Migratory birds at risk as habitats shrink

Godwits are able to travel 11,000km non-stop in less than nine days.
Godwits are able to travel 11,000km non-stop in less than nine days.PHOTO: NATIONAL PARKS BOARD

The Bar-tailed Godwit weighs only about 300g but its wings can take it to the moon.

Every year, these birds embark on an extraordinary journey from Alaska and Siberia to South-east Asia, New Zealand and Australia.

According to conservation group BirdLife International, a typical bar-tailed godwit of the baueri subspecies is believed to fly more than 460,000km during its lifespan - more than the distance between Earth and Moon. Studies have shown that the bird can travel 11,000km non-stop, in fewer than nine days.

To gear up for its epic journey, it fattens up until fat constitutes over half its body weight, while its gizzards and intestines shrink to almost nothing to reduce unneccessary body weight.

The bird uses the East Asian-Australasian Flyway - a major route stretching from Arctic Russia and Alaska to Australia and New Zealand. Millions of migratory birds use this aerial highway to fly south to escape harsh winters.

The birds, however, have been in decline over the years, in part due to developments along China's Yellow Sea coastline - a critical stop point for birds to recharge during their journey.

A study published in the Journal Of Applied Ecology this month, led by Professor Theunis Piersma of the Royal Netherlands Institute for Sea Research, shows the Bar-tailed Godwit is among three species of shorebirds which have suffered declines in their populations due to land reclamation around the Yellow Sea. Between 1990 and 2013, the area of shallow seas and intertidal flats along the Yellow Sea shrank by an average of 4 per cent per year.

"Shorebird populations worldwide are declining and their habitats are under stress from human factors, including land-use change, but the loss of habitat in the Yellow Sea is particularly alarming," said BirdLife International's head of communications Ade Long.

The Bar-tailed Godwit is not the only bird able to travel for long stretches. The Arctic Tern is known to migrate between the Arctic and the Antarctic, a round-trip distance of 30,000km to 40,000 km, according to BirdLife International.

A version of this article appeared in the print edition of The Straits Times on February 19, 2016, with the headline 'Migratory birds at risk as habitats shrink'. Subscribe