Homing in on Animal Navigation
How do birds navigate vast oceans, correcting themselves when blown off-course? The inner compass possessed by some animals is an enigma that has absorbed Professor Michael Walker, Joint Director Ngā Pae o te Māramatanga, for many years. His breakthrough in extracting magnetite – the iron mineral also known as lodestone – from yellowfin tuna established a physical basis for this creature’s ability to detect the Earth’s magnetic field and was published in Science magazine in 1984. And, in November 2007, Science again gave extensive coverage to Michael’s work, saying his further research looked close to finally clinching magnetite’s crucial role in animal navigation.
The mineral had already been found in birds, but research recently completed by a team led by Dr Todd Dennis, Matt Rayner and Michael, in a collaboration between the School of Biological Sciences at the University of Auckland and Ngā Pae o te Māramatanga, demonstrates pigeons almost certainly use the magnetite in their natural global positioning system.
Geophysicist Joseph Kirschvink of the California Institute of Technology, who is himself one of the pioneers of research into magnetite, told Science: “If there is ever a Nobel Prize for magnetic field perception, Walker‘s name will be on it.”
From the Whakatōhea iwi, in the Bay of Plenty, Michael grew up aware of both European science and his Māori grandmother’s use of the maramataka, the lunar system for planting and fishing. A “hybrid mind,” he says, helped foster a fascination for different navigational methods – and an instinct, perhaps, for looking to nature for fresh clues on how things work.