If you’ve ever thought that your mate is a member of another species, you’re not alone.

Ray Pierotti, a Kansas University associate professor of ecology and evolutionary biology, has studied two species of seagulls on the West Coast and found that for female seagulls, a male seagull’s individual characteristics are more important in the search for a mate than whether he’s a member of the same species.

“Basically, female seagulls are fed by males, and when she’s trying to be fed by a male, she’s going to look for two things: the quality of the territory he holds and the quality of the food he brings to her,” he said.

“If a male who is a member of another species is doing a good job of that, she is probably going to be inclined to pair with him, regardless of whether he’s a member of her species.”

Pierotti’s research will be featured Monday as part of a series of Darwin Day events on the KU campus. Starting at 6 p.m., Pierotti and nine other KU researchers will be giving presentations at the Natural History Museum about their work.

Pierotti said in one of the areas where he’s done research, a hybrid species – a combination of the Western gull and the Glaucous-winged gull – outnumbers the nonhybrids. Environmental factors play a role in mate selection, he said, because bald eagles increasingly have turned to preying on gulls with the decline of salmon fisheries in the region.

“What we’ve shown pretty consistently is that here we have two good, separate species that are now breeding together because the environment’s changed,” he said.

All this news might be a shock, he said, to people who think that species don’t evolve – that once a species is created, it never changes.

“If they understood it, they would probably be bothered by it,” he said.