Spring at last is right around the corner. We’ve been having a rare mild and snowless winter, and February school vacation week brings early signs of spring in the woods, such as pussy willow and skunk cabbage blossoms.

But where are the robins? Peering out our windows, we wait for that classic sign of spring, robins hopping on our lawns, looking for worms.

Most of the robins that went south last fall haven’t yet returned, but there are robins in the woods. We think of robins as eating earthworms, but in the fall and winter they switch to fruit and berries. They find these foods in the woods, and as you may have noticed, on ornamental fruit trees in yards and parking lots. They spend their time in flocks, avoiding snow-covered areas and traveling around to trees and bushes with fruit and berries.

You might spot robins in the trees if you walk the paths at Mass Fish and Wildlife’s Westboro Management Area. And keep your eye on ornamental trees that still have dried fruit on them, such as cherries or crabapples. Robins and other fruit eaters such as cedar waxwings eat the most nutritious fruits and berries first, but as winter ends the flocks descend on whatever remains.

Robins’ beaks and digestive systems are suited to worms, insects, and fruits and berries, so you probably won’t see them at seed-filled bird feeders. Even when they eat fruit, they promptly spit out most of the seeds, and those that remain pass quickly through their digestive systems and get spread across the landscape in droppings.

Who are these robins in the woods? They may include some of the robins that nested here in the spring, but most are likely to be robins that came here from places farther north. Some may even have come from Canada. They’ll move northward as the weather warms.

As the ground thaws and stirs with life, robins that migrated south will begin to return and hunt earthworms that wriggle toward the surface from deep underground. These robins usually arrive when the mean daily (24-hour) temperature rises above 37 degrees F, generally in March.

How do robins find those earthworms? A robin can capture up to 20 earthworms an hour. We’ve all seen them stand and wait, cocking their heads, and then strike the ground with their beak to grab and pull up an earthworm. Are they listening or looking for worms? Research suggests they do both. They locate a worm at first by hearing its underground movements, but then their eyes show them exactly where to aim their strike. Because their eyes are on the sides of their head, they cock their heads to look with one eye and then the other.

Robins tend to come back to the same areas where they nested before. The robin that nested in a bush outside your window might even do so again.

As with many birds, male robins return first. They are more brightly colored than females, with blacker heads and backs. You may notice them on lawns, skirmishing over territory by making runs at one another. Females return a few days or so later. Their heads and backs look brown rather than black, and their orange breasts are paler.

Both males and females focus more on returning to good territories than on finding the same mates, so the pair that forms on a territory may not include both of the same birds from last year. Territories are usually about one-third of an acre.

Robins are famous as early birds that nest earlier than most songbirds. You may get to see a bit of their family life because robins don’t seem to mind nesting near people. If you see a robin fly off with an earthworm instead of eating it, you’ll know it has young nearby. In our area robins typically raise two broods. A pair’s first nest of the season may be sheltered in evergreens.

Robins build sturdy cup nests. Even if you don’t get to see a nest, you may notice both male and female robins gathering nesting material. The female builds the nest. For the outer layer, she uses coarse grasses, rootlets, leaves, and even string and bits of paper. She sits in the midst of a growing pile of material and shapes it into a cup by turning her body and pressing it against the sides. Then the pair gathers mud, which strengthens the nest. They carrying mud in their beaks or on small bunches of grass, and the female presses it into the grass cup with her body. If you spot a robin with a muddy streak across her breast, you’ll know she has been working on a nest. Once the mud layer is complete, the robins bring fine grasses for a soft inner lining.

Robins are also early birds when it comes to song, as we often discover as days get longer and more and more robins return. Robins sing earlier in the morning than most other birds. Their dawn chorus begins at the first hint of dawn, sometimes waking us by 3:30 or 4 a.m. People often describe the robins’ song as “cheerily, cheer-up,” but robins are thrushes (as bluebirds also are) and have a large, varied repertoire that other robins, at least, can appreciate. Robins sing as many as 70 different songs, running through one after another. They sing most just before their eggs hatch, and then become quieter.

As schoolchildren learn, robins’ eggs are sky-blue (like those of bluebirds and most thrushes). They typically lay four. If you have a nest to watch, the young seem to be gone shortly after you realize they’re there. Robin family life goes by quickly, in stages of about 2 weeks each. The female warms the eggs for about two week as the young develop inside them. Newly hatched robins are naked and pink, with eyes closed. They develop feathers and grow quickly on a protein diet of worms and insects. One young robin was recorded eating 14 feet of earthworms in a single day. The young stay in the nest for about two weeks, but the parents continue to feed them for another two weeks after they leave the nest, while the young improve their flying and hunting. Juveniles look much like adults but have a thrush-like spotted breast for camouflage.

After raising a second brood, robins sing much less, but during the summer you can often hear them making a call that sounds like a laugh or whinny. In the fall, many males, females, and juveniles gather in flocks and depart for warmer parts. On the way, they may roost together at night in huge numbers. In late October 2010, up to 68,000 robins were reported roosting in Sterling, MA, not far from here.

In spite of these impressive numbers, life is short for robins. More than 50 percent of adults die each year. Only 1-2 percent of robins live to be 3 years old. Migration, the stress of early nesting in changeable spring weather, and the vulnerability of open-cup nests to predators all take their toll.

Our American robins (Turdus migratorius) got their name from European colonists, who named them after the robins of Europe (Erithacus rubecula), which have a red breast but aren’t closely related. The name was in use by early 1700s when Westborough was incorporated as a town.

Our robins were originally birds of the forests, but they adapted as colonists cleared the landscape for farming and brought earthworms from Europe. When settlers pushed westward in the early 1800s, bringing earthworms with them, robins followed. Robins are adaptable and tolerant of fragmented habitat, so they’ve made themselves at home on suburban lawns and in city parks.

Connecticut, Wisconsin, and Michigan all claim the robin as their state bird. But here in Massachusetts (where our state bird is the black-capped chickadee), the robin is a long-awaited sign of spring.