The godwits f ly - and how
Stuff visual journalist Ross Giblin marvels at the godwits’ epic flight.
Alaska to Manawatu¯ – even in business class, the 11,000-kilometre flight might try the patience of an international traveller.
But the godwit or kuaka has to make the non-stop journey under its own steam – the longest flight of any migratory bird.
Every New Zealand spring, the godwit leaves its Alaskan breeding grounds, making the trip south in eight to 10 days. It goes to such extremes because of the food that abounds in New Zealand’s harbours and estuaries.
Before taking off, it eats large amounts for the long journey ahead. By the time of lift-off it measures about 55 per cent fat.
Because godwits don’t need to eat en route, they reduce the size of their digestive organs and increase the size of their breast muscles and heart, which will aid their flight.
The shape of their wings is also important. Non-migrating birds have short, broad wings that are suited to hovering and darting, whereas migratory birds such as godwits have long, narrow wings for sustained flight.
Massey University Associate Professor Phil Battley has been tracking the fortunes of the godwits which return to the Manawatu¯ Estuary every year.
In the early 1990s, about 500 made the estuary their home over the six months they are in New Zealand but that number has now dropped to 180.
Nationwide, there are an estimated 75,000 birds, down from 100,000 when they were counted 25 years ago.
‘‘That’s probably all about the conditions in the Yellow Sea, which are less favourable.
A recent study showed their food supply has been affected by reclamation.’’
While godwits fly south non-stop, on their way north in March, they re-fuel off the coasts of China and North Korea before returning to Alaska to breed.