Ulu Dedap in the Malaysian state of Perak is an extensive rice farming area about 90 minutes drive from where Dato’ Dr Amar-Singh HSS lives.
“I have often seen birds use human activities to aid in their foraging. On three occasions this morning [24th January 2013] I saw larger groups of raptors, herons, egrets (once in excess of 200) forage around tractors that were clearing fields that had been harvested (above). The birds were after the many rats that were killed [or stunned or even exposed] by the tractors cutting the stubble of the rice stalks [or were they poisoned?]. I am sure other small animals and larger insects were also consumed. It was easy picking but lots of conflict between birds present,” wrote Amar.
The above composite image shows two Eastern Cattle Egrets (Bubulcus coromandus) were the first on the scene. A Purple Heron (Ardea purpurea manilensis) spotted their activity and pounced in like a raptor with a loud cry and its hackles raised. The heron repositioned the rat head first for a better grip and moved some distance away before swallowing it.
When an Eastern Cattle Egret found a rat, the other egrets will give chase to try and get a bite. However Amar is unsure whether the egrets swallow the rat whole or piece meal, as most feeding activities took place some distance from the field.
A few crows were also involved in the action. As with most other birds, once it got hold of a rat, it would fly off to eat it elsewhere. Otherwise there would be a high chance of the prey being stolen either by the raptors or the herons. The above image shows a Large-billed Crow (Corvus macrorhynchos macrorhynchos) flying off with its prey.
At any one time there were 6-10 raptors circling the tractor in the field. Black Kites (Milvus migrans) and Brahminy Kite (Haliastur indus intermedius) predominated. The kites would swoop down to grab a dead rat often getting lots of straw in the process (above). An immature kite was photographed eating the rat on the wing (below). Note the lovely contrast difference of the under surface of the wings due to lighting.
According to Amar, Brahminy Kites were often harassed by the Black Kites who would pirate their food (kleptoparasitism) (below) or occasionally getting their own prey. At any one time there were six to seven Black Kites, a mixture of immature and adults, that would act as a group. “It was interesting that I did not see Brahminy Kites harass the Black Kites in return. Quite a number of juveniles/immature Brahminy Kites which caused some ID confusion with the Black Kites. Appreciate correction of any errors in my ID,” wrote Amar.
NB: “Kleptoparasitism or cleptoparasitism (literally, parasitism by theft) is a form of feeding in which one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food, including stored food. The term is also used to describe the stealing of nest material or other inanimate objects from one animal by another.” Wikipedia.