Hi, HGCheung.
It would be our human's common sense that big chases small. Like today, my wife and I saw about seven to eight hair-crested drones on the coral tree at Sai Kung Lion Club Nature Park. And they just kept chasing away the only one Orange-bellied Leafbird male away when they saw it (the orange-bellied leafbird kept came back!) But the one I posted here is the small fork-tailed chased away bigger than they are, Mrs Gould's Sunbird! Isn't it unbelievable!
Best
Eric
Second thought - those lions chase animals bigger than them. It is about how strong you are.
[ Last edited by tomatofamily at 14/03/2014 23:09 ]