How do domestic pigeons know to return home even if they are transported in a closed box thousands of miles away? It is not because they have iron-rich neurons in their beaks. As a new European study published in the journal Nature shows , these metal-filled cells are not really neurons but white blood cells, more specifically macrophages, cells that are part of the immune system of birds and defend them from possible infections. Macrophages are also involved in recycling iron from red blood cells, but their mission goes no further. Therefore, the mystery about how pigeons detect magnetic fields and orient themselves remains .
? We already know which cells have nothing to do with the ability of birds to use the Earth's magnetic field to navigate and orient themselves ?, says David Keays, from the Institute of Molecular Pathology in Vienna (Austria). Now they just have to find where the magnetoreceptors are.
