GLENDALE – The early afternoon calm Saturday along the Milwaukee River was shattered by the sound of a rare visitor.

"Kuk, kuk, kukkukkuk, kuk, kuk."

The notes echoed through the hardwoods and across the river, where Peter Thornquist of Glendale was visiting a neighbor.

Thornquist looked in the direction of the raucous call and saw the source.

A bird, which to the uninitiated might have looked like a white chicken, flew across the river to the trunk of a dead tree and roosted vertically, where it proceeded to use its bill to hammer on the bark.

A sinuous dam within the Milwaukee River in Glendale’s Kletzsch Park forms a gentle waterfall. Fly-fishers often wade downstream from it. A bluff with ancient oak trees draws many visitors to three benches and a picnic table. Even on a brisk day last week, a steady parade of pedestrians walked the trail between the river’s west bank and the Milwaukee River Parkway.

This riverfront overlook might soon be erased and replaced.