Before the spider study, Rubi was using a captive colony of blue jays at the University of Minnesota to explore how birds distinguish good prey choices from bad ones such as monarch butterflies.
“Monarchs are toxic, so blue jays that eat them will get very sick. They learn to avoid them,” she said.
Rubi wanted to know whether the birds recognized a toxic insect’s bold colors or its distinctive geometric pattern. She found out that jays used both.
“In the wild, a butterfly’s colors could be hard to see in dim light. Or they could be in the thick foliage where color is more important,” she said. “So having the ability to use both color and pattern is advantageous.”
When Uetz proposed a spider experiment, it wasn’t hard to train the blue jays, Rubi said. The jays quickly learned to peck at different buttons when they either observed a spider or didn’t see one on a video screen.
“Birds are super visual. They have excellent color vision and good visual acuity. It’s not surprising they would have no trouble seeing spiders in motion,” she said.
Rubi now studies genetic evolution at the University of Victoria in British Columbia.