It is one of the most familiar and cherished signs of spring - the melodic chirping that heralds the end of the long winter months.

But the chorus that has filled the heavens for countless millennia is under threat, with a new report saying that at least 40% of avian species worldwide have declining populations.

Image: The State of the World's Birds

The State of the World’s Birds, a report by BirdLife International, says the scale of the problem is huge, yet there is a strong message of hope. Patricia Zurita, BirdLife’s chief executive, says the study “clearly demonstrates that solutions do exist and that significant, lasting success can be achieved”.

She adds that civil society, represented by wildlife groups and interested individuals, can help. “By harnessing local expertise within a global framework of best practice based on sound science, it is possible to achieve far-reaching and enduring impact.” she says.

An avian eco-economy

One of the main reasons for optimism is because watching birds is one of the world’s most popular pastimes. Around 60 million Americans, almost a fifth of the population, identify as birdwatchers, while in the UK, 23% of the population watches birds, the report says.

“Birdwatching is hugely important economically, constituting the largest ecotourism sector,” the authors note. “Collectively, the world’s national parks and nature reserves receive around 8 billion visits annually, many through avi-tourism, generating around $600 billion in revenue each year.”

However, human activities, including cutting down trees, are harmful to bird life. Logging is a key factor in the declining numbers of the most globally endangered species.

But the researchers highlight important measures being taken around the world. Measures, they say, that prove coordinated action can have a positive effect on biodiversity and bird life.

Image: The State of the World's Birds

Five ways to save the birds

1. Restore natural habitats

In the UK, wildlife charity RSPB is involved in a wetland restoration scheme on a scale never before attempted in Europe. Due to be completed in 2025, the project at Wallasea Island in southern England will have reinstated a total of 670 hectares of wetland.

Meanwhile, many saltpans across southern Europe and northern Africa, often constructed to separate seawater from salt for commercial purposes, have been abandoned or fallen into disuse. Now wildlife groups are working with local communities and salt producers to develop economic activities to ensure they remain profitable and can be used by migratory birds.

2. End deforestation and restoring forests

In partnership with the Worldwide Fund for Nature and the Wildlife Conservation Society, BirdLife is working on a scheme that will see one trillion trees re-grown, saved or be better protected by 2050.

For example, in the Harapan Rainforest in Indonesia, an innovative forest management licence has been introduced that has seen around 100,000 hectares being turned over to a consortium of wildlife groups that will manage the concession in the interests of wildlife and local sustainable development. The scheme has since been adopted across the country, BirdLife says.

3. Tackle illegal killing in the Mediterranean

Bird conservation groups in the Mediterranean are working to combat the illegal killing and taking of birds, many of them migratory species.

For instance, in Lebanon last year the Ministry of the Environment announced that a 2004 hunting law, which requires hunters to be licensed and bans electronic luring devices, would be fully implemented.

And the RSPB and BirdLife Cyprus have introduced covert surveillance to gather evidence on illegal bird trapping on the island. So far, 19 people have been secretly filmed illegally catching birds and successfully convicted.

4. Prevent seabirds being caught by fishermen

Established in 2005, BirdLife’s Albatross Task Force has targeted fisheries around the world to reduce the numbers of albatross and petrel being caught in fishing nets.

This has reduced the seabird bycatch typically by as much as 85% and often over 90%. Indeed, in South Africa, the number of albatross caught in hake nets was reduced by 99% over six years.

Meanwhile, in Chile, modifying the nets used in fleets using the purse-seine method reduced the bird catch by 98%, while trials in Peru have shown that lights on nets could further help to cut seabird deaths.

5. Captive breeding and reintroduction

Captive breeding and reintroduction is often the only choice for species that have been reduced to very small numbers. For instance, the island of Guam, in the western Pacific, lost almost all its local birds after the accidental introduction of brown tree snakes in the 1940s. The flightless Guam Rail was almost completely wiped out before the end of the 1980s, but a small number survived in captivity and in zoos.

Now, thanks to a breeding and reintroduction effort, the species is on the threshold of returning. They have been successfully introduced to Cocos Island, off the southern tip of Guam, and to Rota island 90km north of Guam.

Although it may be too early to say a self-sustaining wild population has been established, the signs are looking increasingly good.