OBSERVATIONS ON THE DISTRIBUTION, ECOLOGY, AND BEHAVIOR OF BATS ON THE GALAPAGOS-ISLANDS

The distribution of bats on five Galapagos islands was assessed using ultrasonic detectors that can identify the feeding calls of different bat species. Red bats (Lasiurus brachyotis) were present on Santa Cruz and San Cristobal. Hoary bats (L. cinereus) were present on Santa Cru z, San Cristobal, Isabela, Floreana and Santiago. Species identificati ons were confirmed by recordings of bat calls, observations of flying bats, and the capture of 21 red bats and three hoary bats. There was n o evidence of other species of bats on the Galapagos. Body size measur ements were similar to those of South American red (L. borealis) and h oary (L. c. villosissimus) bats. Species status of L. brachyotis is no t supported by morphological data. Both species were active in lowland and highland habitats, and foraging activity was high around street l ights. Radio telemetry was used to locate day roosts and the nightly a ctivity areas of four red bats in lowland areas of Santa Cruz. During the day, these bats roosted singly in the foliage of nine species of p lant. Nightly activity areas were 10 to 20 ha in size. The activity ar eas of individuals overlapped, and included their known day roost site s. Both bat species were apparently more active in lowland habitats du ring the cool garua season, and less active in lowland habitats during the hot season. Female red bats were more abundant in lowland habitat s during the cool season than were male red bats. Mesic, upland habita t may be critical to the survival of bats in the Galapagos.