Nearly half of the world's waterbird species are in decline, mostly due to rapid economic development and the effects of climate change, according to a global survey released today.

The fourth annual Waterbird Population Estimate found that 44 per cent of the 900 species globally have fallen in the past five years, while 34 per cent were stable, and 17 per cent rising.

Altogether, 12 families of birds have half or more of their global populations showing a decreasing trend, including storks, shoebills and plovers.

The worst decreases occurred in Asia, where 62 per cent of the waterbird populations had declined or become extinct.

That was followed by a 48 per cent decline in Africa, 45 per cent in Oceania, 42 per cent in South America, 41 per cent in Europe and 37 per cent in North America.

Simon Delany, a waterbird conservation officer for Netherlands-based Wetlands International which coordinated the survey, said the cause of the decline was a loss of wetlands either from economic and agriculture development rising temperatures which are blamed for worsening droughts and rising sea levels.

The survey represents about 50,000 hours of field work done in 100 countries.

"The most frequent known cause of population decrease is habitat destruction, often caused by unsustainable human activity," Delany told The Associated Press.

"The frantic pace of economic development is clearly having adverse impacts on the environment, including numbers and population trends of waterbirds," he said. — AP