Homing pigeons can learn a navigational map by relying on the heterogeneous distribution of atmospheric odours in the environment. To test whether there might be a sensitive period for learning an olfactory–based navigational map, we maintained a group of young pigeons in an aviary screened from the winds until the age of three to four months post–fledging. Subsequently, the screens were removed and the pigeons were exposed to the winds and the environmental odours they carry for three months. One control group of pigeons was held in a similar aviary but exposed to the winds immediately upon fledging, while another control group of pigeons was allowed free–flight. When the pigeons from the three groups were released from two distant release sites at about six months of age post–fledging, the two control groups were found to be equally good at orientating and returning home, while the experimental pigeons held in the shielded aviary for the first three months post–fledging were unable to orientate homeward and they were generally unsuccessful in returning home. This result supports the hypothesis that environmental experience during the first three months post–fledging is critical for some aspect of navigational map learning and that navigational map learning displays sensitive period–like properties.