Officially Earth Day is April 22, but there's too much Earth to celebrate in one little day. The Pittsburgh region's Earth Day events are spread over a couple of weeks.

APRIL 16

• Chatham University, Shadyside, 6-8:30 p.m. Rachel Carson Spirit & Nature Conference. $25, $10 students, includes dinner.

• Observatory Hill, Perry Traditional Academy, 3-7 p.m. 412-322-1680.

April 19

• Carnegie Museum of Natural History, Oakland, noon-4 p.m. Activities including The Scoop on Poop. Free with museum admission.

• Pittsburgh Zoo & PPG Aquarium, Highland Park, 1-3 p.m. Party for the Planet activities included with general admission.

• Frick Environmental Center, Squirrel Hill, 10 a.m.-4 p.m. Bird walks, nature crafts, tree planting, garlic mustard pull and an owl encounter. 412-422-6538.

• McKeever Environmental Learning Center, Sandy Lake, 9 a.m.-noon. Volunteer work day. 724-376-1000.

• Raccoon Creek State Park, Hookstown, 10 a.m.- 3 p.m. Botany in a Day program exploring spring wildflowers. $5, 724-899-3611.

• Slippery Rock University, Robert A. Macoskey Center for Sustainable Systems Education and Research, 18th annual Earth Festival. Includes backyard birding, "green" cooking, workshops on biodiesel, wind and solar power with entertainment by the Zany Umbrella Circus, Well Strung bluegrass band and singer-songwriter Rick Bruening.

• Arlington Recreation Center, Arlington, 9 a.m.-5 p.m. 412-488-6111.

• Banksville Community Center, Banksville, 10 a.m.-1 p.m. 412-480-2757.

• Beechview United Presbyterian Church, Beechview, 9 a.m.-noon.

• Belmar Gardens, Oberlin and Mingo at the park, noon-3 p.m. 412-519-9313

• Bluff Park, Excel Kitchens, 9 a.m.--10 p.m. 412-396-1405.

• Crafton Heights, Westwood School, 10 a.m.-noon. 412-921-5927.

• East Allegheny, Cedar and East Ohio streets in the park, 10 a.m.-noon. 412-322-8056.

• East Liberty, Home Depot parking lot, 9 a.m.-noon, 412-381-1301.

• Frick Park Environmental Center, 2005 Beechwood Blvd., Squirrel Hill, 10 a.m.-4 p.m. Nature labyrinth, tree planting, invasive species removal, children's gardening, bird platform building, nature origami, community mural painting. 412-422-6538.

• Garfield, Modern Formations Gallery, 10 a.m.-2 p.m. 412-362-0274.

• Greenfield, Hammer Field parking lot, 8 a.m.-noon.

• Greenfield, Magee Field basketball courts, 8 a.m.-noon.

• Greenfield, Saline and Boundary streets, 8 a.m.-noon.

• Hazelwood, Gazebo at Second and Johnson, 8:30 a.m. 412-421-5648 ext. 11.

• Highland Park, Mellon and Jackson streets, 9 a.m.-noon. 412-441-8972.

• Homewood, United Apostolic Church Of God, 8:30 a.m.-noon. 412-370-4265.

• Lincoln Place, Old trailer park on Mifflin Road, 9 a.m. 412-464-1291.

• Mexican War Streets, Mechanic's Retreat Park, 10 a.m.-1 p.m. 412-400-0096.

• Morningside, Morningside VFW. 10 a.m.-1 p.m. 412-362-0132.

• Mount Washington, Lower Shaler Street Greenway, 9 a.m.-noon. 412-429-2400 ext. 210.

• Oakland, Sorrento's Pizza Roma, 10 a.m.-noon. 412-621-7863 ext. 10.

• Perry South, California Avenue and North Charles Street, 10 a.m.-1 p.m. 412-312-1019.

• Regent Square, parking lot below Center for Creative Play, 9:30 a.m.-11:30 a.m. 412-860-3522.

• Shadyside, 316 Spahr St., noon--4 p.m. 412-441-4385.

• South Side, 18th and Carson streets, 9 a.m. 412-431-4449.

• Spring Hill, Homer Street Firehouse, 9 a.m.-noon. 412-389-5946.

APRIL 20

• Hartwood Acres, Middle Road, Allison Park, Orienting with Map and Compass, 11 a.m.-2 p.m. $4 per map. 412-348-3156.

APRIL 23

• West Penn AAA's Great Battery Roundup, Critchlow Auto Body, 1798 Babcock Blvd., Shaler, 9 a.m.-4 p.m. $8 bounty paid for each collected car battery (up to 3) or an $8 donation will be made to the Western Pennsylvania Conservancy.

SATURDAY APRIL 26

• Pymatuning State Park, Jamestown, 8:30 a.m.-10 a.m., Spring Clean Up. 724-932-3142.

• Phipps Conservancy, Oakland, 11 a.m.-4 p.m., Programs on native plants, eco-art, local food sources, composting and recycling tips, and a book signing for "The Green Journal," written by Phipps' staff and published on Earth Day.

• National Aviary, North Side, 11 a.m.-1 p.m. Half-price admission for visitors who bring old phone books, newspapers, cereal boxes and empty cardboard containers, which will be recycled into enrichment toys for the birds. www.aviary.org.