Wild ducks (a male and a female) keep appearing on my pond and it seems obvious that they are looking for a new home.

They are very scared of us and the cat. Luckily the cat is terrified of them as well as they are bigger than her!

Can anyone give any advice as to what we should feed them or what to do? I don't want to disturb them unduly but I also don't want them disturbing or eating my fish. The koi carp would probably put up quite a fight but still! I have left them some small piles of wild bird food but am not sure if they have eaten it.

As they are a pair I wonder if they are lost or have been driven off from somewhere else and are looking to breed.

Any help from anyone who knows anything about ducks gladly accepted!