We tested for differential habitat use by Pacific sheath-tailed bats (Emballonura semicaudata) in three major vegetation types on Aguiguan, Mariana Islands. Acoustic surveys of bat activity were conducted on a 370-m grid with 50 stations that covered the entire island. We controlled for a variety of extraneous factors through sampling design and use of a generalized linear model. Bat activity was significantly higher in native and nonnative forests than in non-forest habitats. There was no significant difference between activity levels in the two forest types. However, our sample size in non-native forest was limited to seven stations, thus the conclusion that non-native forest is an important habitat for the species should be viewed with caution. Our finding that E. semicaudata may be reliant on forest is critical because forests on Aguiguan are threatened by feral goats.