Average flight velocities were calculated from;

v = d/t (Eq. 1)

where v is average velocity, d is distance traveled and t is time. Average flight velocities were calculated from the data in Appendix A and are summarized in Tables 1, 2 and 3.

As a control the bats were initially flown down the hall without the presence of the harp trap. Ten of the fourteen bats flew to the end of the hallway (14.7m) at least once. In total, there were 20 flights to the end of the hallway. The velocity data are listed in Table 1. Two bats flew the entire length three times. Six bats flew it twice. Two bats flew it only once, and four bats never completed the entire length, but did fly shorter flights. There were many shorter flights. Where possible, velocities for these “abbreviated” flights were still calculated. Velocity data for the shorter flights is listed in Table 2.

A variety of “bat antics” were observed with and without the presence of the harp trap. When the trap was not being used it was stored against the wall. During the open hallway experiments, one bat landed on the trap wires. Another bat had a real “Kodak moment” when it landed on a bat poster on a bulletin board. Several bats landed on the ceiling. Even more bat antics emerged when experiments were run with the harp trap installed across the hallway. Despite very close tolerances between the wall and the trap, some bats managed to fly over and around the trap. Some flew into the bag without ever touching the wires. One bat bounced off the wires and landed some distance away on the floor, not in the trap bag. Some flew through the wires and were not trapped. (See Track 2 of Appendix C.) Some even landed on the trap wires and performed a “fireman’s pole routine” as they slid down the wires. (See Track 3 of Appendix C.) In one case a bat flew over the trap and landed in the bag on the opposite side of the trap. Another bat flew up and over the top of the trap and then dive-bombed between the two frames into the trap bag.

Thus, the results of experiments conducted with the harp trap in place have been categorized into four types –1) bat conventionally captured, 2) bat accidentally captured, 3) bat flew through the wires and 4) bat avoided capture. A capture was classified as conventional if the capture occurred in way that the trap was designed to operate (i.e., the bat hit the wires and fell into the bag). A capture was classified as accidental if the capture occurred because the bat flew into the bag without touching the wires or bounced off the walls into the bag.

Velocity data for 41 flights conducted with the harp trap positioned across the hallway is summarized in Table 3. The cells of the table have been color-coded to indicate the outcome of the flight—red for bats that were conventionally trapped, green for bats that were accidentally trapped, yellow for bats that flew through the trap and blue for bats that avoided the trap. Six flights resulted in conventional captures. Five flights resulted in accidental captures. In four of the flights the bats managed to fly through the wires. There was no indication, such as noise or vibrating wires, that the bats touched the wires in any of these four cases. In the remaining sixteen flights the bats avoided the trap, usually by turning around.

Weights were determined by weighing the bats. Photographs of the outstretched right wing were analyzed with digital software to determine wing areas. See Figure 7. Only the wing area was measured; the body and head were excluded. Wing loading was then calculated from;

WL= m/A (Eq. 2)

Where WL is the wing loading (g/cm2), m is the mass (g) and A is the wing area (cm2). These data are summarized in Table 4. Bats that were conventionally captured are marked in red. Those that flew through the trap are marked in yellow. And those that flew through the trap on one flight, but were conventionally captured on another flight, are marked in orange.


Table 3: Velocities for Bats in Presence of Harp Trap

Table 4: Weights, Wing Areas, and Wing Loading

(Figure 7: Determining Wing Area)