A sea of children in white T-shirts gathered on the York Country Day School lawn to eat lunch on Friday. They laughed and played like any group of kids.

But it wasn't until a few minutes later that it became clear what their purpose was: to celebrate natural resources, Earth Day and the efforts of one of their own.

After lunch, the children gathered in the school's gymnasium. Their T-shirts read "Every Drop Counts," referring to water. In the front row, a few people of all ages wore lime green shirts.

The shirts read "Mateo's

Litter Critters" and had a logo with a blue lizard on the back.

Mateo's mission: Mateo Maldonado, 7, sat quiet and unassuming in the front row.

The first-grader and his family look for areas to clean around York City. On March 10, Mateo collected 47 bags of trash from just one area. Since that time, he organized Mateo's Litter Critters, a volunteer initiative, and is planning additional cleanups in the city.

Mayor Kim Bracey, smiling, stepped in front of the crowd. She called up shy Mateo and gave him a hug, as well as a certificate of recognition for his community service.

"I don't know how you did that," she said, beaming with joy. "We just would like other people to follow his example."

A wave of standing ovations soon overtook the gymnasium.

Future efforts: When asked why he cleans up litter, Mateo was humble.

"Because it's a good thing," he said, adding litter "doesn't look good and it hurts animals."

The York City boy has held a couple small cleanups so far this year, filling 78 garbage bags in total.

Her son's desire to clean up litter started in pre-K, his mom, Meranda Rodenhaber said. Once at a football game, he wouldn't let his family leave until all the trash was picked up.

"We're learning with this too," she said.

Mateo's Litter Critters is just starting out, but it keeps the safety of its volunteers as a top priority, said Chris Maldonado, Mateo's dad. After all, the lime green shirts are pretty easy to spot.

Another concern, he added, is where to dispose of all the trash as the event grows bigger and bigger. But for now, the project continues to grow.

"We got a lot of positive feedback. It's really getting off the ground here," he said.

Mateo's next big project on May 18 will clean up the city's Farquhar Park. His parents are proud of his values.

"He just does it thinking it's the right thing to do," his dad said. "Because it's so genuine, it's just awesome."

Email mateoslittercritters@comcast.net for ways to help the cause.

-- Reach Mollie Durkin at mdurkin@yorkdispatch.com.