BULLETIN FLORIDA STATE MUSEUM


growth (1 station on Buena Vista). The mature forest, a minimum of 60 years old in all
places, had a completely closed canopy. Creeks were lined with rich shrub growth and
the creek beds received direct sunlight. Second-growth habitat at Buena Vista was ap-
proximately 20 years old and consisted of thick shrub growth and scattered small trees
that formed a discontinuous canopy.
 Each sampling station consisted of four or six 6 x 2 m mist nets and one or two
Tuttle harp traps (Tuttle 1974) set across permanent trails. Nets were set in pairs at
100 m intervals, with one of each pair at ground level (0-3 m) and the other at subcanopy
and lower canopy level (3-12 m). Early in the study nets were rigged in the canopy as
high as 25 m above ground, but use of these nets was soon discontinued because few
bats were captured in them, which seemed to reflect little flight activity in the canopy.
Harp traps were usually set at ground level in low, narrow tunnel-like passages created
by vegetation and trails. At a few stations where the vegetation permitted, harp traps
were rigged in subcanopy level "tunnels."
 Nets and traps were open from sunset to sunrise 67 times between 11 January and
31 December 1973. On 28 other nights during that period, sampling was conducted for
less than a full night. Total sampling during 1973 involved 4376 net-hours, 1213 trap-
hours, and 2324 captured bats.
 In 1971, a pilot study of 347 net-hours yielded 282 bats between 20 June and 18
August. In 1974 between 10 June and 17 July, 454 net-hours of additional sampling
yielded 278 bats. No harp traps were available during these times.


FIGURE 1.-Barro Colorado Island study area showing the 17 sampling stations.


Vol. 24, No. 4