We show a detailed magnetic force microscope study of the magnetic domain behavior in La1-xCaxMnO3 films under the influence of temperature, topographic sample defects and external magnetic field. At low temperatures, typically about 140 degrees below T-c = 245 K, domains were strongly coupled to each other, but could still be affected by thermal fluctuations. As we warmed the sample up, domains became highly mobile near T-c. Near T-c, sample scratches were able to capture nearby domains, whereas they did not affect domains when temperature is much lower than T-c. Above T-c all domains disappeared, with some of them disappearing earlier.