Level F-4 is the fourth level of Sardine Can Levels. To unlock this level, you must collect all feathers in Utopia.
Send the first sardine can off the topmost doughnut, having it settle between the three lollipops up there. This should clear a path southwest of where the can settled; more specifically, from the cookie southwest to the smaller doughnut. Toss another sardine can through this gap, having it settle as low as possible against the central pillar. If you are lucky enough to pop all pigs and get quite a bit of destruction, you'll get the feather.