They’ve been buried — alive — for 17 years.

And now, Brood X, one of the world’s largest swarms of giant fly-like bugs called cicadas, is ready to rise. When the ground warms to 64 degrees, they’ll stop gnawing on tree roots and start scratching toward the surface by the hundreds of billions.

Georgia and other Southern states will probably be where they first emerge around the end of March, experts say. But residents of the Washington area are standing at ground zero. The District, Maryland and Virginia are likely to host more of these animals than any other of the 14 states that share the experience.

“We are at the epicenter of an event that happens nowhere else on the planet except here in the Eastern United States,” said Mike Raupp, a University of Maryland entomologist who travels the country giving speeches about cicadas.

“It’s going to be pretty remarkable, come the latter half of May,” Raupp said. “The densities of these things is going be phenomenal, about 1.5 million per acre. It blows your mind.”

Cicadas are expected to appear in tremendous numbers across D.C., Maryland and Northern Virginia in the spring of 2021. They have lived underground since 2004. (Kevin Ambrose)

If you imagined there were more birds outside your windows last spring because of the pandemic quarantine, you haven’t seen anything yet.

Cicadas are a Thanksgiving-like feast for wildlife. As they emerge, birds, squirrels, chipmunks, skunks, ants, raccoons, snakes, frogs and possums will gorge themselves for about a week until they collapse into food comas.

“What people will actually see is animals eating bugs,” said Gaye Williams, an entomologist for the Maryland Department of Agriculture and an avid cicada watcher.

Yes, she said, your dog will eat cicadas if given the chance.

“It’s very much like when you go to an all-you-can-eat crab feast,” Williams said. “The very first bunch that you throw down on your table, everybody grabs crabs and you start cracking them, and you take every last molecule of crab meat. About the fourth tray … people only take the claws. As this orgy of eating goes on, there are animals that actually won’t touch them anymore. They’re full.”

The sacrifice of a few thousand lives won’t faze Brood X. It will carry on with its single-minded purpose: courtship, sex and hatching the next generation of cicadas.

After tunneling their way out of the ground near tree trunks, they’ll crawl up trees, or things they mistake for trees, and shed a thin shell from which they emerge as Technicolor animals with big orange eyes and wings.

The males will start mating songs that reach up to 100 decibels. “That’s the sound of a chain-saw, a lawn mower, a jet overhead,” Raupp said.

And then they will get busy. To paraphrase an old hit song, they will do it like they do on the Discovery Channel — in trees, on your patio, your porch, your yard, your roof and your car. It might be a good idea to keep the windows closed.

Humans will see an undifferentiated mass of bugs. But in reality, Brood X is composed of three species Magicicada septendecim, Magicicada cassini and Magicicada septendecula. They’ll sort into different trees and make three distinctly different male songs.

Adult cicadas die after intercourse. Females stick their eggs into the branches of trees, then keel over. The eggs hang out for a while, then hatch, and the nymphs fall to the ground and dig down to a nice tree root, which they nibble on for 17 years.

The process is somewhat harmful to trees, said Eric Day, an extension entomologist at Virginia Tech. He recommends that farmers and homeowners not plant saplings until July, when all the cicadas in the area have died.

“One female can lay 10 to 20 eggs,” he said. “She makes a long cut on [a] twig and deposits them.” The eggs are tiny — but do the math, he said. There are billions of females.

The last time Brood X appeared, Greece was preparing to host the Olympics, Barack Obama was a state senator in Illinois, and President George W. Bush was fighting for a second term.

Brood X has experienced a bit of fame. After emerging in 2004, its members could be heard during the nationally televised Memorial golf tournament in Dublin, Ohio, featuring Tiger Woods and other pros. At one point, Woods could be seen looking at the trees, amazed by the waves of sound.

Cicadas also made an appearance on “The Tonight Show With Jay Leno” when Brood II emerged in 2013. On one night, Raupp, who might be best described as a cicada whisperer, famously fed a bug to the host. Raupp offered a bite to actor Russell Crowe, seated to his right. Crowe declined.

“I’m going to eat some cicadas,” Raupp said. “Boiled, fried on skewers.”

Christine Simon is planning to drive from Connecticut to Georgia to check them out. The Washington area will be one of her first stops. Simon, a professor of ecology and evolutionary biology at the University of Connecticut, has studied their languages.

“The song of the first species sounds like a flying saucer landing from a 1950s science fiction movie,” Simon said. “The middle species sounds like someone took water and threw it into hot oil. The third one sounds like an angry squirrel.”

Simon expects to find a ton of cicadas along the banks of the Potomac. “I think they’re in Rock Creek Park,” she said. “I’m not absolutely certain, but I think they are.”

If you want to help locate cicadas for science, there’s an app for that. It’s called Cicada Safari and it’s free. When you see cicadas, you can snap a picture within the app that will automatically go to Mount Saint Joseph University in Cincinnati, Simon said.

There, a team of students will map them for future study and to show cicada lovers where they are. The University of Connecticut maintains a map of Brood X.

Simon and Raupp will take you to school on periodical cicadas. The animals that emerge in the present day date back 3.9 million years. They split into different broods about half a million years ago. Twelve broods, like Brood X, emerge every 17 years, and three every 13 years.

A small number of annual cicadas appear yearly and are hardly noticed.

Sometimes, 17-year cicadas jump the gun because of climate change. Millions of Brood X cicadas bore to the surface in 2017 a bit too early in Herndon, Va., in Wolf Trap National Park for the Performing Arts and along the Potomac to Reston.

That was Brood X four years early, Simon said. Early cicadas are essentially devoured by predators.

“I’d say twice as many were still underground,” said Simon, who’s observed cicadas since 1974. “That lowers the numbers.”

Humans have also reduced the swarm’s population. First the colonists cut the trees the bugs need, clearing land for expansive farms. Then developers built houses, business centers and shopping centers over surfaces where they emerge.

Invasive species of birds brought by humans picked off more than their fair share. Squirrels introduced to cities near the turn of the last century by urbanites who craved wildlife became a predator cicadas hadn’t faced.

On top of all that, said Williams, the Maryland entomologist, a natural fungus attacks male cicadas in the most personal way.

“They can’t mate if they’ve got the fungus,” Williams said. “They got, what’s it called, no junk. It’s laying on the ground somewhere.”

The fungus looks powdery, brown like cinnamon. It goes after the abdomen and infects other cicadas when it sprinkles as the afflicted bugs fly. “If you search ‘Flying Salt Shakers of Death’ you can learn more about it,” Williams said. “Oh my God, it’s incredible.”

Males transfer it into the eggs of females in their sperm, infecting the next generation.

Cicadas went extinct in Connecticut and northern Florida, and have dramatically declined virtually everywhere, especially in Georgia and other Southern states.

Some people are happy about the decline. They dread cicadas as much as they do spiders or any other type of creepy crawly.

But cicadas have a legion of fans who travel to see them. There is such a thing as cicada envy, people who are peeved that the bugs don’t show up where they live. Parents take their kids to watch them the instant they push out of the earth, making a tiny dirt cone.

“If you’re in a place where they were in 2004, there’s going to be a magical evening; right around sunset you are going to go out, and there will be hundreds of thousands of these things emerging from their crypts, marching in column,” Raupp said.

“And if you stand still, they will climb up you and shed their skin.” If you miss them somehow, be patient.

Brood XIX, the largest known swarm with the widest range, is coming in 2024.