The birds here look a little underexposed. The metering saw the much larger brighter background and exposed for the sky. That has caused the shadow areas (the underexposed birds) to be kind of muddy. The lack of contrast on the surface of the birds may make them look soft even if focus was good.
These birds are also awfully small in the frame. You do not have many pixels covering each bird (the closest one is less than 300 pixels from head to tail) so the camera cannot record much detail. Add to that you were shooting wide open with the 18-200 at full zoom. I agree with Randy that the D7000 is showing the limitations of this lens especially with a deep crop like this.