Bob Motz has seen lots of amazing wildlife in a lifetime of observing nature — giant tortoises on the Galapagos Islands, millions of monarch butterflies in the mountains of Mexico and lions in Tanzania, Africa.

But he experienced a “first” last month, right outside the windows of his Rock Island home: a cardinal that is half-male, half-female, he says. The bird’s male side is bright red and the female side is a buff brown.

This anomaly occurred during cell division in the bird’s early embryonic stage when the sex chromosomes did not separate properly to the cells, explains Motz, who taught biology at Rock Island High School for 36 years.

The result is what’s called a “gynandromorph,” a creature with half-male, half-female characteristics.

Motz has never seen anything like it and neither have other Quad-City area bird watchers/experts.

“It’s very unusual,” says Kelly McKay, a Hampton, Ill., field biologist and Quad-City bird expert. “I’ve never seen it.”

“It’s a real mix-up of nature,” adds Mary Lou Petersen, another birder and longtime member of the Quad-City Audubon Society.

It is not unheard of, though. Motz has a photo of a gynandromorphy butterfly that he uses in the genetics class he teaches in the College for Kids program at Black Hawk College. These creatures typically are sterile and cannot reproduce, he says.

The unusual cardinal was first spotted in December when Motz and two friends — Jim Frink and his wife, Betty — were sitting around his dining room table. “Jim was facing the window and he saw it first,” Motz recalls. ” ‘He said, ‘Bob, quick, look!’”

The bird was in a hawthorn tree, eating some of its fruit, and has continued to hang around since then, Motz adds.

Alma Gaul can be contacted at (563) 383-2324 or agaul@qctimes.com.