Tree Squirrel dive bombed by Fork-tailed Drongo

Poor little Tree Squirrel snacking away on the road when, suddenly he's dive-bombed. Watch him carefully, see his heart racing. Not sure what's in it for the Drongo. Perhaps the bird thinks it's a game. There's more than enough food to go round in this location so it's hardly necessary to fight for resources. What do you think?
Captured in 4k Crop Mode at 50fps with Canon R7 & 100-500mm at about 300mm.