Author: Dr. Angela Tringali
Researchers at Archbold Biological Station are gathered around a computer screen, watching a video of a bird hop around a doll. The bird is gathering peanuts that have been placed around the doll’s feet. The doll is a troll doll, complete with brightly colored hair and a jeweled belly button. The bird is a Florida Scrub-Jay, a highly social member of the crow family. As the jay gathers the peanuts surrounding the doll’s feet, it hops in a semi-circle from the doll’s rear to its smiling face. Mouth full of peanuts, the jay lifts its head. It finds itself eye to eye with the troll and jumps straight into the air before fluttering backward.
The interns who have recorded the video are laughing, and it is hard not to. We have all been startled by a mannequin or cardboard cutout before and laughed at our own reactions. Dr. Angela Tringali, a researcher in the Avian Ecology program, said that the jay’s reaction was not what they intended. “We are not trying to startle jays; we are trying to measure their response to novel objects. Just like your brain might initially perceive a mannequin caught from the corner of your eye as a person, the jay’s brain is not perceiving the troll doll as a new object, but as a living thing. The startle response is the jay re-categorizing the doll from inanimate to animate. If the jay had flown in from the other direction and seen the doll’s face, it may have decided not to approach at all.” She notes that all the jays they observe are free-living wild birds. “They can choose to approach the object and get a peanut, or not. We aren’t forcing them to participate in our observations.”
Why are researchers trying to measure the bird’s response to novelty in the first place? “Typically, people who study animal behavior measure response to novelty because it reveals how likely an individual animal is to explore its environment and, unlike measuring exploration in the wild, is easy to measure. A bird that seeks out new things may be more exploratory, traveling farther, interacting with more birds and places. They may be bolder, or more proactive. A bird that avoids new things might be very different, instead building long-term associations, but to fewer birds and places. The human equivalent would be someone who traveled the world and has acquaintances on every continent compared to someone who lives in the town they were born in and has had the same set of friends since kindergarten,” explained Dr. Reed Bowman, Director of the Avian Ecology Program. “We are measuring response to novel objects because we think it might tell us about a bird’s willingness to explore novel environments. Maybe a bird scored as more willing to explore a new object will explore more places and disperse farther from the area in which it was reared.”
In order to measure response to novelty, the researchers had to produce objects that the scrub-jays perceive as novel. Based on the reaction to the troll the researchers eliminated it and anything else with a face from the array of potential novel objects. “Animate things have faces, and we want a novel object, something that is inanimate, not something that they jays could perceive as a predator or prey,” said Tringali. “After the troll, we tried a tennis ball and then we started getting creative. We had everyone build an object to use, first using legos then tinker toys. This allowed us to keep the size and color of the objects similar, while varying the shape.” However, the Archbold researchers still weren’t sure the objects in the array were being perceived by the jays as novel, and if they were, that the response to the object would be related to exploration.
“We chose this test, where we present the scrub-jays with a novel object paired with a peanut reward and measure latency to retrieve the reward, because it was supposed to be easier than measuring exploration directly. Instead it turned out to be complicated. We started to think it would be easier to measure exploration in the wild. So we did,” said Tringali. As well as presenting novel objects, the researchers started surveying a grid of points several times a week and recording the scrub-jays they saw. “As a measure of exploratory tendency, we mapped all of the places each bird was seen and then we counted how many different places each bird was detected and measured the farthest distance each bird was observed from home,” Tringali continued.
“These surveys take a lot of effort,” remarked Bowman. “But we hope to reduce the time involved considerably.” Advances in cellular tracking technology are making this wish a reality. This year, graduate student Young Ha Suh began a pilot study using this new technology. She put out a grid of receivers, one every 200 meters, and fitted birds with transponders that send a signal out every two seconds. “The signals are picked up by the receivers, allowing us to determine very precise GPS quality locations of the tagged birds as they move within the grid,” she explained. “Right now, the grid only covers a small portion of Archbold Biological Station, but we plan to expand the grid and fit more birds with transponders.”
Tringali noted, “This new technology allowed us to examine the relationship between exploring novel objects and exploring novel environments. For some birds, response to novel objects did predict exploration, but for others it did not. Soon, instead of observing jays hopping around objects and inferring exploration, we will be watching the them blip across a map. This is a big improvement. By expanding our ability to measure how jays explore, we no longer have to guess what the jays will perceive as novel.” Bowman added, “This technology will enable us to answer questions that previously we could only dream of studying.”