How birds navigate during the long journeys they undertake in their annual migration is still a cause of debate among scientists. The main theories suggest that birds remember visual terrain maps, that they follow the Earth’s magnetic field or that they remember star maps of the sky. A new theory is that they do it by smell.

To prove the theory a scientist in New Zealand released 48 untrained homing pigeons 50 km from their home loft. In half of the birds they cut the trigeminal nerve (which is linked to the part of the brain involved in detecting magnetic fields) and in the other half they cut the nerves that carry olfactory signals to the brain. All but one of the birds deprived of their ability to detect magnetic fields made it home within 24 hours, indicating it was not that ability that helped them navigate. But of those deprived of their sense of smell only four made it back to the loft.

The scientists concluded that as part of their navigational abilities, pigeons use their acute sense of smell to “read” the landscape as a patchwork of odours.

The now disgraced 2006 Tour de France winner Floyd Landis blamed his failed drug test on alcohol consumption, a cortisone shot, dehydration and thyroid medication for his high levels of testosterone. While Landis may break the record for the most excuses, the funniest by far comes from another cyclist Adri van der Poel. The Dutch cyclist blamed his positive drug test for strychnine on a pigeon pie he had eaten prior to a race. Apparently his father-in- law, who raced pigeons, was giving his flock steroids to improve their performance. Van der Poel said he ingested the steroids second hand when he ate the pie consisting of some of his father-in-law’s culls