Various types and colors of lines are used to prevent crop damage by tree sparrows, but their effectiveness against bird intrusions is unclear. A series of tests were conducted to ascertain whether the color and material of lines affected the entering frequency of tree sparrows. The tests were conducted with 10 tree sparrows in an aviary, using a rectangular frame (1 m long, 2 m wide, and 1 m high); the sparrows could enter only through the top of the frame. The lines were stretched in parallel at 30-cm intervals. The lines tested in 2016 were transparent fishing line, mat black wire, pink leveling string, black bird string, red/silver bird tape, gold/silver bird tape, and yellow bird string with silver mylar; in 2018, the lines used were white sewing machine thread, fluorescent red leveling string, white kite string, fluorescent yellow-green leveling string, and yellow bird string with silver mylar. The number of times the sparrows entered the frame was significantly lower in the line condition compared with the control (no lines) in both 2016 and 2018, regardless of line type. These results indicate that the presence of lines reduces the entering frequency of sparrows, but that the color and material of the lines do not have an effect.

In this study, 22 zoo-housed guinea pigs (14 castration, 8 females, average age of 47 ± 6 months) were used. We investigated the relationship between pausing behavior during following (frequency of behavior and number of individuals) at each location (area A, B, C and D) of guinea pigs and the number of visitors at each location (area A, B, C and D) and the personal characteristics (age and sex) of the guinea pigs. On the outbound trip, there was a significantly high negative correlation between the number of visitors in area A and the number of guinea pig pauses in area B (P < 0.01). On the return trip, there was a significantly high negative correlation between the number of visitors in area D and the number of guinea pig pauses in area C (P < 0.05). There was also a significantly high positive correlation between the number of visitors in area D and the number of guinea pig pauses in area D (P < 0.05). These results suggest that the pausing behavior of zoo-housed guinea pigs during events in which they perform following behavior may be influenced by the viewing location of visitors and the number of visitors, rather than the structure of the movement path of housed guinea pigs.