Tanja, very classy looking gull!
You could use a larger brush and mix your blue with a little white gouache to cover over the sky; it would make a smoother appearance.
total newb, but been reading; quick even soak with a sponge/large brush – tilted support aiming where the you want the dark – big brush BIG bead – quickly. if newbie, repeat very light washes for emotional ease while working large.
the bird is gorgeous, the greys oomphy and very satisfying, beautifully applied. good job!