Central Texans hold dear their winged insect eaters. They worship and protect Mexican free-tailed bats. They build gourdlike hotels for purple martins. They name cafes after nighthawks.

And any concrete bridge over a Texas creek now attracts a merry mob of cherished cliff swallows or barn swallows.

But what about the chimney swifts?

These gray-brown, short-tailed dive bombers were once common east of the Mississippi River. They moved westward with civilization, since the brick or stone towers above settlers' fireplaces nicely resembled their natural nesting spots in hollow tree trunks.

But then humans turned on the dainty swifts. They smoked out chicks, cleared out nests, screening chimneys or employing metal tubes that were of no use to the birds. One study showed that the North American population of the hardy migrants who winter in South America had declined by more than 50 percent from 1966 to 1991.

To the rescue came an unlikely pair of Austinites — Paul and Georgean Kyle, who own Rootin' Ridge Toymakers in the 26 Doors center. Back in the 1970s, these do-it-yourselfers built a house above a remote ravine that drained into Lake Austin. Now Apache Shores is hemmed in by upscale development. Yet the land here retains the informal feel of a old-school vacation community.

The Kyles' home now sits amid a 15-acre bird sanctuary with towers that became crucial to the survival of the species.

Back when they camped out at their unfinished home, the Kyles were enchanted by the wildlife that wandered onto their property. They quickly enrolled in courses to learn how to rehabilitate lost, orphaned or injured birds and mammals.

In 1983, the Kyles met their first chimney swift at the Travis County Humane Society.

"The volunteer handed us a shoebox," they recall in their book, "Chimney Swifts: America's Mysterious Birds above the Fireplace." "And we carefully slid the top partially to the side. Instead of seeing the flurry of feathers, feet and bill that we had come to expect from wild birds, we were confronted with the most remarkable eyes we'd ever seen. When we carefully reached inside the box, the bird did not struggle. Instead, it willingly climbed on, clung tightly, gazed directly into our eyes for a few moments, then wearily closed its lids and resigned itself to whatever fate was to come."

With expert guides, the Kyles learned how to hand-rear baby swifts. They earned a grant to research their discovery that an adult swift's saliva might be essential to a chick's growth. After raising more than 1,500 swifts, they established the North American Chimney Swift Nest Site Research Project in 1995, which spread data and excitement about swift rehabilitation across the continent.

"They pretty much brought the species back," says Nancy Manning, executive director of Travis Audubon, the area's chief bird advocacy group.

Turns out they had a predecessor in Iowan Althea Sherman, who studied the swifts' home life close at hand. In 1915 she built a "houseless chimney," a hollow tower with observation windows that the birds quickly adopted for nesting.

Like Sherman, the Kyles spent years observing everything about swifts once the birds reached Texas in March on their return north. They documented the signposts in the lives of the swifts, including their complicated, elegant flight patterns.

They also built towers. A lot of them. By 1989, they were turning their property into a swift preserve, calling it Chaetura (pronounced "Kay-too-rah") Canyon after the swift's Latin designation: Chaetura pelagica.

They experimented with materials like concrete and cinder block. For one model, they were inspired by a old cistern in Jonestown that had attracted a healthy swift population. (The town holds a SwiftFest every fall before the birds head south.)

The Kyles have encouraged swift habitats in any new or old construction that includes towerlike forms. In June, I stumbled on a Kyle swift houseless chimney at the Linnaeus Arboretum in St. Peter, Minn. I recognized it from a distance after attending a lively Travis Audubon benefit at the 15-acre Chaetura Canyon in May.

Though I spied plenty of swifts — 150 species of birds have been spotted here — the Kyles insist that I missed the real show — flight. I will return for that treat.

"The opportunities to provide habitat for the adaptable chimney swift are limited only by our imagination and initiative," the Kyles added in their book. "The skies would indeed by empty without the merry sounds and astonishing acrobatics of the chimney swifts."