because ネコ hate water and ducks 愛 water so the ducks and ネコ cant understand each other and the cat thinks he needs to put them out of their missery am i making sense? :)
Same reason southern 日本 hates Northern Japan, same reason the Capulets hate the Montegues, same reasion the British and the French hate each other, it is all because of some old grudge that nobody even remembers the reason for.
