Update....
Spoke to the farmer and he said that he does not want me to shoot duck. The reason being is the nature reserve have already started to complain and have gone to the extent of getting the police involved. According to them I have been shooting protected species. Any how, the farmer trusts me and to told them to politely to P**S off! But he doesn't want to escalate the situation even though he understands that it is not illigal. I Don't blame him, I would've loved to have been able to shoot duck but the fact that he took my side and never even questioned me on the subject meant a lot more.
I don't understand why birdwatchers would have such a big problem with people of our disposition, because at the end of the day we are both watching birds, the only difference is they use a pencil to mark their scores. LOL.