On 13th November 2007, the Little Heron (Butorides striatus) has been under care for 11 days. All this time it was fed pieces of fish fillet, later pieces of whole fish. The bird was offered the pieces at the end of a pair of tweezers. It lunged at the pieces and immediately swallowed them, taking two to three pieces one after the other, although sometimes it had difficulties getting them down its throat.
Then it was transferred to a large cage (left). The sides of the cage needed to be lined with newspapers as it kept on trying to squeeze through the wires. Here, its behaviour changed. Every time it was fed, it took the first piece offered, refusing subsequent pieces, until an interval of time.
On the 13th evening I tried a strategy suggested by Victor Lee: “…As to learning to forage, what I used to do at Jurong BirdPark was to put birds like these inside a paddock with a small pool, etc. Put in live fish, tadpole, frogs, etc. and get them to work it out themselves. When they are hungry enough, they will forage and learn to pick up the live food. Hope this helps.”
So I purchased a bag of mixed guppies and mollies sold by aquarium shops for feeding predatory fishes kept by hobbyists. Two dishes, each with nine fish were placed inside the cage. One was a shallow dish (right), the other deeper.
The bird, not fed for the last six hours, simply stared at the fish in one dish, not moving a step. When I dropped a piece of the usual fish inside the dish together with the swimming fish, it took the piece and swallowed it after about ten minutes.
One of the live fish jumped out of the dish and died. This dead fish was placed on a spoon and left inside the cage. It was subsequently eaten.
Three hours later when I looked inside the cage, the shallow dish was devoid of fish. The bird had eaten all the eight remaining fish, leaving the fish inside the deeper dish uneaten. Overnight, the nine live fish in the deeper dish were also eaten save for a dead one floating in the water. This was removed from the dish and offered to the bird who immediately took it.
The images above show the sequence of the bird taking the fish from the deeper dish the following day.
When the guppies and mollies were all eaten, I got small goldfishes that were slightly larger. When offered in a dish of water, the bird went straight for one but the fish slipped out of its grasp before its head could be positioned for swallowing (below). It had to try again a few times before it succeeded in swallowing it. Subsequent attempts also had to be repeated.
After eating more than 30 goldfishes, the bird became well versed in handling the fish. Just before posting, I fed the remaining five and it took every one of them head first and swallowed them on the first attempt.
So the experiment is a success, thanks to Victor Lee. The bird should have a reasonable chance of survival when released into the wild.
“Give the bird a fish and you feed it for a day. Teach the bird to fish and you feed it for a lifetime.”
Victor Lee & YC Wee
(Images by YC Wee)