An experimental study regarding the noise properties of thin superconducting films of composition GdBa2Cu3O7-x on silicon membranes is reported. Noise measurements that include a determination of the Hooge parameter alpha(H) as a function of resistance have been carried out at temperatures 78 K < T< 300 K and frequency 1 Hz < f < 10 kHz for freshly prepared samples and after thermal cycling over a period of 0.5 years. The analyses indicates that noise within the superconducting transition region and frequency 10 < f < 200 Hz is determined by thermal fluctuation (phonon). The noise pattern at lower f is attributed primarily to flicker noise. This also holds for temperatures above and below the midpoint of the superconducting transition. At high frequency, resistance or Johnson noise is most pronounced. Microcrack formation, induced by thermal cycling, accounts for characteristic noise spikes at temperatures below the transition, primarily generated through electro-magnetic interference with environmental background perturbations. Electrical noise at T > 200 K most likely is assigned to an increasing interaction and charge fluctuations between the metallic overlayer and the semiconducting silicon membrane material beneath. The magnetron sputtered epitaxial GdBa2Cu3O7-x films consistently revealed Hooge parameters alpha(H) < 0.04 near the transition temperature, representing the smallest values ever reported for high T-c-films on silicon substrates. Based on these data, the achievable bolometric detectivity D* of superconducting transition edge microbolometers has been calculated. The model calculations fully confirm recent experimental data obtained for various degrees of thermal isolation.