Spring migration is a great time to catch a parade of birds passing through

After a long winter and an even longer COVID confinement, it's time for a change. Many of us are eager to get outdoors and experience the natural world as it greens up. As it turns out, this is precisely the time that nature is putting on one of its most spectacular shows, the annual return of migratory birds.

Millions of birds left Minnesota last fall for warmer places that guaranteed them a diet of insects and fruit. But now they're coming back. They're on the way to their breeding grounds, and for the next few weeks a steady parade of migratory birds will add color, song and flashing movement to our days.

Migration starts slowly: One day in mid-April common loons suddenly appear on a local lake, with acrobatic tree swallows swirling overhead. A pair of osprey reclaim the nesting platform they used last year and sandhill cranes bugle from marshes and open spaces.

Red-winged blackbirds sing "conk-a-ree" from the marshes, gray catbirds "mew" from clumps of vines and pairs of Eastern bluebirds reclaim nest boxes on golf courses and open spaces.

These early birds are all signs of the start of the gathering tide of birds migrating in spring. This annual ritual is one of the most awe-inspiring and reassuring events on nature's calendar. No matter what's taking place in our world, including pandemics, birds go about their lives, responding to their own imperatives.

Some species fly a few hundred miles to get here, but many others travel a thousand miles or more.

Jennifer Vieth, who heads up Carpenter Nature Center in Hastings, is in awe of bird migration, her enthusiasm covering everything from tiny saw-whet owls to turkey vultures to nighthawks.

"That wood thrush we see in Minnesota in the spring has made it all the way back from Venezuela," she notes. "Birds fascinate us with their variety and resilience and the incredible distances they travel."

Brilliant orange Baltimore orioles winged out of the tropics in late February to sing their whistling songs from the treetops, beginning in early May. The tiny ruby-throated hummingbird that zips in to a nectar feeder in May made an epic flight across the Gulf of Mexico, covering 500 miles nonstop.

Spring migration starts with a trickle in late March, becomes a river of birds in April and builds to a flood in May. A month from now the woods will be alive with the songs of bluer-than-blue indigo buntings, the raspy notes of scarlet tanagers and the rich burbles of rose-breasted grosbeaks.

But this passage of birds is almost invisible to us because most of the more familiar birds, the songbirds, migrate at night, to avoid predators and to take advantage of cooler temperatures. We can see them in the daytime, however, as they rest and get ready to fly farther north.

What's a good time to look for migratory birds? Morning hours are best, the earlier the better. Migrants generally fly until the sun rises, then begin to drop down into trees, shrubs or onto the ground to rest and find food to rebuild their energy reserves. But if you simply aren't an early riser, another option is to start looking for birds in the evening, before sunset.

Where should you go to see migrants? Most migrants don't visit bird feeders, so you'll need to go where they are. They may visit your own backyard, if you have a variety of trees and shrubs to offer food and shelter. Or, go for a walk along a nearby creek or river, since migrants often choose to be near water. They might also be found at the edges of woods and near marshes. The Twin Cities area has many nature centers, each of them offering a variety of habitats that attract a variety of birds.

If you're new to this bird-watching thing, how will you know if a bird is a migrant or has been here all along? Here's where a book devoted to birds and their locations — a field guide — comes in handy. If you see a bird that seems new to you, try to find it in your guide (either in printed form or a cellphone app). One surefire way is to ask a friend or family member who's a bird-watcher to point out migrants for you on a bird hike.

Birds don't migrate en masse; instead, each species has its own migration window, with early birds arriving at the front end, latecomers near the end and a peak in the middle. For example, the first Eastern bluebirds show up in early March, their numbers peak in April and arrivals continue at a slower pace into mid-May.

Carrol Henderson has fond memories of birds returning to his grandparents' Iowa farm each spring, fascinated by his grandfather's looking to one species as a guide. "He wouldn't start planting corn until he saw barn swallows return, around May 10 or so," says Henderson, retired head of the state's Nongame Wildlife Program and lifelong bird-watcher.

Many of spring's migrants spend only a day or two here, then they're off again, in a tearing hurry to claim a territory and raise a family, in many cases in Canada's forests. Some do nest among us, however, including catbirds, the Eastern phoebes that claim the porch overhang each year and the house wrens that noisily commandeer backyard nest boxes.

After a year spent close to home, confined and constrained by a dangerous virus, we can be reassured by bird migration that life goes on and better days lie ahead.

This annual movement of birds is a phenomenon that many of us take for granted — but we shouldn't. It's happening all around us, with new birds appearing every day. But it won't last long — by late May only the stragglers will still be on the move. It's an awe-inspiring show, and it's free and available to anyone willing to look and listen.

St. Paul resident Val Cunningham, who volunteers with the St. Paul Audubon Society and writes about nature for local, regional and national newspapers and magazines, can be reached at valwrites@comcast.net.

Robins used to be sure harbingers of spring, but they've had to give up that title, since so many now spend winters in our area. But once robins start singing their loud songs, then we know spring has sprung.

Check out these sites for a status report on which birds might be coming your way soon:

journeynorth.org/hummingbirds: This site's maps will let you know when to make sure your hummingbird feeder is ready for business. First-sighting maps are available for a handful of species, including robins, hummingbirds and red-winged blackbirds.

birdcast.info/migration-tools: This site offers a bird migration forecast map and live bird migration maps. There's also a local migration alert tool to detect whether birds are migrating in your area that night and in what densities.

ebird.org: You can track migratory pathways of specific bird species in maps or bar charts.

allaboutbirds.org: Another approach is to select some key migrants you'd like to see, then check out each species to find when it might appear.

How far do birds fly to get to our area? Here are some averages:

Baltimore oriole: 1,000 miles

Indigo bunting: 1,200 miles

Osprey: 2,600 miles

Common loon: 1,100 miles

Ruby-throated hummingbird: 1,500 miles

Gray catbird: 1,800 miles

Red-winged blackbird: 800 miles

Tree swallow: 1,800 miles

Barn swallow: 2,800 miles

Eastern bluebird: 500 miles

Turkey vulture: 1,200 miles