During the first two weeks in May, an estimated 3 billion to 5 billion song birds will migrate from Mexico, Central and South America into North America to breed. It’s an epic journey richly enjoyed by experienced birders and first-timers alike.

Some migratory birds are already here. For instance, a pair of osprey hawks arrived outside the Borough of Stonington on or about March 26, claiming their nesting platform, set back from the road in a marsh at the intersection of 1 South and 1A West. These popular, black- and white-colored “fish hawks” winter as far south as the West Indies.

Elsewhere, at my feeders for two weeks now, I’ve seen large mixed flocks of red-winged blackbirds, common grackles and brown-headed cowbirds, haggling over birdseed that I throw on the ground for them. And, a rufous-sided towhee, a colorful ground-dwelling bird that has a fun “drink-your-teee” sounding song, arrived in my back yard on April 19. They may winter as far south as Guatemala.

Three other long-distant migratory birds that I can’t wait to see flash into my yard in the coming weeks are: Baltimore orioles, rose-breasted grosbeaks and, my all-time favorite, the ruby-throated hummingbird.

Baltimore orioles take their name from Lord Baltimore, founder of the colony of Maryland, who had the same striking orange and black colors in his family coat of arms. These drop dead gorgeous birds can be attracted to feeders with slices of oranges or grape jelly, reminding them, perhaps, of the sweet tropical fruit they eat when wintering in central and northern South America.

Rose-breasted grosbeaks are unrivaled for their beauty as well. “Bursting with black, white, and rose-red, male rose-breasted grosbeaks are like an exclamation mark at your bird feeder or in your binoculars,” writes The Cornell Lab of Ornithology’s website, “this is a bird that has a chirping, sweet, beautiful song and loves to eat black oil sunflower seeds.

And then there is the ruby-throated hummingbird, one of the few birds in the world that can fly forward, backward, upside down and hover, like a helicopter, beating its wings 53 times a second.

The only “hummer” regularly found east of the Mississippi, ruby-throated hummingbirds typically fly to the Yucatan Peninsula in late February or early March, where they stay for a week or two, fattening up on insects. They gain an extra 25 percent in body weight, which they will need when they transit the Gulf of Mexico, a daunting, non-stop, 500-mile journey across a featureless ocean, truly an amazing feat.

How do birds like orioles, rose-breasted grosbeaks and hummingbirds migrate? It’s still a mystery. But scientists believe migratory birds navigate by using a combination of stars, the sun, the pull of the earth’s gravity and possibly smell.

Why do many migratory birds fly at night, rather than during the day? It’s believed there are fewer predators at night (hawks don’t fly during this time), the winds are calmer and the temperatures are cooler during these hours, when the birds are exerting tremendous energy, burning a quarter of their body fat, flying perhaps 300 to 500 miles a night.

Most of us are asleep when these incredible migrations occur. But if you are lucky enough to witness a “fallout,” usually in the early morning hours, hundreds of thousands of birds may come down out of the skies, exhausted, as you can imagine, and rest and hunt insects during the day in nearby parks, forests, nature preserves or along seashores.

Where can you see these wonderful birds? Start with your own back yard, or when you walk your dog in the morning or in the early evening. Take a few moments to look up in the trees and you may be surprised at what you see. It’s even better if you bring binoculars.

Some of my favorite birding hotspots are: Pequotsepos Nature Center in Mystic, Barn Island in Pawcatuck and Ninigret National Wildlife Refuge in Charlestown, R.I. Enjoy.

Bill Hobbs is a resident of Stonington and a life-long birder. For comments, he may be reached at whobbs246@gmail.com.