BONACCORSO: A PANAMANIAN BAT COMMUNITY


dramatic population increases in the wet season. By contrast, small in-
sects (< 5 mm length) were abundant throughout the year.
 RESOURCE PARTITIONING
 Of 35 species of bats captured or sighted on BCI in 1973, 31 species
were captured in nets or traps and 4 other species were seen in flight or
at roosts. Noctilio leporinus, N. labialis, and Molossus molossus ap-
peared to be abundant but restricted their flight activities to habitats
not sampled-the shallow inlets of the lake (Noctilio) and above the
forest canopy (Molossus). The fourth species not captured, Vampyrum
spectrum, is a top carnivore and may be represented by very few in-
dividuals on the island. A pair of V. spectrum was netted by A. L.
Gardner and D. E. Wilson on 5 January 1973. In June 1973 I saw a
single animal flying at dawn.
 A first step at understanding how 35 species of bats partition food
resources on this small island can be made by dividing the fauna into
feeding guilds distinguished on the basis of two parameters-diet and
method or place of food procurement. This permits examination of
small complexes of species with similar foraging behaviors and diets. I
have divided the bats on BCI into nine feeding guilds with one to nine
species per guild. Justification for the placement of species into
specific feeding guilds will be provided in succeeding sections. For the
moment, the guilds are defined as follows:
 (1) "Canopy frugivores"-forage mostly on fruits that grow in the
 trees of the canopy and subcanopy level of the forest, above 3
 m from the ground.
 (2) "Groundstory frugivores"-forage mostly on fruits of
 shrubby groundstory plants, 0 to 3 m above ground level.
 (3) "Scavenging frugivores (or juicers)"-feed mostly on very soft
 ripe fruit, and/or over-ripe fruit.
 (4) "Nectar-pollen-fruit-insect omnivores"--forage for pollen and
 nectar when available during the dry season and for fruits and
 insects at other times.
 (5) "Sanguivores"-feed only on the blood of mammals and birds.
 (6) "Gleaning carnivores"-forage for small animals (arthropods
 or vertebrates) that are perching or moving on vegetation or on
 the ground.
 (7) "Slow-flying hawking insectivores"-forage for flying insects
 in small openings beneath or in the forest canopy or over
 streams.
 (8) "Fast-flying hawking insectivores"-forage for flying insects
 above the forest canopy or in very large open spaces (e.g.
 pastures).


1979