Migratory species of wild animals are part of the world’s natural heritage. They form a significant portion of its biodiversity and genetic resources and play a unique role as indicators of ecological change (e.g. climate and pollution). In addition, they provide numerous ecosystem services for instance by dispersing seeds and pollinating plants. They are a source of food for other animals and humans. Many have spiritual and cultural significance and are key elements of ecotourism.

However, human activities threaten many species, and conservation efforts for migratory species are made more difficult because by their very nature as migratory animals, their behaviour means that they are frequently on the move. They depend on a range of often fragile habitats. Threats include barriers to migration (dams, power lines, wind farms, fences, roads, railways); habitat loss and degradation; by-catch; underwater noise; invasive alien species; wildlife disease; illegal hunting and fishing; pollution; marine debris; poisoning; desertification and climate change. As a result, many once common migratory species are becoming increasingly rare. There is a growing need to recognize the links between species and their habitats and, in particular, to protect breeding, wintering and stopover sites and migratory corridors. As migratory species pay no attention to jurisdictional boundaries, effective conservation depends on cooperation between countries.