Nice shots, Melanie. Your brown bird on the ground isn't a cowbird, I don't think. Mine that I have seen have a very distinct "hood" of a different color on their heads, and shorter necks.
The gulls on the roof might also be terns, depends upon the size - terns are smaller than gulls but that's the only difference I can think of. The black headed gulls and black headed terns look very similar.
