Brownie Gretchen Kellar, 7, gets a hand building a birdhouse from Wildlife Conservation Officer Randy Pilarcik on Saturday at the 17th annual BASF Earth Day Celebration at EDCO Park in Evans City. “Mobilize the Earth” was the theme of the celebration, which was held from 11 a.m. to 3 p.m. The event is meant to promote environmental awareness. Due to cold, and eventually rainy weather, Earth Day welcomed 150 to 200 visitors instead of the normal 500 to 600. Sarah Schade of BASF said most who braved the weather were repeat attenders. She said the most popular of the 23 exhibitors were the bluebird house-building exhibit, sponsored by the state Game Commission, and the BASF “Mr. Science” booth, in which children made slime.