Abstract: The present invention provides a warning system to motorists to notify them of the presence of deer or other large animals along a roadside, such that the motorists can slow down and drive cautiously to avoid an accident with the deer. The system includes a plurality of posts installed along the roadside, with each post having a motion detector for sensing the presence of deer. Each motion detector is operatively connected to a light which is activated when a deer enters the sensing zone of the motion detector. The lights and motion detectors may be connected to a 120 volt power supply or to a battery which is coupled to a solar panel for recharging. The lights may be electrically connected in series such that all the lights are illuminated when one motion detector senses a deer. Each motion detector may also be connected to a sound generating device to deter the deer from the roadside. A light-sensitive photoelectric eye may also be provided such that the devices are functional only at night.