If ever there was a species adapted for spring in the Maryland suburbs, it is the American toad.

Nimble, slimy and covered in warts, Anaxyrus americanus doesn’t need vast acres of forests to breed, like many of its avian counterparts. They’re not particular about clean waters, like the crabs waking up in the Chesapeake Bay every spring. They don’t need clean substrate, like the oyster larvae wafting down to land on a pristine shell.

No, American toads are delighted with leaf-covered yards, ephemeral potholes, and fragmented landscapes.

“Toads are the least picky of the amphibians,” said Scott McDaniel, executive director of the Susquehannock Wildlife Society, a nature center in Harford County that leads many hikes to peep at spring peepers and salamanders. “They will literally lay their eggs in a parking lot.”

And this is their time. Come the end of March, when the temperature hovers over 60 degrees and the warm spring rains let up, the compact American Toad and its less-common cousin, the Fowler’s toad, find their way to puddles in backyards and forests — known as vernal pools — and call out to their larger female counterparts.

The call is a high-pitched, bu-r-r-r-r, lasting up to 30 seconds. Once the female picks her mate, he grasps her behind her forelimbs, and they get to the age-old ritual of propagating the species. A stringy, gelatinous egg sack will sink to the bottom of the pool and become a tadpole within a couple of months.

In the rock band of a Maryland spring, the American toad is the bass player. Let the ospreys command the headlines heralding spring’s return, the bluebirds monopolize the photographers’ lenses. Anaxyrus americanus will take their place in the backyard, underneath the leaf pile, knowing the spring show can’t go on without their song.

“They probably don’t get the recognition they deserve,” said Beth Schlimm, state herpetologist at the Maryland Department of Natural Resources. “I love the way they look. They’re so grumpy looking. It’s hard to look at them and not smile — their little awkward hop. They’re so not graceful. It’s endearing.”

Despite their adaptability and ubiquity, the toads are facing threats from our modern world.

Rampant development means the loss of the vernal pools on which they have come to depend; rules that allow developers to replace established wetlands with new ones don’t provide equivalent habitat to what the toads lost. Because of climate change, spring migration for salamanders, frogs and toads has begun earlier, and often road salt from winter treatment has not yet dissolved into the pools. That means amphibians are absorbing salt through their sensitive skin, which can endanger tadpoles, according to Kerry Wixted, the Association of Fish and Wildlife Agencies amphibian, reptile and invasive species manager.

Climate change can also mean a deluge of rain, and then not much at all, drying up the pools when the toads most need to stay moist. When Rachel Carson wrote “Silent Spring,” she was thinking about not just the birds, but also the amphibians and their short window to make the species last.

“It’s a race against the clock,” McDaniel said. He plans a few night hikes a year to hear the toads; this year, he said, he went out and they weren’t peeping. That was a week or so ago, and he thinks they are more ready now.

Economic changes also harm toads. When farmers respond to high yield prices and plant more acreage of crops to reap more profits, the toads lose crucial habitat between field and forest, Schlimm said. Similarly, when farmers stock ponds with fish, toads can lose their natural pools.

Toads are also susceptible to two deadly diseases, Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans, known as chytrid fungus and Bsal. Chytrid has entered the United States from other countries through the amphibian trade, while Bsal is not documented here yet. Biologists are trying to stem chytrid’s spread. They recommend washing gear between hiking spots.

“If Bsal made it here, it would be absolutely catastrophic,” Schlimm said.

Maryland’s Department of Natural Resources keeps precise counts of important commercial species, like the blue crab, and also of endangered species, like the Eastern hellbender salamander. But it doesn’t keep an accurate count of the common toads. Every 15 years, the state completes an atlas of amphibians. But the sightings come from citizen scientists at random sites. The atlas doesn’t give strong indications of whether the numbers are rising or falling. For that, observers rely on anecdotal data from favorite spots.

Wixted, who lives in Anne Arundel County, recommends Jug Bay Wetlands Sanctuary and Severn Run Natural Environment Area, which is off Route 97 and New Cut Road. (Noise from nearby BWI Airport doesn’t seem to deter the toads; they’re hardwired for love.) McDaniel said last week he saw so many toads after a warm rainy night at his base on Darlington Road in Harford County that he had to swerve to avoid them. He recommends a visit to the Susquehannock Wildlife Society to see them in action after a couple of consistent 60-degree days, especially if they include some precipitation.

McDaniel and Wixted also recommend various nature centers in Baltimore County. Lake Roland Nature Center is a good base, and the elevated walkways allow for excellent observation. Cromwell Valley Park is pocked with vernal pools along its Mine Bank Run stream. Near Hunt Valley, Oregon Ridge Nature Center offers miles of trails ideal for hearing toad trilling.

Come for the toads; stay for what’s next. Soon, gray tree frogs and mountain chorus frogs will call. Barred owls might sweep in for a meal of amphibians. The Eastern hognose snake will play dead while using its rear-facing fangs to devour toads. And then there will be flowers: Virginia bluebells, Dutchman’s breeches, bloodroot.

“Everything comes to life, which is really special and worth celebrating,” McDaniel said. “There is something very special and ancient and primal about the connection we have with these animals, despite how modern everything is.”