Figure 1.
A picture taken by infrared night observation showing a small fruit bat (in circle) licking sap from the shaved surface of a date palm tree without any intervention during the winter of 2010.
Figure 2.
Interventions to prevent bat drinking date palm sap during session two: 1. Bamboo skirt; 2. Dhoincha skirt; 3. Jute stick skirt; and 4. Polythene skirt covering the sap producing areas of the date palm tree.
In the later pictures, we can see sap harvester setting up an infrared camera.
Figure 3.
Identifying bats visiting date palm tree on a foggy night: a. 7∶08 PM, no fog, bats are easily identifiable; b. 3∶00 AM, fog blurs visibility but bats are somewhat identifiable; c. 3∶50 AM, fog starts to clear and bats appear clearly in the photos.
Each image shows bats in a circle, observation date, time, and ambient temperature when it was taken.
Table 1.
Frequencies of bat visits to different parts of date palm sap tree with and without interventions and comparison of sap in terms of appearance, volume and presence or absence of debris.
Figure 4.
Average number of bat visits per camera-night around the date palm tree (without intervention) during the date palm sap harvesting season in2009 and 2010.
Table 2.
Difference in debris presence, changes in volume of production and price of the sap harvested from date palm trees with and without skirt intervention in the 2009 and 2010 in Bangladesh.