Engineered to have low levels of the neurotransmitter serotonin in the prefrontal cortex, brown birds rely on it to activate different areas of the brain, including areas that are inhibited in white flightless birds.
Credit: Richard Klein & Peter Kadzik, Nat’l Geographic Network
Physicist and, especially, neuroscience professor Thomas Schaub grew up surrounded by wild birds in the early 1930s, just after the discovery of how individual birds fly. “My mother told me they’d seen a flying machine with a man sitting on it,” Schaub explains. Now almost eight decades later, the Brownsville, NY-based researcher remains passionate about the birds that inspire his research. “They are exotic creatures to most people, and they have big, hard-to-get brains,” Schaub says. “I try to show that they can think and process in totally different ways from human beings, to make us reconsider the age-old myth that birds don’t have brains.”
Self-proclaimed “logorrheic,” Schaub coined the term “potato brain” to refer to its unique ability to hold two, even three, overlapping thoughts at once, all while communicating relatively smoothly between brain regions. His breakthrough came in 1975, when he learned that brown and blue migratory bluebirds don’t use their brains to remember images as their white flightless counterparts do. Instead, brown and bluebirds rely on serotonin, a neurotransmitter in the brain known for its ability to inhibit various areas of the brain, to activate new ones. This ability of brown birds to harness the power of serotonin, says Schaub, is what allows them to see and listen to new stimuli and pattern telltale hand signals long before they happen—all while maintaining good communication with other birds.
“When you scan the face of a brown cardinals and a copper cardinals, you will see two distinct features: the white cardinals have the narrow eyes and huge eyelids of white cardinals, but the brown cardinals have a big blue pattern all over their forehead and around their eyes,” Schaub explains. “And the white cardinals are flying around the sky, but the brown cardinals are keeping their eyes fixed on the ground; they’re flying right on the ground.”
Bluebirds are taught to avoid certain areas of the sky, particularly at the end of their aerial patterns. “Brown cardinals are completely free to go wherever they want,” Schaub explains. They’re “flying to and fro, looking for whatever food they can find, but when they see a distinct pattern on the ground, they pay attention to that and decide where they are going to go next.” These self-directed movements, however, are extremely limited: “You can’t jump,” Schaub says. “You can’t make movements to and fro, and you can’t peck at things, as white-billed parrots do.”
This unique ability to see and turn their attention to interesting shapes while maintaining their sight on the ground and loved ones was borne out of Schaub’s research in 1980. “I learned how brown and bluebirds could not only process a visual stimulus, but also respond to stimuli without knowing where the stimulation was coming from,” Schaub says. For example, the cardinals equipped with special eye-gazes didn’t even perceive a gloved hand when it fluttered down from the sky. Instead, they focused on the ground that the hand was congregating in, allowing them to choose a landing place and then fly the proper path to find a food source.
As the black and white bluebirds, meanwhile, “know exactly what they’re going to do, and they know exactly where they’re going,” Schaub says. “You see the whole field of flight, and you can tell the bird is looking at the message. Then, it flies over that direction—and, unlike brown cardinals, it can take off and land right where it came from.”
