Thousands of purple martins have returned to their late summer roost at the Nebraska Medical Center, again giving people an exquisite view of one of nature's rituals.
Local birding enthusiast Jim Ducey said the numbers are fewer than in past years, but the show is still captivating.
About a dozen spectators gathered at the center earlier this week.
“Amazing,” one ball-cap wearing retiree said as he leaned back in his lawn chair and watched the birds swirl above.
Omaha's purple martin gathering has become a popular draw for people because the birds nest in the same easy-to-access site at 44th and Farnam Streets, follow a reliable schedule and put on an acrobatic show that entertains all ages.
Ducey said the number may continue to swell before dropping off in September.
One reason purple martins are a favorite of birders is their intimate relationship with humans. Because so much of their habitat has disappeared, they depend on constructed purple martin houses for nesting.
In turn, humans wait each spring for the return of purple martins that they hope will mate and raise families in their backyards.
The birds gathering at the Nebraska Medical Center have spent the summer raising broods in martin houses across the region. After leaving Omaha, they'll head to Brazil for the winter.
Purple martins are the largest of the swallow family and grow to about 7.5 inches long. Like other birds, they're exceptionally light, weighing a little less than 2 ounces.
They eat flying insects such as grasshoppers, dragonflies, June bugs, cicadas and butterflies. Contrary to popular belief, they are not major predators of mosquitoes.
Highly social, they live in colonies. Pairs are monogamous, although the males are promiscuous.