Why a pigeon struts its stuff
Why do pigeons nod their heads every time they take a step?
FOR many years, ornithologists believed the synchronisation of a pigeon’s head bobbing with the movements of its feet was a biomechanical function, comparable to humans swinging their arms when walking. However, there is strong evidence this bobbing helps the bird’s vision.
In 1978, researchers at Queen’s University in Canada monitored pigeons on a treadmill in a Plexiglass box. They recorded the movement and slowed it down.
Their results, published in the Journal of Experimental Biology, overturned the key assumption: Pigeons aren’t bobbing their heads, but are pushing them forward then holding the pose and allowing the body to catch up.
In the so-called thrust phase, the head is pushed forward relative to the body by about 5cm. This is followed by a hold phase, during which the head is kept still. The human eye perceives this as a bob because the action is so rapid, taking place five to eight times a second as a pigeon is walking.
The researchers discovered that, when a pigeon’s visual surroundings remained static, the animal’s head doesn’t bob. Head thrusting helps pigeons to stabilise their view in a changing environment. Keeping the head still in space gives the bird a moment to process its surroundings to see potential food and predators.
Humans have an equivalent visual response known as Optokinetic nystagmus: rather than holding the head stationary, the eye fixes on objects in motion. These compensatory eye movements are used when walking, cycling and driving.
Andrew Symonds, London.
Does anyone still suffer from dropsy and lumbago?
LUMBAGO and dropsy still exist, but the terms are too imprecise for modern medicine.
Lumbago is acute or chronic pain in the lower back caused by muscle strain or a trapped nerve. The term comes from the Latin lumbus meaning hip or loin.
Dropsy referred to swelling caused by a build-up of fluid. This symptom of kidney disease or congestive heart failure affects the lower exterminates, abdomen or chest cavity.
Dropsy was often deadly, so physicians recommended drawing out the fluid to relieve the patient’s suffering and prolong life.
According to mid-19th century author Horatio Goodday, deaths from dropsy might be prevented by ‘good air; suitable clothing and shelter against excess of damp, cold and heat; cleanliness; proper food; exercise; rest; and the right observance of the Sabbath’.
Today we call it oedema from the Greek oidema, meaning to swell. This happens when small blood vessels leak fluid into nearby tissues.
Dr Ian Smith, Cambridge.
How many airports around the world are named after politicians or celebrities?
OUT of a total of 4,037, there are 351 scheduled commercial airports around the world named after a person. Most are politicians, royals or religious leaders. A growing number are named after a musician, actor, artist or sports star, while some honour aviators or industrialists.
The UK has two airports named for popular figures – George Best in Belfast and John Lennon in Liverpool.
The US has by far the most eponymous airports with 90. Most recent US Presidents are honoured: John F. Kennedy (twice, in New York and in Ashland, Wisconsin), George HW Bush, Bill (and Hillary) Clinton, and Ronald Reagan. We’re awaiting Obama and
Trump airports. Former Nevada senator Harry Reid has two airports named after him, one in Las Vegas and the other in Paradise, Nevada.
Sporting figures Arnold Palmer and Muhammad Ali, film stars Jimmy Stewart and John Wayne, comedians Will Rogers and Bob
Hope, musician Louis Armstrong, aviation pioneers Igor Sikorsky and William Edward Boeing, and flying aces Francis S Gabreski and Chuck Yeager have also given their names to airports.
Greece has Alexander the Great, Phillip II of Macedon, Aristotle and Hippocrates; Mongolia has Genghis Khan; France has Charles de Gaulle and Corsica has Napoleon Bonaparte; Albania has
Mother Teresa; Austria has Wolfgang Amadeus Mozart; Brazil has aviation pioneer Alberto SantosDumont and musician Antonio Carlos Jobim (of The Girl From
Ipanema fame); Hungary has Franz Liszt; Israel has David BenGurion; and there’s Ian Fleming airport in Jamaica and Cristiano Ronaldo in Madeira.
Palermo in Sicily commemorates Giovanni Falcone and Paolo Borsellino, two judges who fought the Mafia. Italy has Christopher Columbus, Marco Polo, Giuseppe Verdi, Caravaggio, Leonardo da Vinci and Guglielmo Marconi.
Just 16 international airports are named after women, including Indira Gandhi in Delhi, Queen Tamar of Georgia in Mestia, and actress Maria Montez, nicknamed the Dominican Queen of Technicolor, in Barahona.
Some have dropped off the list, notably Saddam International Airport, which is now Baghdad International Airport, and Hamid Karzai International Airport, now Kabul International airport.
Sandra Hayes, Chippenham, Wiltshire.
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