A tiny bird that weighs less than 100 grams has completed a 27,000 km round trip migration for the second time. This is the first time a wader has been tracked with a geolocator on its complete migration in successive years.
The bird in question was a ruddy turnstone (Arenaria interpres), a small wader weighing less than 100 grams which spends the (austral) summer months on many of the beaches around Australia. They are one of the family of waders that migrate huge distances to Siberia in Russia to breed. It was tracked by researchers from the Victorian Wader Study Group, a special interest group of Birds Australia [BirdLife Partner].
The bird had a one gram light sensor data logger (geolocator) attached to its leg. This device recorded where the bird was each morning and evening. In each year the device was attached to the bird in mid April on a beach at Flinders, Victoria, in southeast Australia. Researchers used these data logging devices over the last two years to find out the key stopover locations which are so important for the birds to refuel on their long journey.
“The data retrieved so far shows that the birds generally start their northward migration with an initial nonstop flight of around 7,600km in six days to Taiwan or adjacent regions” Dr Minton said. “There they refuel on the tidal flats before moving north to the Yellow Sea and northern China. They then make a flight of over 5,000kms to the breeding grounds in northern Siberia, arriving in the first week of June.
“One of the interesting findings is that after breeding, the return journey shows considerable variation, no two birds following the same route. Some return through Asia while an amazing alternate route has been demonstrated by these new results. This is a trans-Pacific route where the bird moves east to the Aleutian Islands off southwest Alaska before making the huge journey across the Pacific, stopping only once or twice before reaching Australia in early December.”
The first record of this flight was in 2009 when the bird spent nearly two months in the Aleutians before setting off southward over the Pacific Ocean and making a nonstop flight of 7,800kms to Kirabati before making the 5,000km trip back to Flinders, Victoria. In 2010 the same bird undertook a similar incredible journey, this time stopping off in the Marshall Islands and Vanuatu in the Pacific before returning to Australia.
Turnstones live up to 20 years and such a bird following this 27,000 km trans-Pacific route would have flown over 500,000 kilometres in its lifetime.
Scientists are still puzzling over why individual ruddy turnstones use such widely differing routes for their annual migrations. The study highlights the importance of key regions within the flyway. Scientists are concerned about the ability of these and similar birds to cope with the massive habitat changes occurring as a result of large reclamation and urban development projects.