Scientists are trying to understand the causes of petty squabbles between captive parakeets, and are finding that sex does not seem to play a major role in them.

“You fight all day, but they are minor fights. Constant, harmless squabbling…Both females and males fight each other, which is fascinating. It’s a constant fighting game.” Yuchen Chen explains. We do not know what is causing the fights.

If this sounds like it could be a description of middle school, you might be surprised! Chen, an undergraduate researcher at Duke University, is actually describing the captive parakeets that she observed, as part of a summer research project with Dr. Elizabeth Hobson’s lab. The social world of these birds involves paired interactions between birds that include an aggressor and a target.

There is an astonishing degree of variety in the types of paired interactions these birds can have! The birds naturally exhibit friendly behaviors or aggressive behaviors with unclear winners or losers. There are also several aggressive behaviors with more clear outcomes. Researchers group this final set of interactions, which are easy to measure, into a few types. In displacements, the actor forces the target to flee by approaching it within striking distance. In crowds, the actor forces the target to flee before entering the striking distance. In chases, the actor either repeatedly displaces the target in rapid succession or follows closely behind the target and prevents it from landing. Interactions with clear outcomes can be used to understand parakeet social hierarchies and cognition, which is at the heart of Chen’s work.

“It’s important not to anthropomorphize these birds,” Chen added. “Birds have a lot of differences from humans.” Birds evolved complex cognition separately from primates. Therefore, the reasons why individuals fight each other might have a totally different evolutionary basis in parakeets and humans. This separate history means scientists like Yuchen need to leave their anthropocentric preconceptions at the door when examining parakeet social life.

 

Parakeet Sexes Share a Leaderboard

Chen’s work expands upon other studies of parakeets, which showed that these birds have the cognitive capacity to remember their social history. In other words, parakeets can keep track of who wins and loses interactions. As a result, to understand these social interactions, Chen has been estimating the social rank of parakeets by monitoring a subset of these interactions that have clear outcomes of winning or losing. In this context, she defines rank on the basis of which birds consistently win or lose these interactions.

Chen has been evaluating a typical hypothesis for social behavior, which is that sex is an important factor structuring aggression and rank. She has been surprised by her results so far, which suggest that there is no distinction in how males and females interact with each other in these squabbles. “A lot of research examines female and male aggression and dominance separately, but neglects intersexual interactions,” Chen explained. “There is a common assumption that females and males have different rank hierarchies, as in alpha-male narratives, but this is not true for these parakeets. In our results so far, rank is a product of their social dynamics. These do matter, but they are not sex-biased.”

How Humans Conduct Parakeet Sociology

The clever methods the Hobson lab uses to study these birds make their work exciting and unique! Because males and females look identical, researchers need genetic testing from feather samples to sex the individual birds. Then, they paint the birds with colors. Because these markings allow the researchers to know who is who, they can keep track of what individuals and sexes are participating in paired interactions. “It is fascinating how they know who’s who, because we cannot even tell! It is hard to tell sexes, or individuals, even, but those parakeets know each other well, and visual marking does not impact their recognition of each other.” Chen explained.

 

 

 

 

 

 

 

 

 

 

 

For this study, researchers in Chen’s lab group studied five groups of ten individuals, totaling 50 birds. These birds were kept in large semi-natural flight pens (~35 ft long x 16 ft wide x 12 ft tall or ~20 ft long x 20 ft wide x 9 ft tall). They entered data about who fought whom and who won or lost, on an iPad. Having practiced some of these methods herself for a different data collection project, Chen noted she sometimes observed up to 500 fights in a six-hour day of observations!

The next steps for our Parakeet Society Specialists

After analyzing the data, Chen’s preliminary work put the relationships between parakeet sexes in a new light. She found little evidence that sex shapes social rank in these parakeets, challenging a common assumption about how dominance hierarchies are structured.

“We wanted to first test whether sex has a quantitatively convincing impact on an individual’s rank in the dominance hierarchy. Our work, which does not find evidence for a difference between males and females in their hierarchies, suggests the framework or assumption that sex is important for aggression may not necessarily be true for every species. It is important we check before assuming this,” Chen says. She encourages future work on other species to measure interactions between the sexes as she did, rather than only considering them separately, in order not to miss a potentially important component of social behavior.

While Chen’s work has suggested sex is not a strong influence for rank hierarchy in these birds, there are a lot of questions remaining about their cognition. One avenue for future research could be deciphering the motivations behind their behavior. “We do not even know the exact benefits they get from aggression and dominance,” Chen explained. Nor do scientists necessarily feel they have gained a complete picture of the rules behind parakeet social interactions in general. “Their captive behavior can be used to measure their cognition, but it is not necessarily reflecting what they do in the wild. The data on wild animals so far suggests they do form strong partnerships, but we would need various other angles of studying monk parakeets to fully understand these behaviors. We really want to know more…Every time I present to the public or other researchers, everyone is asking about whether it is same in the wild as in captivity!”

Chen’s research was conducted under the supervision of Dr. Elizabeth Hobson at University of Cincinnati and Dr. Sara Lipshutz at Duke University. They thank the fieldwork contributions from Madeleine Ball, Sophia Clemen, Nina Conklin, Jacqueline Golden, Megan Lieb, Charlotte Meigs, Darby Moore, and Lauren Stanfa.

 

Author Bio:

Meghan Rose Forcellati is a third-year Ph.D. candidate at the American Museum of Natural History’s Richard Gilder Graduate School, working with Christopher J Raxworthy on using an interdisciplinary approach to comprehensively study the evolutionary histories of amphibians and reptiles. Her current work focuses on studying DNA damage profiles in fluid-fixed museum specimens. When she is not in the lab, she enjoys powerlifting and reading.