When visitors experiment with different magnets they observe how the small needles react on their magnetic field. When there is no magnet near, or the magnet is too far away the needles will point along earth’s magnetic field. Close to a magnet the needles show the field of that specific magnet.
Compass needles are simply little magnets. When there are no other magnets nearby these needles are only pushed by the earth’s magnetic field. This field is relative weak as small permanent magnets quite simply disrupt the earth’s field.