heres a good read, off a newsletter i recieve.
Pigeons wing it home on the sniff of a breeze
By Steve Connor
The mystery of how a homing pigeon is able to fly hundreds of kilometres to find its loft has been explained by scientists who have shown that the instinct relies on an acute sense of smell. A team of biologists found that young pigeons deprived of the chance of smelling the winds around their loft were never subsequently able to learn how to fly home. A study published this week in the Proceedings of the Royal Society of London revealed that an early ability to recognise the smells of local winds was crucial if a pigeon was ever to acquire its homing instincts. The first three months of a pigeon's life is crucial. Anna Gagliardo, the lead author of a team from the University of Pisa, said that learning to smell the wind allowed pigeons to associate odours with certain wind directions. "The outcome of this learning process is a map-like representation of the distribution of salient atmospheric odours in the region around the loft," said Gagliardo. The first three months of a pigeon's life is crucial. The researchers found that after three months of being kept in a screened aviary, deprived of wind, the pigeons never regained the homing instinct. Yet older birds, which had not been subjected to that sort of sensory deprivation, could relearn the homing instinct if they were moved to a new loft