Odors are known to be essential for navigation during homeward orientation and migration of some bird species. Yet little was known about their chemical composition. An international team has now identified volatile organic compounds that can be used for olfactory navigation by homing pigeons and proved the existence of suitable regional chemical gradients in the air on a landscape-scale in Tuscany.
Many bird species can find their way home even after being brought to remote or unfamiliar locations. Over 40 years of research on homing pigeons have shown that environmental odors play a crucial role in this process. Yet the chemical identity of these odors has remained a mystery. An international team of scientists from the Max Planck Institutes for Chemistry (Mainz) and of Animal Behavior (Radolfzell), and the Universities of Konstanz, Pisa and Mainz has now identified potential chemical navigational cues that could be used by homing pigeons. Based on the collected data, the researchers were also able to create regional olfactory maps for marine emissions, biogenic compounds, and anthropogenic mixed air and to establish the existence of regional navigable chemical gradients in the air.
During the scientific mission, which took place in 2017 and 2018 in the Italian region of Tuscany, the researchers measured a suite of airborne volatile organic compounds (VOCs) over a period of months at the pigeon’s home aviary. Some of these compounds are emitted by trees, the pine fragrance one smells during a walk in the forest. Other pungent natural emissions