Lots of animals have spring rituals. People do, too. Some rush to the garden center. Annapolis boaters burn their socks. And George Grall straps on a headlamp.

He's not alone. A small army of people, passionate about frogs and salamanders, watch the skies and the temperatures. When the moment is right — and the best moment is in the middle of a mild rainy night — they grab their headlamps and head out in the dark.

They seek vernal pools, where the circle of life is in full swing. Vernal pools are the shallow, temporary ponds formed by winter snow and rain. Most are gone by summer.

They are too small and they disappear too quickly to be of any use to fish. And that makes them the perfect, predator-free breeding ground for frogs and salamanders. On early spring nights, they emerge from hibernation in large numbers and migrate to a nearby pool to mate and lay eggs.

Grall, a Maryland wildlife photographer, has been fascinated by the phenomenon since he was a teen. You can find him in the dark, often in the rain, laying on a boogie-board to capture underwater images of spotted salamanders, wood frogs, spring peepers and more.

"What really drives people like me to go to these places is that you never know what you're going to see," Grall said.

Scott McDaniel ,of the Susquehannock Wildlife Society, leads night-time trips in Harford County, MD, to witness the spectacle. One of the earliest amphibians to make a migration is the spotted salamander, with yellow-orange spots on a thick dark body that when full grown is 6–9 inches long.

"Last year we walked around with a group at night with headlamps on, and there were dozens and dozens of them," McDaniel said. "The frogs were calling and it was just deafening."

It's a spectacle that most people never see. "There will be 300 frogs in one little pool, then you go back the next day and all you see are the eggs. It's all about timing," McDaniel said.

The best opportunities to see nighttime activity are in the early spring, just as the ground thaws and the first warm rain begins to fall.

Experienced amphibian fans venture out on their own, often driving hundreds of miles to a favorite site.

College student Taylor Swanson has made long treks through the Eastern Shore to find hundreds of amphibians active in a single, small pool. He's visited sites at 10 p.m. and 1 a.m., and collected photos and data for the Maryland Amphibian and Reptile Atlas.

"I really like to see how many different species I can find," Swanson said. He recommends coming prepared with a raincoat, boots and headlamp.

Some parks, nature centers and amphibian clubs offer organized field trips to see the migration to vernal pools on what is often called the "Big Night." Some set up protected road crossings for the critters and report what they see to experts who are collecting information on the region's amphibian populations.

Such field trips could be the best way to glimpse this often invisible universe. Vernal pools are shallow, and the life within them fragile. Removing animals or eggs from the pools is damaging and even illegal on public grounds. Trampling can harm species that are already threatened or endangered.

That makes public programs a great option, because they are guided by naturalists who can explain what you see and help avoid unintentional damage to the sensitive pools and the amphibians that visit them.

You can also lean about spring amphibians without a night-time journey. Parks and nature centers offer scores of daytime programs and are usually the best choice for children.

Field trips and programs usually start in early March with the Big Night, and continue for a few months while waves of frogs and salamanders shake off their winter sleep and launch the next generation.

"If you are driving between March and May, especially at night, watch the road. There could be amphibians all over it," Swanson said.

Hopping to go?

Check out this starter list of groups and parks that usually offer activities about spring frogs and salamanders — from volunteer programs, "frog strolls" and other daytime programs, to Big Night excursions.