World Migratory Bird Day 2014

Each year on the second weekend in May, World Migratory Bird Day is celebrated to raise awareness about the need to protect these extraordinary animals around the world. In Europe, May also marks the return of countless migratory birds, like this stork, from warmer southern areas.

After spending the winter in sunny Africa, storks return to Europe to breed. But this spring storks arrived in Poland only to find sub-zero temperatures and snow. Since the bird is revered in Poland as a symbol of happiness and good luck, the idea of them freezing or starving to death motivated people across the country to organize emergency feeding programs.

Israel is a key stopover for many birds, especially the Great White Pelican. With an average body weight of six to eight kilograms (13-18 pounds) and a wing span of about three meters (9.8 feet), these pelicans are among the world's largest migratory birds. But climate change and the fishing industry threaten this bird, which was on a list of endangered species until 2009.

The Siberian White Crane is considered sacred to the people of Siberia's Arctic tundra. It makes the longest migration of any crane species, up to 10,000 miles round trip. Its numbers have declined drastically due to hunting and habitat degradation. The world population was estimated in 2010 at about 3,200 birds.

The Ljubljana marsh, a grassland reserve in central Slovenia, is the breeding ground for half of the country's bird species. It is a stopover point to some of the most threatened birds in Europe, including the Corncrake, a chestnut colored speckled migratory bird that travels from Africa to breed in the UK. It's known for a distinctive call which the male repeats about 10,000 times each night.

The Central European Blackcap is a medium-sized warbler mostly found in woodland and tall scrub. It spends its summers in Germany and Austria, and can now also be seen migrating to southern England instead of the Mediterranean. Some experts believe this is due to impact of climate change.

Migration can be a hazardous trip. Birds fly hundreds of miles, often covering large distances without rest. Exhaustion can make the birds less wary of potential dangers, such as colliding or faltering in flight. But they also face many other threats on the way such as predators, disease, lack of food, pollution, hunting and natural disasters.

Bulgaria and Romania recently signed a deal to set up three wetland areas along their joint Danube River border, protecting pelicans, herons, pygmy cormorants and other birds. The agreement will establish a zone in the east around Bulgaria's Lake Srebarna and Romania's Lake Calarasi; a second in the center, around Belene Island and Lake Suhaia; and a third in the west, around Ibisha Island.

The Wadden Sea, along the German and Dutch North Sea coasts, is considered one of the world's most important areas for migratory birds. Up to 6.1 million of them can be present at the same time, and an average of 10-12 million annually pass through the region. The site is one of the last remaining large-scale, intertidal ecosystems where natural processes function largely undisturbed.