Whether hiking rocky trails, skiing at snowy elevations or basking in spring sunshine, Coloradans are known for their outdoorsy tendencies. So when a bunch of down-to-earth, mountain-air breathing folks pitch in to clean up a park for an unofficial national environmental holiday, Earth Day, no one bats an eye.

Hundreds of Colorado Springs residents milled about Saturday at Garden of the Gods Park and neighboring Rockledge Ranch for the annual Earth Day celebration, meant to bring attention to protecting the environment, said Bret Tennis, program coordinator for the park.

About 170 volunteers picked up trash in large swaths of the 1,319-acre Colorado Springs park, the Seven Falls Indian Dancers performed several routines, kids petted llamas from Touch the Earth and others went on a nature walk.

Students from Academy School District 20's School in the Woods program were offering free tomato plants they had grown, and a handful of Air Force Academy cadets showed off the falcons they train.

Earth Day has been celebrated in the U.S. since April 1970. And though it not a federally recognized holiday, thousands of Americans observe the day, which promotes clean air, water and soil, according to the Environmental Protection Agency, which was established by President Richard Nixon and Congress also in 1970.

This year, Earth Day will be celebratedTuesday.

In recent years, the Earth Day celebration at Garden of the Gods, now in its 17th year, has attracted up to 4,000 people. But early in the day it appeared far fewer would show up this year, possibly kept away by the possiblity of rain clouds looming over the mountains Saturday morning, Tennis said.

Still, dozens of cleanup volunteers were undeterred.

"It's a very clean park. It's been hard to find stuff because it's so clean," said Vonnie Moden, who was out with her son Christian, an eighth-grader at Cheyenne Mountain Junior High. Christian was earning volunteer hours for the National Junior Honor Society.

The two found a flower pot, a sock and a Coke can.

"Mostly cigarette butts," Vonnie said.

"Mostly glass," said a boy named Adrian before bolting off into the woods, work gloves in hand.

"A lot of people don't know how Garden of the Gods is maintained," said Molly Mazel, a volunteer coordinator with the Rocky Mountain Field Institute, which had a crew out near the park's Kissing Camels rock formation on Saturday doing trail work.

"It's such a beautiful area," said Dan Heck, who led one of five volunteer groups from AAA Colorado picking up trash throughout the park. His group found a sleeping bag, hammer and beer bottles.

"It's amazing how they just throw things out here, ya know?" said Regina Hooper, who scraped her arm leaning into an oak shrub to snatch a small plastic whiskey bottle.

Some volunteers, like her daughter Bayley Hooper, 16, a junior involved in ROTC at Sand Creek High School, wonder why the Earth Day focus is only on one day of the year.

"If it's really that important shouldn't you do it every day?" she said.