During the take-off run, when the indicated airspeed was about 40 knots, the pilot saw three wallabies run onto the strip in front of the aircraft. He rotated the aircraft in an attempt to avoid the animals but one of them collided with the tailplane. The pilot closed the throttle and landed the aircraft. The fencing around the aerodrome was inadequate to keep out native fauna and there was high vegetation close to the sides of the strip. The pilot stated that he had not previously seen wallabies within the boundaries of the aerodrome. This accident was not the subject of an on-site investigation.