The pilot was conducting a sight-seeing flight and was returning to Jabiru at 6-700 ft above ground level. The pilot recalled seeing a bird just before it impacted the top of the windscreen. The bird did not enter the cockpit but the perspex was shattered. A large piece of windscreen attached to the compass electrical wires swung inwards and hit the pilot across the forehead, nose and mouth. He was wearing sunglasses at the time which may have protected his eyes from the debris. The pilot was able to control the aircraft normally although extra power was required to overcome the increased drag. The aircraft returned safely to the DEPARTURE airfield.