New bat and bird species found on Green Island

A comprehensive five-year study on Green Island has led to the documentation of 17 new bird species and five new bat species, according to the Ministry of Agriculture's Taiwan Biodiversity Research Institute. The research, conducted between 2020 and last year, aimed to survey the island's ecological resources.

The survey revealed that Green Island hosts at least 18 wild mammal species and 194 bird species. Among the newly identified species are raptors like the black eagle and upland buzzard, and five bat species: the yellow-necked sprite, oriental serotine, mountain noctule, oriental free-tailed bat, and the Asian bent-winged bat. Migratory birds constitute the majority of documented bird species, making up about 83%.

Institute Deputy Director Cheng Hsi-chi explained that the five new bat species were identified using ultrasonic detection techniques, as bats are typically too fast to capture, photograph, or observe directly. Taiwan is home to at least 37 bat species, and the institute is building a database of their ultrasonic calls for identification.

“

All five newly documented bat species were identified via ultrasonic detection techniques. None of the species were captured, seen or photographed, as bats usually fly too fast at night.

The study also noted a concerning decline in the Formosan flying fox population, with fewer than 10 remaining on the island. Researchers learned from local interviews that a single hunter reportedly captured over 100 flying foxes in the last century. Habitat destruction and human trapping are cited as primary reasons for their rarity.

Furthermore, invasive species such as common mynas, red-bellied squirrels, and Asian house shrews are threatening the island's native species. The common myna, in particular, has become dominant, marginalizing indigenous species like the crested myna. Cheng urged the public to refrain from bringing animals to Green Island, emphasizing the vulnerability of island ecosystems to invasive species.

“

Island ecosystems are more fragile and less stable than continental ones because of their limited land area. Species occupying the same ecological niche must compete for scarce resources on islands.