The tiny birds announce their presence with their high-pitched, staccato chirps.
Their wings, flapping about 60 beats a second, produce the light, saberlike drone that gives the hummingbirds their name.
For some, the sight of a hummingbird is a prized, fleeting moment.
That used to be the way it was for Connie Robertson. Until this year.
The past couple of weeks, Robertson's backyard southwest of Lawrence has been filled with the tiny, green birds.
At any one time, there might be 20 swarming around her three hanging feeders. She figures there are probably 40 or more around her house.
"They must be liking something here," Robertson says. "This has just been incredible."
Mark Robbins, a KU professor and bird expert, says Robertson has the perfect scenario to attract hummingbirds - multiple feeders with sugar water, and trees nearby. They're often initially attracted to an area by certain plants, especially salvia.
Robbins says this is a peak migration period for hummingbirds, most of which are the ruby-throated variety in this part of the state. They're on their way to Mexico and Central America.
"They're fascinating little creatures," he says.
Robertson, a retired employee of the city of Lawrence, feels the same way. She can spend hours at her dining room table, watching the birds.
They dart toward the feeder, hover in mid-air, land on it, eat and go back to the nearby woods, only to repeat the process.
"You're sitting there, reading the paper and watching hummingbirds," Robertson says. "My boyfriend said, 'Boy, we're into cheap entertainment, aren't we?'"
Recently, Robertson decided to fill up a small dish with the sugar water and hold it out in her hand. Several birds approached her and danced in the air a few inches from her hand.
"Then," she says, "one got brave enough to land, and it was just awesome. They're not afraid."
Robertson has lived at this house for two years. She's had a few hummingbirds in the past, but never anything like this.
She's planning to hang up even more of the feeders in the spring. She's just hoping the hummingbirds remember where they spent this fall and decide to come back.
"I've never seen anything like this," she says. "They're so little and cute."
Facts about ruby-throated hummingbirds
Size: Adult hummingbirds are about 8.5 centimeters in length and weigh 3 to 4 grams, which is less than a nickel. They may nearly double their weight prior to migration.
Wings: They flap their wings 60 to 80 times a second and can fly about 25 miles per hour.
Pitter-patter: Their hearts beat 250 times per minute while at rest and 1,220 times per minute while flying.
Home sweet home: Hummingbirds make their nest from spider webs and plant materials.
Babies: Chicks are about 2 1/2 centimeters long when they hatch. They then double in size each day for the first few days of their lives.
Short lives: Most hummingbirds die within their first year. Those that don't have an average lifespan of about three years.
Supper time: The birds eat their weight in nectar or sugar water each day.
Source: Operation Ruby Throat, www.rubythroat.org