Have you seen a robin yet?

When I was growing up, my mom would spend early March on the lookout for robins. They were, she told us, heralds of spring. Spotting the first robin out on the lawn was the first sure sign that winter was over. If you live in North America, it's probable that you learned something similar about these ubiquitous thrushes, with their persimmon bellies. This time of year I'll often be asked a question by park-goers who spot me with binoculars around my neck:"Have the robins arrived yet?" It was only when I started paying closer attention to birds that I learned the little-known truth about robins in North America: they're always there. Unless you live in the prairies, or in the far north, robins are year-round birds. In New York City or Seattle or D.C. or Memphis, there's not a day in the year when you can't find a robin, if you go out looking for one.

If you go out looking for one. This is the trick. Robins are omnivores; they prefer to eat insects but they can also forage for seeds and fruit. Robins are particularly well-adapted to eating waxy berries like holly, bayberry, and mistletoe. This is the reason they don't need to make a long spring migration. The high-fat content of the berries keeps them warm through the winter months. The robins' dual food source lifestyle means that, depending on the time of the year, the birds behave quite differently. In the spring and summer they are poring over lawns, step-by-step, looking for earthworms and larvae. In the colder months, they're up in the trees eating their waxy winter fuel.

The spring "arrival" of robins that my mom was on the lookout for is indeed an arrival, just on a smaller scale than most people think. They're not arriving from some exotic summer wintering spot; they're arriving down from the trees.This speaks both to our human patterns of attention and to the invisible phenologies of nature. Our attention, particularly in urban lives, tends to be pointed down rather than up. This makes sense. We're watching for cars, reading street signs, trying not to step in puddles. We're looking down at our phones. A robin on a lawn is much more likely to be noticed that a robin in a tree.

I often tell beginner birders that the hobby opens up a full 50% of the world– the world in the sky but also the world high in the crowns of trees and perched on power lines. Seeing robins on the lawn in the spring is a sure sign of the end of winter. To notice them step-step-pecking for worms is to welcome a moment where thousands of insects have woken up from their winter dormancy. An entire ecosystem waking up, signaled by the careful foraging of a red-bellied thrush.This post is the lecture I don't give to people when they ask me "have the robins arrived yet?" It's a correction that none of them need. "I have seen the robins," I say with genuine glee.

"Spring is here."