You won't see many godwits about at the moment as they're nearly all nesting in Alaska. But in September about 90,000 of them will fly back to New Zealand. You might spot one or two of them fossicking near the mouth of the Hutt or hundreds at the Manawatu River estuary.
A team of ornithologists recently reviewed all the information about our godwits' migratory flights and came up with some impressive figures. They say the birds make the longest non-stop endurance flights in the animal kingdom.
We New Zealanders like to think of godwits as our birds that spend part of the year in Alaska. But the Alaskans have a better claim to the species as the birds breed there but never here. After nesting, the godwits put on 60 to 70 per cent body weight while preparing for their southern migration. In August or September, all the American birds use the southernmost tip of Alaska as a springboard for their trip south. They wait until fair weather helps blow them southwards.
It takes the birds about eight days to fly the 11,700 kilometres non-stop to New Zealand, averaging about 60km per hour at a height of about 3km.
Every spring, big crowds of birdie people line the shore at Miranda, in the Firth of Thames, to greet the godwits when they arrive there, but Christchurch people give them the cutest welcome, ringing church bells. Until it collapsed in the quake the Christ Church Cathedral bells rang for 30 minutes. Post-quake, St Paul's Anglican Church in Papanui does the honours.
Next March, our godwits take off on their 10,000km non-stop flight to staging grounds on the coasts of China and Korea. After about a month feeding on those big mudflats the refuelled birds continue for 6000km to Alaska. The entire migratory return trip to and from Alaska totals 29,300km and takes about 20 days' flying time.
Thirteen ornithologists from Alaskan, Dutch, Australian, Auckland, Massey and Otago universities report the birds' migrations in the latest Journal of Avian Biology.
The Global Flying Network team base their findings on the movements of 12 godwits radio tagged in New Zealand and another five birds tagged in Alaska. Many more birds carried transmitters but either they or their batteries died en route.
The ornithologists are very worried about the godwits' only refuelling stop on the Asian mudflats. Almost 1.4 billion people live in the three countries surrounding the Yellow Sea and all claim the mudflats for industrial developments which threaten the godwits' feeding grounds. The scale of development in this region is massive with a 33km-long seawall enclosing over 30,000 hectares of tidal flats in Korea, which hosts about half a million shorebirds.
A few years ago, one radio-tagged godwit flew from New Zealand to Alaska and back, then decided to stay here permanently. The bird continues to live in retirement on the Miranda coast.
- © Fairfax NZ News