Spring (ahem – mud season) is almost here, but of course, this is Maine. You wouldn’t know it by the weather. But if you pay attention to another of Mother Nature’s rituals, you’d know beyond a shadow of a doubt – the return of migrant birds ushers the season in with a flourish, weather be damned (well, to a point…).

They’ve only just begun to arrive, and contrary to conventional wisdom, it isn’t only robins that herald spring. American robins may overwinter in northern climes as long as they have access to winter fruit; they have wintered in Maine, especially along the coast. And even if resident robins head farther south, those up north may move in and stay awhile. They won’t travel more than they can help it – especially the males. They want to remain as close to their summer range as possible; this sets the stage for them to reclaim prime breeding territories come spring.

No, it isn’t only the robin that is the true harbinger of spring. It is the raucous flocks of red-winged blackbirds and common grackles, the swift-winged woodcocks, and the darkly graceful turkey vultures.

Blackbirds? Turkey vultures? Yep. They’re much more than the stuff of Hitchcock Horror.

Common grackles and red-winged blackbirds are two of our earliest “arrivals,” although they, too, will be present year-round as far north as Massachusetts and New Hampshire. In addition, bird identification guides show them as being resident year-round in Nova Scotia, where maritime influences moderate the climate to some extent. Still, for many people spring hasn’t arrived until the first liquid notes of red-winged blackbirds and the squeaky-hinge voices of grackles ring out in the neighborhood.

The same can be said for the odd little denizen of the forest edge and open field – the American woodcock. Wintering along the Gulf Coast and present year-round in the southeastern U.S., this bird would be sorely missed if it never returned to Maine. Brisk, damp March and April evenings would be empty without its spiraling courtship flight and territorial “peents.” As one person on a birding e-mail list wrote, “Spring has just flown into Durham. One lone woodcock in the fields adjacent to the Davis Road yesterday at dusk.” That says it all.

And the turkey vulture? Several have been reported in the last few weeks, migrating back from the southern U.S. and South America. A bird that thrives on eating carrion doesn’t usually evoke spring-time emotions. Still, their arrival is indicative of the advancing season, and in some areas of the country their appearance is an event. People in Hinckley, Ohio, for instance, have a “Vulture Festival” to celebrate their return every spring. No kidding.

Our resident birds are harbingers of spring, as well. Many of our common loons spend the winter offshore, returning inland as soon as ponds and lakes begin to open up. For some people this is a sure sign of spring.

Hey, how about a “loon festival?”

Chris Corio, a volunteer at Fields Pond Audubon Center in Holden, can be reached at fieldspond@juno.com