Heinz Sielmann ( June 2 1917 in Rheydt , Germany â `` October 6 2006 in Munich ) was a world famous wildlife photographer , zoologist and documentary filmmaker . Heinz Sielmann ( June 2 , 1917 in Rheydt ( now MÃ nchengladbach ) , Germany â `` October 6 , 2006 in Munich ) was a world renowned wildlife photographer , zoologist and documentary filmmaker .