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Biodiversity & migratory birds PDF Print E-mail
Photo: © Dani-Jeske / Still Pictures

Migratory birds - indicators for wider biodiversity

Migratory birds are of great ecological and economic value as they are an integral part of the global biological diversity. Nearly half the world’s 10,000 bird species depend on forests, wetlands and grasslands - they are inhabitants of virtually all ecosystems of the world. They can be labeled some of the best indicators for the status and trends of wider biodiversity.

The biological variety of bird species

Photo: © Biosphoto / Seydoux Olivier / Still Pictures

Bird species are an excellent example for the enormous diversity created by Mother Nature on earth. Because they travel from ecosystem to ecosystem and because of their ability to fly, birds occupy a wide range of ecological positions, which normally would be out of reach for mammals for example.

These capabilities of birds, all possible because of flight, contribute to the relatively high number of bird species. While some are generalists, others are highly specialised in their habitat or food requirements. A good example is the bee-eater that lives on flying insects, predominantly honey bees from which it skillfully removes the poison sting. The prey is only of interest as long as it is in flight; once it has landed it will be ignored.

Birds breed on all seven continents, partially under extreme weather conditions. One example is the Snow Petrel, whose breeding colonies are found up to 440 km inland in Antarctica. The diversity in birds is, however, not only restricted to breeding areas or food requirements, it also includes their social behaviour, their appearance and their habitats. Some birds live territorially, others in small groups or huge flocks, most of them are terrestrial, whereas others only come ashore to breed. Some dive up to 500 metres, others grow as high as 2.7 m, like the ostrich, or stop at 5 cm like the Bee Hummingbird. 95 percent of all birds live monogamously, in order to provide biparental care for their hatchlings, some even mate for life. Some birds are perfectly camouflaged and almost invisible within their environment, others are as colourful as a carpet of flowers.

Although currently there are vast numbers of individual birds and a large number of different kind of birds, many species are now threatened with extinction. We know that at least 128 bird species became extinct during the past 500 years, 103 of them in the past 200 years. Currently about 12 percent of all bird species are considered to be globally threatened, that is, in danger of total extinction.

The sites migratory birds pass

{mosimage}Each year more than 800 species of migratory birds confront stiff winds, harsh weather and numerous predators to fly thousands of miles to a more suitable climate. In order to survive these long and exhausting journeys migratory birds depend on different stopover habitats where they can rest safely and find enough food. They need these critical stopover locations in the same way we need rest areas, petrol stations, restaurants and hotels when we take long trips. Strategically located patches of woods, wetlands, mudflats and beaches with adequate food and shelter ensure the survival of the species.

As development continues to remove such habitats from our landscape, it becomes increasingly difficult for exhausted migrants to find suitable areas to rest and refuel. As birds are some of the best indicators for the status and trends of wider biodiversity, they are important for monitoring changes in the environment.

Through their annual cycle, migratory birds cross many countries and continents, some of them from the tundra to the tropics, linking different ecosystems. Many sites - identified as the key sites for birds, so called Important Bird Areas (IBA) - host numerous other threatened species of plants and animals. Therefore areas important for birds represent hot spots for other biodiversity as well. By conserving them and their environment we ensure the conservation of biodiversity on a wider scale. Key biodiversity areas form the anchors of an efficient ecological network on a global scale. Like the IBAs, they can be identified based on the species they hold. Generally we have more data on the status and distribution of bird species than on other animals, which often is poor or patchy. This makes it particularly hard to identify the critical sites for these species.

Migratory birds as messengers

More than any other organisms, birds represent the concept of global biodiversity by spinning a web of interconnected and overlapping flyways that enfold the planet, illustrating its role as a global habitat. In this context the organisers hope to use WMBD to help spread the idea of migratory birds as messengers for the conservation of biodiversity worldwide.

For more information on the topic of biodiversity and migratory birds please take a look at the links we have provided for you in the links section.