Surveys of Fruit Bats in Miag-ao
2022
May 24, 2022
Sulu Garden Foundation (SGF) has been regularly conducting bat population counts since September 2021. For the 2nd trimester of 2022, the count was conducted last May 19, 2022, with the Community Environment and Natural Resources Office (CENRO-Guimbal) and the Municipal Environment and Natural Resources Office (MENRO-Miag-ao).
Please click here to know the September 2021 bat count result:
Bats roosting on the branches of the acacia tree across the town plaza.
The Senior Science Officer of SGF, Ms. Norielle Diamante with Unit Head Wildlife Regulatory and Permitting Unit (WRPU)/Protected Area Management Biodiversity and Conservation Unit (PAMBCU)/Forester I, Ms. Jojie P. Gereza and Laborer/Contractual, Ms. Harlyn Mitra of CENRO-Guimbal; and MENRO-Miag-ao staff, Ms. Cindy Cabudlay, and Wildlife Enforcement Officers (WEO), Mr. John Paul Nonato and Mr. Jeyson Toledo conducted the bat count and started at the roosting trees inside the Miag-ao Santo Tomas de Villanueva Church.
Ms. Diamante with the CENRO and MENRO staff conducting bat count.
Visual count was used and the members of the bat count team each chose a roosting tree to count. Compared to the monitoring last January 2022, the bats went roosting at the church’s trees and municipal plaza again. The reason why they left their roosting sites at the church and plaza is still unknown, but it was suspected to be because of the damage left by Typhoon Odette that entered the Philippines last December 2021 and probably because of the lights from the Christmas decorations around the Municipal Plaza.
Please click here to know the January 2022 bat count result:
Based on January 2022 count, the number of roosting trees increased. From twenty-seven (27) trees with eleven (11) species, now to forty-eight (48) trees with eighteen (18) species. This means that there was an increase of the number of trees by 56.25% and the number of tree species by 61.11%. The bats did not return to roost on the agoho trees beside the church, but instead returned to roost at a big acacia tree and the mahogany tree at the corner of the church’s entrance gate. They also roosted at new trees around the municipality.
Common Island Flying fox roosting.
The eighteen (18) species of trees are Payhod/White Siris (Albizia procera), Tipolo (Artocarpus blancoi), Neem (Azidirachta indica), Bamboo (Bambusa spinosa), Agoho (Casuarina equisetifolia), Caimito (Chrysophyllum cainito), Coconut (Cocos nucifera), Balete (Ficus sp.), Gmelina (Gmelina arborea), Mango (Mangifera indica), Narra (Pterocarpus indicus), Acacia (Samanea saman), Santol (Sandoricum koetjape), Bubog (Sterculia foetida), Mahogany (Swietenia macrophylla), Sambag (Tamarindus indica), Talisay (Terminalia catappa), and Lanete (Wrightia pubescens).
Last January, there was a total of three thousand five hundred ninety-three (3,593) individual bats and the highest count in a tree was from the acacia tree with four hundred eighty-six (486) individuals and the least was from a mahogany tree with only two (2) counts. This May, the total population went up to five thousand nine hundred eighty-nine (5,989) individuals with one thousand three hundred fifty-three (1,353) counts on an acacia tree as the highest count per tree and the least count was eight (2) in both neem tree and bamboo.
Table 1. Distribution of the Bat Population among different trees around Miag-ao town plaza (as of May 2022).
TREE # | COUNT | TREE SPECIES | *TREE CONDITION RATING |
1 | 434 | Narra (Pterocarpus indicus) | 5 |
2 | 8 | Mahogany (Swietenia macrophylla) | 5 |
3 | 109 | Agoho (Casuarina equisetifolia) | 5 |
4 | 108 | Agoho (Casuarina equisetifolia) | 5 |
5 | 60 | Agoho (Casuarina equisetifolia) | 4 |
6 | 336 | Indian Mango (Mangifera indica) | 5 |
7 | 1,353 | Acacia (Samanea saman) | 1 |
8 | 118 | Mahogany (Swietenia macrophylla) | 4 |
9 | 249 | Indian Mango (Mangifera indica) | 4 |
10 | 8 | Neem (Azidirachta indica) | 5 |
11 | 40 | Mahogany (Swietenia macrophylla) | 4 |
12 | 43 | Mahogany (Swietenia macrophylla) | 3 |
13 | 179 | Narra (Pterocarpus indicus) | 1 |
14 | 168 | Caimito (Chrysophyllum cainito) | 2 |
15 | 195 | Sambag (Tamarindus indica) | 3 |
16 | 407 | Acacia (Samanea saman) | 2 |
17 | 90 | Balete (Ficus) | 4 |
18 | 46 | Mahogany (Swietenia macrophylla) | 5 |
19 | 136 | Gmelina (Gmelina arborea) | 5 |
20 | 111 | Gmelina (Gmelina arborea) | 4 |
21 | 44 | Caimito (Chrysophyllum cainito) | 4 |
22 | 167 | Mahogany (Swietenia macrophylla) | 4 |
23 | 124 | Mahogany (Swietenia macrophylla) | 4 |
24 | 140 | Mahogany (Swietenia macrophylla) | 4 |
25 | 43 | Lanete (Wrightia pubescens) | 5 |
26 | 25 | Caimito (Chrysophyllum cainito) | 4 |
27 | 81 | Santol (Sandoricum koetjape) | 3 |
28 | 27 | Caimito (Chrysophyllum cainito) | 3 |
29 | 116 | Caimito (Chrysophyllum cainito) | 2 |
30 | 202 | Mahogany (Swietenia macrophylla) | 2 |
31 | 22 | Coconut (Cocos nucifera) | 3 |
32 | 11 | Coconut (Cocos nucifera) | 3 |
33 | 60 | Mahogany (Swietenia macrophylla) | 5 |
34 | 30 | Mahogany (Swietenia macrophylla) | 5 |
35 | 12 | Coconut (Cocos nucifera) | 5 |
36 | 37 | Indian Mango (Mangifera indica) | 5 |
37 | 62 | Talisay (Terminalia catappa) | 5 |
38 | 125 | Caimito (Chrysophyllum cainito) | 5 |
39 | 109 | Tipolo (Artocarpus blancoi) | 5 |
40 | 70 | Payhod/White Siris (Albizia procera) | 5 |
41 | 89 | Bubog (Sterculia foetida) | 3 |
42 | 8 | Mahogany (Swietenia macrophylla) | 5 |
43 | 15 | Gmelina (Gmelina arborea) | 5 |
44 | 30 | Gmelina (Gmelina arborea) | 5 |
45 | 37 | Coconut (Cocos nucifera) | 5 |
46 | 8 | Bamboo (Bambusa spinosa) | 5 |
47 | 14 | Coconut (Cocos nucifera) | 5 |
48 | 83 | Acacia (Samanea saman) | 3 |
*Rating of the damage to the trees:
0 – The tree was cut down or broken
1 – 81% – 100% damage
2 – 61% – 80% damage
3 – 41% – 60% damage
4 – 21% – 40% damage
5 – 0% – 20% damage
Twelve (12) out of the forty-eight (48) roosting trees are mahogany trees, followed by six (6) caimito trees, five (5) coconut trees, four (4) gmelina, three (3) agoho, mango and acacia, two (2) narra, and one (1) of each remaining trees recorded and a bamboo grass.
The highest total average count per tree species is of the acacia trees with one thousand eight hundred forty-three (1,843) total count, followed by mahogany trees with nine hundred eighty-six (986) total count, mango trees with six hundred twenty-two (622) bats, narra trees with six hundred thirteen (613) bats, caimitos trees with five hundred five (505) bats, gmelina trees with two hundred ninety-two (292) bats, agoho trees with one hundred ninety-five (195) bats, tipolo tree with one hundred nine (109), coconut trees with ninety-six (96) bats, balete tree with ninety (90) bats, bubog tree with eighty-nine (89) bats, santol tree with eighty-one (81) bats, payhod tree with seventy (70) bats, talisay tree with sixty-two (62) bats, lanete tree with forty-three (43) bats and neem tree and bamboo grass both with only eight (8) bats.
The bat count population increase was probably because of some bats are travelling or transferring to nearby towns from town to town. It would be easier to track their activities using transmitters on them. More study is being done to understand better these bats’ activities and habits.
The next bat count will be on September 2022.
Written by: Senior Science Officer, Norielle Diamante (See profile)
