Mind & Matter: How a Falcon Can Become a Stepfather

"In 2016, a pair of peregrine falcons, the cliff-dwelling birds of medieval romance, settled into a new home. But these 21st-century falcons chose a city high-rise instead of a bare mountain peak. They nested at the top of the Berkeley Campanile, my university's bell tower, and in the 21st-century way, their falcon-cam video stream made them into YouTube stars. The Berkeley ornithologists named them Annie and Grinnell, after the founders of the school's zoology museum. The falcons raised new chicks each spring, and in these difficult years, thousands of fans have found consolation and joy in watching them.

Then on March 31 an urban tragedy struck. A car speeding down Shattuck Avenue killed Grinnell just after Annie had laid their eggs. Falcon chicks need two providers, so they seemed doomed. But there was a remarkable plot twist. Within a day a new male joined Annie, named Alden after Grinnell's successor at the museum. Alden began feeding and taking care of Grinnell's children -- now two happy, healthy young falcons. It was a rare 2022 happy ending and yet another consolation and joy for the Berkeley falcon followers.

Scientifically, though, this hopeful story is puzzling. Evolution unromantically selects for the survival of an animal's genes. So why would Alden put all that work into raising another falcon's babies? It's a particularly relevant question for us humans. Most mammal mothers take care of their babies by themselves; chimp moms won't let other chimps get near their infants. But human fathers, grandparents, siblings and people who aren't related at all -- "alloparents" -- help care for babies. In her great book "Mothers and Others," the anthropologist Sarah Hrdy describes how many different people pitch in -- the proverbial village. A select group of other mammals alloparent, too, including marmosets and wolves.

Allen Fish, one of the Cal falcon-cam scientists, connected me to a veritable brain trust of falcon ornithologists, and a long, fascinating thread ensued. The experts agreed on the same basic story. Alloparenting often emerges when raising the young requires a big investment. For humans, the challenge is that our babies, with their big brains, need an exceptionally long time to learn how to take care of themselves. For falcons, it's all about real estate. A good cliff is as hard to find as an affordable two-bedroom in San Francisco, and for falcons, the campanile is a rare gem. Bachelor "floater" falcons like Alden hover around established pairs looking for a chance to move in. From a genetic point of view it's worthwhile for Alden to take on the cost of investing in Grinnell's chicks for a season, if it means that he gets to impress Annie and live in the tower for many seasons to come.

What are the mechanisms that lead to this desirable evolutionary outcome? The costs and benefits of raising unrelated young play out differently for different species. Blue-footed boobys, for instance, will kill a chick that they doubt is theirs. But for falcons in the breeding season, the very fact of seeing eggs, or begging babies, seems to trigger the impulse to care. Studies show that this happens to alloparenting mammals too, including humans. Just holding a baby can bring on a rush of warm and fuzzy hormones.

We humans envy the falcon's gift of swift and graceful flight. But our big brains and vivid imaginations allow our own kind of travel. We can see other people's helpless children in peril thousands of miles away, in Uvalde, feel the drive to care for them and work on how to act to make that happen, even if it means making laws instead of nests. As Emily Dickinson wrote, hope is the thing with feathers." [1]

1. REVIEW --- Mind & Matter: How a Falcon Can Become a Stepfather
Gopnik, Alison. 
Wall Street Journal, Eastern edition; New York, N.Y. [New York, N.Y]. 11 June 2022: C.4.