent plum shade of their heads and backs. Females have a white-gray belly, while males are purple all over.
This is the first time Rumple has had his birds banded. The idea appealed to him, he said, because it means he'll be able to tell if the same birds return to his colony next spring.
After their winter migration, the banded birds may return to Rumple's colony, or may venture off to start colonies of their own. Even if they don't come home, he'll still be able to get word of their whereabouts from fellow birdwatchers on the purple martin Internet forums he frequents.
In his retirement, Kleen, a Springfield resident, works as a bird bander, tour guide and lecturer on birds of all kinds.
Rumple's martins seem fairly calm about the whole process. Some allow themselves to be moved from house to bucket to Kleen's hand without so much as a twitter of protest.
Others express some doubt about the proceedings, emitting shrill and scraping cries as Kleen scoops them up. Their pointed beaks gape as they strain to escape his curled fingers—but most are quiescent within a few seconds.
Purple martins are known for their amiability. Kleen explains that they're one of several species that adapt well to living side-by-side — elbow-to-wing, if you will — with humans.
This group also includes robins, two of which have built a nest on Rumple's porch, facing the martin colony.
"He thinks he's a martin," Rumple says, referring to that nest's master. "The martins will squawk, and he'll start talking back."
The window of time in which the martins can be banded is fairly small. When they're 13 to 18 days old, their legs are swollen, too large to accommodate the bands. But let them age to 27 or 30 days, and they may find their wings and fly away.
Rumple keeps a close eye on his birds throughout the spring and summer. He does "nest checks" every few days, usually in the early afternoon, and records the number of eggs in each house and the date they hatch in a ledger.
He also watches for the mites that can sometimes infect martin colonies. "That's part of being a good landlord," he says.
Rumple and Kleen have spread out a net in the hopes of catching a few adult martins to band. Halfway through the process, a sparrow becomes entangled and has to be freed — but the adult martins are too canny to be caught. They circle above the colony while Kleen bands their young, as if keeping an eye out.
It takes a little under an hour to band 54 martins. A few houses are empty, meaning that the young who live there have already fledged and joined the adults swooping across the sky.
Afterward, Rumple, his wife, Michelle, and Kleen adjourn to the house for tall glasses of ice water. They watch the birds circle and soar through the dining-room window. This summer's heat and drought haven't fazed them much, Rumple says. They're adaptable. They thrive. They'll spend the warm months grazing on the insects in his pasture before taking off for the sun and sand of Central America.
And they'll return when spring blushes across the croplands of Illinois, their gleaming silver bands letting Rumple know that his tenants have come home.