Skip to content

Asian Openbills Took 30–62 Seconds to Handle Apple Snails in Direct Observations

Asian openbill carrying an apple snail
Research · Ecology

Asian openbills (Anastomus oscitans) feeding around ponds and canals at Mahidol University’s Salaya Campus in Thailand handled apple snails rapidly during observations from 1 to 5 March 2026. In six captures timed directly, the interval from picking up a snail to swallowing it was 30–62 seconds.

The birds located snails by probing or touch in shallow water, carried them a short distance onto the bank and used the lower bill to move the operculum—the hard plate that closes the shell opening—aside before extracting the soft body. The prey belonged to the introduced apple-snail genus Pomacea, which has become abundant in many urban waterways in Thailand.

Shells provided a second estimate of feeding activity

Along 176 metres of canal bank that groundskeepers cleared of shells each morning, the researchers counted 187 newly discarded shells over ten hours. If feeding had been continuous, that corresponds to about 18.7 snails per hour. The authors caution that more than one openbill may have contributed to the total even though they did not see several birds feeding there at the same time.

At a separate five-metre section used by a solitary bird, four new shells appeared in 25 minutes. These shell counts give a broader measure of activity than the six directly timed captures, but they are less precise because each shell cannot always be linked to a particular feeding event.

The snails were removed without crushing the shells

The discarded shells and opercula were intact. That differs from some earlier descriptions in which openbills crushed shells or left parts of the snail behind. In the Salaya observations, the birds appeared to extract the prey efficiently while leaving the shell largely undamaged.

The authors compare the observed feeding rates with the fastest previously reported for Asian openbills. They suggest that efficient use of introduced Pomacea snails helps the species exploit urban aquatic habitats and could contribute to natural suppression of invasive snails. The field note did not measure snail-population change, so this possible control effect remains a proposed ecological consequence rather than a demonstrated population-level result.

Sources and image credit

  1. Bateman, P. W., Gagnon, M. M., Thaweepworadej, P., Gilson, L. N., & Cobby, G. L. (2026). Foraging rates by Openbill Storks in urban Bangkok. Pacific Conservation Biology, 32(4), PC26024. https://doi.org/10.1071/PC26024Primary field note published 8 July 2026. Asian openbills were observed feeding on invasive apple snails at Mahidol University's Salaya Campus in Bangkok from 1–5 March 2026. Direct handling times were 30–62 seconds per snail (n=6), and discarded shells were used to estimate additional intake rates.

Image: Rison Thumboor / Wikimedia Commons / Flickr — Asian openbill carrying an apple snail in Thrissur, India, 13 May 2013; representative feeding image, not a bird from the Bangkok study; original uncropped file · CC BY 2.0 · Source

About this content: This story was produced with AI assistance within an editorial workflow developed by Wildlife Vagabond. Editorial responsibility remains with Wildlife Vagabond.How AI is used

Ecology

SPECIES IN THIS STORY

Species in this story

Asian Openbill Anastomus oscitans Explore species

Independent research and conservation news archive

Did you find this information useful?

Wildlife Vagabond is independently built and maintained. Voluntary support helps cover source verification, hosting and continued work on research and conservation news.

Support Wildlife Vagabond

The news archive will remain freely available.