Rey Aguila a.k.a. stingRey documented a Grey Heron (Ardea cinerea) swallowing a larger than usual Common Snakehead (Channa striata) at Singapore’s Chinese Garden in Jurong (above). It was at 8.25 am in late December 2009. At first sight it would appear that the heron might not be able to totally swallow the snakehead. But swallow it did (below left).
The adult Grey Heron stands at a height of 90-100 cm. It has a slender crest, a distinctive long neck and thick yellowish bill. It feeds in shallow water, often waiting motionless for long periods for passing fish and frogs, as well as insects and anything else it can catch. It also takes small mammals and reptiles. It also stalks prey in slow motion movements.
The *Common Snakehead, also known as aruan, is commonly found in forested and rural streams, canals, drains, ponds and reservoits. It has great economic importance as the Chinese relish the flesh for its supposedly wound healing properties. However, the fish has to be killed just before cooking with a strong bash on the head. Adults are dark brown with faint black bands across its entire body. It takes about two years to reach a size of around 100 cm, but given the chance, it can grow to a metre long. The head reminds one of a snake’s head, thus the common name. [Please see Addendum below for the correct identification of the fish.]
The heron would have stabbed the fish, shaken or bashed it to render it lifeless before attempting to swallow it. As in most cases, the fish is swallowed head first, as otherwise, the spines or rays may be in the way. In this snakehead, spines are absent, making swallowing less of an ordeal. As posted earlier, the heron generally washes its catch before swallowing, but whether it did so with such a big catch as this was not reported. Usually, after swallowing its prey, the heron would drink a few times before moving off.
The bird has a powerful digestive system that would dissolves most of the fish except some of the more indigestible bones, etc. that would be compacted in the crop and eventually cast out as a pellet.
In Singapore the Grey Heron is a common resident, but it is nationally vulnerable due to loss of nesting sites and human disturbances.
Thanks to Marcus Ng, the fish has now been correctly identified as a walking catfish, possibly the introduced African species, Clarias gariepinus. We thank Kelvin PK Lim from the Raffles Museum of Biodiversity Research, National University of Singapore, for sharing his expertise.
Wang, L. K., M. Chan, Y. M. Chan, G. C. Tan & Y. C. Wee, 2009. Pellet casting by non-raptorial birds of Singapore. Nature in Singapore 2: 97-106.
This post is a cooperative effort between NaturePixels.org and BESG to bring the study of bird behaviour through photography to a wider audience.