“Many birds eat fish by swallowing them whole. Usually, birds will manipulate the fish to position the prey’s head to face its throat. Swallowing head-first is believed to ease ingestion and prevent sharp fins or spines from being caught in the throat. The attached images showed the process of a Common Kingfisher (Alcedo atthis) swallowing a small fish tail-first, which is unusual.
”The kingfisher first caught the fish by diving into the water and spearing it with its sharp bill. The upper mandible was observed to pierce the translucent body of the fish while the lower mandible helped hold onto the fish (above left). The fish was then bashed twice against the bird’s perch (above right).
“Next, the fish was held high above the bird’s head (above left). It was thought that the next sequence would be swallowing fish. Wrong! As the fish was still stuck in the bird’s mandible, the bird had to dislodge the fish first. How did the kingfisher do it? It did it by forward thrusting its head (and bill) to dislodge the fish (above right), then turning to its left and opening its mandibles to immediately swallow it. All this while, the the fish remained in the same position of its tail facing the bird’s throat.
“The actual swallowing was so fast that my camera, which is capable of 3 frames per second, failed to keep up and capture the action. Swallowing a fish by its tail first is a rather unusual method for birds but it is possible when the prey is small (as in this case). ”
Kwong Wai Chong
Singapore
24th December 2009
3 responses
The fish caught is a female guppy (Poecilia reticulata, http://www.fishbase.org/Summary/speciesSummary.php?id=3228), an introduced fish from the Americas, which does not have hard spines (only soft rays) on its fins, unlike other common prey fish such as tilapia. Perhaps the bird has some sense that this type of prey can be safely swallowed in any direction.
Lovely series on the little kingfisher. Happy new year.
Thanks for the clarification, Marcus.