One of the world's most mysterious birds is the slender-billed curlew (Numenius tenuirostris), an elegant wader. It breeds in bogs in the vast Siberian taiga and winters around the Mediterranean Sea. No one knows exactly where the birds breed or spend their winter. The last discovery of a nest dates back to 1924, and it has been several years since the last reliable sighting. Biologists estimate that only 50 birds remain today, and that their population is declining. Some even doubt that any individuals remain. If that were the case, the slender-billed curlew would be the first European bird to go extinct in 150 years. The reason why this is happening is as mysterious as the birds themselves. The most likely cause is hunting in the wintering grounds, but the details remain unknown. The species is not only listed on the world's notorious Red List of Endangered Species, but it also takes a prominent place on the appendix of an international treaty focusing specifically on waders and other water-dependent birds, such as gulls, swans, geese, ducks, and flamingos. This treaty is the African-Eurasian Waterbird Agreement (AEWA), concluded in 1995 and functioning under the Convention on Migratory Species of Wild Animals (CMS). Currently 51 countries, ranging from Ireland, Lithuania and Uzbekistan to Senegal, South Africa and Mauritius, have signed the Agreement.

Worldwide monitoring
AEWA is not only a political framework containing internationally agreed regulations. Most importantly, it aims to promote waterbird conservation in the field. One way of achieving this is to support research and monitoring of all waterbirds, including the slender-billed curlew. "We have received reports of sightings in Italy and Ukraine", says Sergey Dereliev, technical officer at AEWA. "Apparently the birds pass through these regions during their annual migration. If we can confirm these sightings through research, we can assert the need to protect these areas and hopefully convince governments to take action." In 2002, governments from around the world gathered in Johannesburg during the World Summit on Sustainable Development. The outcome of this meeting included the Millennium Development Goals, which aim to alleviate world poverty by 2015. In addition, governments adopted a target to 'significantly reduce the current rate of biodiversity loss by 2010', a goal set previously by the Convention on Biological Diversity. "This is of course a very ambitious target", says Dereliev, "but if you want to achieve anything at the global level, you do need to aim high." Progress has been slow, but the political will exists. Dereliev: "What we need now is more efficient cooperation between all the organisations and conventions that deal with biodiversity. And of course we need a lot more funds for implementing our strategies."

Research and monitoring underpin all international conservation strategies. Information on species' ecology is needed to understand why populations react to changes in certain ways, and to adjust conservation measures accordingly. Monitoring population trends helps to bring to light possible declines or recoveries. This is traditionally done through the International Waterbird Census, a huge worldwide effort to estimate population sizes and trends by counting birds. The Census is conducted each year in midwinter by more than 15,000 birdwatchers, mostly volunteers, in nearly 50 countries. The project has been coordinated by the organisation Wetlands International since 1967, and is the longest running and most extensive biodiversity monitoring scheme in the world. "Most is known about populations in Europe and North America", says Simon Delany, waterbird conservation officer at Wetlands International, "but developments are increasingly positive in Africa and Southeast Asia. Although there are still major gaps in our annual counts, for example in a crucial region like Egypt, we notice in general a growing interest in birdwatching and counting." AEWA, Wetlands International and a third organisation called BirdLife International, cooperate closely in training local people to participate in the annual bird counts. Special training offices have been established in Senegal and also in China. Delany believes that the accuracy of the trend analyses has increased over the years. "We have improved our overall coverage by looking at a larger number of sites. That makes our extrapolation to world populations more accurate. We now use advanced computer technologies to help us fill in the gaps." For the most recent version of the Census, totals of more than 20 million waterbirds of 230 species were counted. Many of these species show a continuous decline. Delany: "Reduction in available habitat is still a depressingly common story. Tundra-nesting species are in serious trouble, as are species that depend on wetlands. Many wetlands are being drained for agricultural purposes. Pollution remains a problem as well, and the hunting pressure in some regions is astonishing."

Communication is key
"Our challenge is to make our results more policy-relevant", Delany continues, "also for AEWA. We need to communicate our message in a more digestible and accessible way. The Nordic countries are an example of countries that do make direct use of the Census. They set their annual hunting bags based on our data. It is obvious that many countries don't. And the year 2010 is approaching rapidly. So far it doesn't look like the target is realistic, but we keep fighting." Communication is a priority for AEWA as well. Governments that have signed the Agreement committed themselves to take certain specific measures, such as banning the use of lead shot for waterbird hunting, but in practice these measures are often far from being implemented. "Training and awareness raising are incredibly important", says AEWA's Sergey Dereliev. "We are currently organising a series of workshops throughout Africa to promote sustainable hunting in wetlands. Next year we hope to do the same in the Middle East, and bring together authorities from the region." Another major activity is the establishment of a large-scale bird-ringing scheme in Africa. "Ringing birds for research purposes is a relatively common practice in South Africa, but other countries are still lagging behind. We hope to make local people in all of Africa enthusiastic for ringing and other aspects of bird research", says Dereliev. AEWA, which celebrates its tenth anniversary this year, contributes indirectly to achieving the 2010 target through its research, monitoring, training and awareness raising activities. It focuses on conservation more directly through so-called single-species action plans. Containing practical goals and guidelines, these action plans focus on individual species that are threatened, such as the sociable lapwing (Vanellus gregarius) and the dark-bellied brent goose (Branta bernicla bernicla). For the slender-billed curlew, a specific action plan was drafted together with CMS and BirdLife International. Fortunately, the waterbird story is not just one of continuous decline. Some species in the AEWA region have shown remarkable recoveries. Many species of geese are extending their breeding range, taking advantage of food availability in farmlands. Cormorants are doing increasingly well, although no one really knows why. Delany and Dereliev agree that international goodwill is increasing and worldwide efforts are encouraging. The 2010 target may be out of reach, and efforts might be too late for the slender-billed curlew, but a whirlwind of developments is taking place in conservation worldwide. For many waterbird species it will not be too late.

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