Surveys of Fruit Bats in Miag-ao
2024
November 2024
The bat population count survey for the year 2024 was conducted last November 28 in coordination with the Municipal Environment and Natural Resources Office (MENRO) – Miagao staff. The team was also accompanied by UP Visayas 4th year BS Computer Science students for documentation.
The total average bat count population for the year 2024 is at four thousand two hundred twenty (4,220) from a total of forty-three (43) recorded fruit bat roosting trees. The highest count is four hundred eleven (411) on a Mahogany (Swietenia macrophylla) tree while the least count is two (2) on a Niyog (Cocos nucifera) tree.
Similar to the previous bat count surveys conducted in the past years, visual count was used to determine the total average of bats per roosting tree. The number of bats per roosting tree varies per time and day. By 10 to 10:30 AM, the bats will move around with their guano (bat droppings), and transfer to other trees around the vicinity. Prior to the bat count, the team determined locations of roosting trees around the Miag-ao town center to map out areas for the survey.
Table 1. Distribution of the Bat Population among different trees around Miag-ao town center (as of November 2024)
|
Tree No. |
Local Tree Name |
Scientific Name |
Tree Damage Classification |
Average Bat Count |
|
1 |
Balete |
Ficus sp. |
2 |
396 |
|
2 |
Kaimito |
Chrysophyllum cainito |
4 |
20 |
|
3 |
Samalague |
Tamarindus indica |
4 |
286 |
|
4 |
Kaimito |
Chrysophyllum cainito |
4 |
125 |
|
5 |
Balete |
Ficus sp. |
2 |
18 |
|
6 |
Narra |
Pterocarpus indicus |
2 |
20 |
|
7 |
Balete |
Ficus sp. |
2 |
303 |
|
8 |
Kaimito |
Chrysophyllum cainito |
5 |
51 |
|
9 |
Kaimito |
Chrysophyllum cainito |
5 |
45 |
|
10 |
Mangga |
Mangifera indica |
4 |
7 |
|
11 |
Kaimito |
Chrysophyllum cainito |
3 |
58 |
|
12 |
Santol |
Sandoricum koetjape |
4 |
50 |
|
13 |
Kaimito |
Chrysophyllum cainito |
4 |
97 |
|
14 |
Niyog |
Cocos nucifera |
5 |
2 |
|
15 |
Niyog |
Cocos nucifera |
5 |
8 |
|
16 |
Lanete |
Wrightia pubescens |
3 |
20 |
|
17 |
Mahogany |
Swietenia macrophylla |
2 |
3 |
|
18 |
Mahogany |
Swietenia macrophylla |
3 |
147 |
|
19 |
Mangga |
Mangifera indica |
4 |
140 |
|
20 |
Tipolo |
Artocarpus blanco |
5 |
58 |
|
21 |
Kaimito |
Chrysophyllum cainito |
5 |
104 |
|
22 |
Mahogany |
Swietenia macrophylla |
5 |
13 |
|
23 |
Mahogany |
Swietenia macrophylla |
5 |
9 |
|
24 |
Mahogany |
Swietenia macrophylla |
5 |
12 |
|
25 |
Mahogany |
Swietenia macrophylla |
5 |
21 |
|
26 |
Talisay |
Terminalia catappa |
4 |
48 |
|
27 |
Kapok |
Ceiba pentandra |
3 |
207 |
|
28 |
Rain Tree |
Samanea saman |
4 |
22 |
|
29 |
Niyog |
Cocos nucifera |
5 |
5 |
|
30 |
Niyog |
Cocos nucifera |
5 |
15 |
|
31 |
Niyog |
Cocos nucifera |
5 |
34 |
|
32 |
Mango |
Mangifera indica |
5 |
273 |
|
33 |
Mahogany |
Swietenia macrophylla |
5 |
411 |
|
34 |
Mahogany |
Swietenia macrophylla |
5 |
70 |
|
35 |
Mahogany |
Swietenia macrophylla |
5 |
88 |
|
36 |
Mahogany |
Swietenia macrophylla |
5 |
52 |
|
37 |
Mahogany |
Swietenia macrophylla |
5 |
127 |
|
38 |
Tipolo |
Artocarpus blanco |
4 |
240 |
|
39 |
Rain Tree |
Samanea saman |
4 |
30 |
|
40 |
Mangga |
Mangifera indica |
5 |
226 |
|
41 |
Mahogany |
Swietenia macrophylla |
4 |
86 |
|
42 |
Mahogany |
Swietenia macrophylla |
5 |
35 |
|
43 |
Mahogany |
Swietenia macrophylla |
3 |
238 |
|
TOTAL |
4,220 |
|||
*Rating of the damage to the trees:
1 = 81% – 100% damage, 2 = 61% – 80% damage , 3 = 41% – 60% damage, 4 = 21% – 40% damage, and 5 = 0% – 20% damage
Thirteen various tree species were identified, namely Balete (Ficus sp.), Kaimito (Chrysophyllum cainito), Samalague (Tamarindus indica), Narra (Pterocarpus indicus), Mango (Mangifera indica), Santol (Sandoricum koetjape), Niyog (Cocos nucifera), Lanete (Wrightia pubescens), Mahogany (Swietenia macrophylla), Tipolo (Artocarpus blancoi), Talisay (Terminalia catappa), Kapok (Ceiba pentandra), and Rain Tree (Samanea saman). Fruit bats prefer trees with 0-20% damage with 48.8% bats roosting based on our findings on damage classification. As of November 2024, the fruit bats are more congested to the Western part of the town near the dead Bubog tree where the bats initially roosted. Refer to our interactive map for data visualization:
Fourteen (14) out of forty-three (43) roosting trees are Mahogany, followed by seven (7) Kaimito trees, five (5) Niyog trees, four (4) Mango trees, three (3) Balete trees, two (2) of Tipolo and Rain Trees, and one of each remaining trees. Based on the previous bat population count surveys, certain tree species are new roosting trees while some are no longer roosting trees by bats, such as the Bubog tree within the cemetery grounds due to severe damage.
Figure 1. Average Fruit Bat Distribution per Tree Species (November 2024)
The highest total average count per tree species is of the Samalague (Tamarindus indica) with two hundred eighty-six (286), followed by Balete trees with two hundred thirty-nine (239), Kapok tree with two hundred seven (207), Mango trees with one hundred sixty-two (162), Tipolo trees with one hundred forty-nine (149), Mahogany trees with ninety-four (94), Kaimito trees with seventy-one (71), Santol tree with fifty (50), Talisay tree with forty-eight (48), Acacia trees with twenty-six (20), both Narra and Lanete trees with twenty (20), and Niyog trees with thirteen (13).
Figure 2. Summarization of Total Average of Fruit Bat Population Count Survey throughout the years
The first bat population count survey last August 2021 had a count of seven thousand three hundred ninety-two (7,392). It was followed with totaled to three thousand five hundred ninety-three (3,593) from January 2022, then of the same year, it increased to five thousand nine hundred eighty-nine (5,989) in the month of May and subsequently decreased to five thousand three hundred fifty-five (5,355) on September. The following year, 2023, the bat population increased to six thousand five hundred thirty-one (6,531) on the January count and decreased a bit in May to six thousand one hundred one (6,101). After seventeen months, the November 2024 count, the bat population decreased to four thousand two hundred twenty (4,220).
The average bat count population decreased by 30.83% from May 2023 to November 2024. The bat roosting trees within the town plaza and Santos Tomas de Villanueva, commonly known as the Miagao Church were felled, hence there were no fruit bats roosting within the locale.
Special thanks to MENRO-Miagao Officer For. Isidro C. Mosura, Jr. and staff, Mr. John Paul Nonato, Mr. Joffrey Mondia, and Mr. Ariel Naldoza for their time and assistance.