Parakeet males, females equally likely to fight

The work, led by undergraduate researcher Yuchen Chen with co-authors Sara Lipshutz (Duke) and UC Associate Professor Elizabeth Hobson, was published in the journal Integrative & Comparative Biology. 

The study started from overlapping interests within the research team in how the sex of individuals can shape many characteristics and behaviors of species combined with the importance of aggression and hierarchies within groups. Females and males parakeets look identical.

“Because we can’t tell a female monk parakeet from a male based on their appearance, I started wondering about the effect of sex on their behavior, particularly aggression and dominance,” Chen said.

“In a lot of animals, you see differences in aggression and how hierarchies form between females and males. But our new results show that we don’t observe any major differences between female and male aggression or rank in our parakeet groups,” UC's Hobson said.

In her lab in UC’s Department of Biological Sciences, Hobson studies animal sociality and cognition. She has been working with monk parakeets for 20 years. One thing monk parakeets love to do is squabble.

They spend much of the day exerting dominance over others in behaviors such as taking over another’s perch.

“In the parakeet groups, the birds fight a lot, which gives us a lot of data to analyze, but these fights are usually minor squabbles, and it’s extremely rare for them to injure each other,” Hobson said.

These frequent squabbles could be a way the parakeets resolve social differences.

“Many previous studies have studied aggression and dominance in a sex-specific manner or only in one single sex. Since we observed all of the parakeets interact, we decided to examine both aggression between individuals of the same sex and across individuals of the opposite sex,” Chen said.

“Group living involves frequent interactions among individuals. Low-stakes squabbles can build a social hierarchy that prevents more intense, dangerous fights,” Lipshutz said.  

Besides engaging in fights, monk parakeets are keen observers when others fight. Watching closely who wins and loses helps them know where they stand in the hierarchy and what fresh opportunities exist to improve their standing, researchers said.

Understanding more about how sex affects social interactions and aggression helps us better understand why females and males may interact differently sometimes, or more similarly in other circumstances.

“For some species, sex differences in certain behaviors can be small or even absent, despite what we might expect from existing assumptions or biases. A well-designed experiment with robust statistical analysis is necessary to test whether sex differences actually exist,” Lipshutz said.

“I had a suspicion from watching them for so many years that the sex of the birds wasn’t really affecting aggression. We tend to get a 50-50 split in sex for who becomes the top-ranked bird in our groups. But it’s important to formally test these suspicions, which is what we did in this study,” Hobson said.

“I think the main takeaway is to not make strong assumptions about animal behavior without collecting data and testing for patterns. It’s important to be careful about the kinds of pre-existing notions because they can lead to unsupported biases and wrong conclusions,” she said.

If you ask the parakeets? They just love a good fight, regardless of their opponents.

Featured image at top: Male and female monk parakeets are equally prone to fight for dominance, researchers say. Photo/Sydney Austin