But this strangeness exists even in our backyards. My imagination is stretched every morning by the neighborhood crows that I befriended on my street in 2016, after learning in Ackerman’s previous book, The Genius of Birds, that they recognize human faces. I’ve had four years to observe the behavior of one crow family. I’ve seen them groom one another, forage in the neighbor’s roof gutter, peck curiously at mushrooms, wipe their beaks on the power line, yawn, scold a hawk or cat (with different sounds for each), do barrel rolls when it’s windy, and sometimes follow me down the block, landing on various branches near my head. Lately they seem to enjoy my hiding a peanut for them under a pile of driftwood and pine cones, and they once moved a small rock from one side of my balcony to the other. Why they did this is … a deep mystery. The more I observe them, the less of a grasp I feel I have on them. Instead, they look more and more like willful individuals.
The crows also remind me that while birds and humans may see different worlds, we inhabit the same one, our alien universes stitched together at the point of contact, continually influencing each other. One day, overjoyed to find a bushtit nest down the street from my house, I realized that a scrub jay was watching me. Scrub jays, part of the same family as crows, are known to possess something like theory of mind, the ability to imagine what another animal is thinking. When burying a snack, if a scrub jay sees another jay watching, it will pretend to finish burying it, then come back and rebury it later. Jays also eat bushtit eggs. Noticing the scrub jay, I scurried away, thinking it might have used my behavior (stopping and staring) to locate the nest.
Birds respond to human behavior in the long term, too. Ackerman writes that zebra finches, facing a warming climate, have a way of communicating an instruction to their unhatched young to hatch smaller so that they lose heat more easily. Sibley notes that scrub jays are nesting five to 12 days earlier than they did 100 years ago, probably to align with plant and insect cycles affected by climate change. Some birds in urban areas have ramped up nighttime singing in response to increased daytime noise, and birds living in loud places have shifted the pitch of their songs higher in order to be heard. Of course, behavioral flexibility can go only so far. In September 2019, Science published findings that North America had lost close to a third of its birds in the past 50 years. One of birds’ broadest responses to human behavior, it turns out, has been to vanish.
Read: The quiet disappearance of birds in North America
There’s a large cemetery not far from where I live. For now, thanks to the abundance of trees and ponds, this area of rolling hills hosts an amazing variety of birds. Next to one of the ponds is a coast live oak tree and a grassy ledge where I like to sit and lie back. From there, I can look into the branches of the oak, waiting for the arrival of others. I have seen oak titmice, chickadees, house finches, goldfinches, white-breasted nuthatches, brown creepers, yellow-rumped warblers, Townsend’s warblers, western bluebirds, ruby-crowned kinglets, black phoebes, Bewick’s wrens, white-crowned sparrows, golden-crowned sparrows, California towhees, scrub jays, Steller’s jays, Cooper’s hawks, ravens, acorn woodpeckers, and, yes, bushtits.