Nothing wrong with lots of horizons or backgrounds, and I honestly think that this picture doesn't need a foreground, or if it had one, it wouldn't be the main focus of the drawing... Maybe someone standing off to the side looking out at the ocean...
The birds really do seem like they're real... And the colors make for a really pretty sunset-time background... Purty!
i like the colors you used and how the birds look real and stuff :p..great job X_x