Q&A: The drama of a bird’s nest

A dark-colored bird perches on a tree branch

A greater ani. Credit: Arthur Chapman / Flickr (CC BY-NC 2.0)

An SF State biology professor answers questions about cooperation and conflict in nature

Andrea Swei


This story originally appeared on the University’s Bold Thinkers blog, which ran from May 2018 to Nov. 2019.

Watch animals interact long enough, and you might start to see a soap opera — or maybe a cold-hearted crime, or even acts of selflessness. Either way, when witnessing animals in the wild it’s hard not to see bits of humanity in them.

Associate Professor of Biology Andrew Zink has spent two decades studying animals ranging from insects to birds to learn about what might seem like human-like aspects of behavior: cooperation and conflict. On Feb. 27 he published a “News & Views” article in the journal Nature commenting on the importance of a new study by researchers at Princeton on a species of cuckoo called the greater ani. Here he discusses that study and some bigger questions about his work and the field as a whole.

Can you tell me a little bit about the new study you wrote about in Nature?

The researchers found a unique connection between cooperative breeding [multiple females sharing a nest] and brood parasitism [abandonment of parenting duties]. It’s completely different than how we had been thinking about it previously. In the anis, when a shared nest gets destroyed, a subset of the females in the population lay an extra egg in another female’s nest instead of holding off until the next breeding season. Certain females repeatedly do that when their nests are destroyed, and other females don’t. The researchers show why that parasitic tactic has evolved, and demonstrate that both strategies are equally successful over multiple seasons. It’s rare to find both parasitism and cooperation in the same population, and before this no one had been able to get enough long-term genetic data to make that kind of comparison. 

Why are these questions something that scientists want to study in animals?

One reason is that cooperation and conflict are so directly relevant to our day-to-day experiences: They’re part of human behavior, so it’s interesting to ask how other animals that are less influenced by culture negotiate similar situations as a result of evolution. It also lends itself very well to elegant math like game theory, a branch of economics that describes how humans make decisions. And possibly the most important factor is that cooperation and conflict are universal themes in biology. I can have a conversation with someone who studies cancer: They may be talking about cooperation and conflict between cell lineages, while I’m talking about a similar phenomenon happening within animal societies.

What have you been working on recently?

Something I’ve been interested in recently is how mutually beneficial interactions between species, which we call mutualism, can actually stabilize cooperation within a species and vice versa. This applies to everything from termite societies that share microbes to decompose wood to mammal societies with shared bacteria that help them to digest plants and meat. There’s even a recent model suggesting that shared mutualistic bacteria could stabilize cooperation in human societies. My graduate students at SF State have been researching the importance of mutualistic bacteria on salamander skin, in offspring care by earwigs and in the light organs of bobtail squid.

How do you feel about talking about animal drama like they’re people?

Many behavioral ecologists have no problem talking like that, while others have an issue with it. I think you can’t deny how fun it is to draw analogies with human behavior, as long as you know ultimately that it’s more complicated than that. Of course, it really depends on the species. If I’m talking about an individual ant, I’m not going to ascribe human attributes like fear or compassion to it. But when you’re talking about an animal such as a raven or a whale or possibly even an octopus, I don’t think it’s a stretch at all. It’s accurate to talk about them as having subjective experience, in terms of “wanting” or “desiring” or having intention.