At the age of nine, Wilson undertook his first expeditions at the Rock Creek Park in Washington, DC. He began to collect insects and he gained a passion for butterflies. He would capture them using nets made with brooms, coat hangers, and cheesecloth bags. Going on these expeditions led to Wilson's fascination with ants. He describes in his autobiography how one day he pulled the bark of a rotting tree away and discovered citronella ants underneath. The worker ants he found were "short, fat, brilliant yellow, and emitted a strong lemony odor". Wilson said the event left a "vivid and lasting impression on ". He also earned the Eagle Scout award and served as Nature Director of his Boy Scout summer camp. At the age of 18, intent on becoming an entomologist, he began by collecting flies, but the shortage of insect pins caused by World War II caused him to switch to ants, which could be stored in vials. With the encouragement of Marion R. Smith, a myrmecologist from the National Museum of Natural History in Washington, Wilson began a survey of all the ants of Alabama. This study led him to report the first colony of fire ants in the US, near the port of Mobile.