BBC 20 Jun 13;
The plights of the world's threatened birds show the value of investing in conservation, according to campaigners.
One in eight of the world's birds is currently considered threatened.
A report by the Birdlife Partnership links continuing declines to deteriorating biodiversity, but it also highlights successfully protected species and habitats.
Conservationists suggest this shows how the estimated $80bn (£50bn) price tag of conserving nature is worthwhile.
Last year, scientists suggested it would cost about $5bn to reduce the extinction threat for all threatened wildlife, and up to $76bn to maintain a global network of protected areas.
"The total sums may sound large, but they are small in terms of government budgets, and they should be seen as investments, not bills," said Dr Stuart Butchart, Birdlife's head of science.
"Saving nature makes economic sense because of the payback in terms of services and benefits that people receive in return, from mitigating climate change to pollinating crops."
Through the Birdlife Partnership, 116 conservation groups from around the world pooled their research to create the State of the World's Birds report.
Birdlife first published an edition in 2004, when it called for urgent action to protect a third of the world's most threatened birds.
A further update in 2008 identified that common species are declining as a result of habitat loss.
The latest edition, launched in Ottawa, Canada, offers a complete overview of threats facing avian populations and the work being done to save them.
Data concerning the status of threatened birds over the past 25 years has shown steady and continuing declines toward extinction, with Pacific species and ocean-going seabirds declining the fastest.
Results from the publication also show that the biggest pressure on threatened birds comes from agriculture, followed by logging, invasive species and climate change.
Conservationists say our familiarity with birds, from both modern and historical studies, offers a route to understand the trends and patterns in our environment more broadly.
"Birds provide an accurate and easy-to-read environmental barometer that allows us to see clearly the pressures our current way of life are putting on the world's biodiversity," said Dr Leon Bennun, Birdlife's director of science, information and policy.
Although the report warns of a "planet in peril", there are also positive messages in the collected case studies from partner organisations that show the extent and effectiveness of conservation efforts.
For example, the UK-based RSPB and Birdlife International are working together to restore 100,000 hectares of Indonesian rainforest.
Birdlife partners are also establishing projects globally to protect endangered birds such as the African penguin, spoon-billed sandpiper and Azores bullfinch.
The report outlines six particular "success stories" - namely the Seychelles magpie robin, black robin, Mauritius parakeet, Rarotonga monarch, Asian crested ibis and Lear's macaw - where concerted efforts have brought species back from the brink of extinction.
"Effective nature conservation is affordable and it works. It's time to make it happen," said Dr Bennun.