First of all... does it meet the challenge? Yes... you have grain... I feel that maybe there is a bit too much here... but I actually kind of like it (which is unusual for me). Good choice to put this in black and white, or it wouldn't have worked with the grain.
On to specifics...
Great composition... my eyes go right to where they are supposed to and nice use of empty space as well, The darkness of the duck really draws you to that right corner, which is a good thing. And that mallard, leads you to the other duck, who by having his head turned and not looking off the frame manages to keep you in the image.
I agree with metatate I feel there is something funny about to happen... in a sort of Charlie Chaplin way. The pond is just too calm... and that mallard looks ready to end the duck's peaceful sleep :-D.
I like the fact that you didn't go for extreme contrast here... it's all slightly greyish and I think it works... I think this is really a picture that at first looks a bit dull, but as you look at it, it draws you in more, which is a good thing. Did you get more frames? Did anything funny happen next?