In 1935, black drongos were introduced on Rota to control crop pests; decades later the aggressive birds spread to Guam and became a threat to native birds

In 1935, the Japanese South Seas Development Company made a decision that would have repercussions for Mariana Islands' ecosystems for nearly 100 years. In search of a natural method for controlling agricultural pests, they imported black drongos (Dicrurus macrocercus) from Taiwan to Rota.