World Migratory Bird Day (May 11-12) wants to raise awareness about the dangers faced by migrating birds, which European citizens are more likely to see now that it's getting warmer. One example: spring has arrived and the swallows are back. After a long winter in warmer African climates, the birds with the blue, black and white feathers have flown back thousands of kilometers to breed in Europe.

"Migratory birds are programmed to reach their breeding grounds exactly when their prey is ready for the picking. When the trees are budding, there are many caterpillars for birds to feed their chicks in the nest," Fernando Spina explained in a DW interview.

Spina is scientific head of the Italian Institute for the Protection and Exploration of Wild Animals (ISTRA) in Bologna, and also chairman of the Scientific Council of the Convention on the Conservation of Migratory Species of Wild Animals (CMS), situated in Bonn, Germany.

Climate change a challenge for migratory birds

"Because of the global climate change, spring starts earlier and earlier in many parts of Europe," Spina says. "Researchers have shown that birds, like the European Pied Flycatcher, which spend winter south of the Sahara, now often return too late to catch the caterpillars. That makes it very difficult for them to raise their chicks."

Barn swallows try to adapt to the changing climate by arriving in Europe earlier. In order to do this, they reduce the distance they fly, the ornithologist says. "That means that the barn swallow spends the winter in a more northern part of Africa. That's a problem, because they land in drier areas with a lower humidity and find fewer insects to eat there."

Desertification is also making life harder for migratory birds. The Sahara is a growing barrier for them," Spina says.

A third problem is human development. While climate change is a major threat for migratory birds, loss of habitat through intensive agriculture is another. Vital marshlands are drained and used for fields or settlements. In some countries birds are hunted as well.

Conservation is a complicated business: Wind turbines that are erected to put a stop to pollution and rising global temperatures are endangering migratory birds in many areas, Bert Lenten, vice-president of the CMS, notes

Wildlife conservation needs international cooperation

"Migratory birds move thousands of kilometers between their winter quarters and their hatcheries," Lenten told DW. "That's why it's impossible to protect a species without being active in numerous countries. And that's why we aspire to international cooperation with the CMS agreement."

So far, 119 countries have joined the convention. Unfortunately, there isn't one central mechanism to control the agreed upon protection measures. "But in bringing countries and NGOs together, we can already achieve a lot," the Dutch expert said.

The Bonn-based organization does not only care for migratory birds, but for all migrating wild animal species on land, in the air and in the water. But while elephants or gorillas cross only one or two borders, the birds fly across multiple continents.

Promotion days win over young people to conservation

Since 2006, "World Migratory Bird Day" has been an annual event. Lenten is among its founding members:

"When bird flu reached Europe for the first time in 2005, that really hurt the birds' image. Many people saw them as messengers of death. We wanted to remind people that birds are actually something very positive."

Another special day of action- is that even worth the trouble? Yes, according to Lenten and mentions a visit to Botswana a year ago: "They had organized a lot of events with schools and enthusiastic young people. When you can awaken a positive attitude toward birds in young people, it's going to be easier to protect endangered species in the future."

For biodiversity and sustaining different ecosystems, migratory birds play a vital role, Fernando Spina says, "and that means also for us humans, too. Migratory birds are necessary for the pollination of many plants. They regulate the number of vermin. But they are also of huge cultural importance. Can you imagine spring without birds singing?"

This connection inspired Spina to organize a special event for this year's migratory birds weekend. Along with many bird excursions around the globe, the music aficionado has brought a choir from Bologna to Bonn to join spring song in the "capital of bird protection."

The San Rocco opera choir is giving a charity concert to benefit the Black Crowned Crane from Africa. The colorful bird is on the Red List of endangered species. "If we don't protect them, we risk losing one of Africa's and the world's greatest beauties," Spina says. An Italian choir singing in Germany to protect an African bird? Conservation, like migratory birds, really knows no borders.