Background

The United Nations Conference on the Human Environment, held in Stockholm in 1972, made a number of recommendations regarding international treaties. One of these, Recommendation 32 of the Action Plan, was that governments should consider the need to enact international conventions and treaties in order to protect species which inhabit international waters or migrate from one territory to another. Recommendation 32 arose out of the realisation that failure to protect a migratory species throughout every stage of its migration can severely damage efforts to maintain or restore its population. The endangered Siberian crane (Grus leucogeranus), for example, is relatively secure in its Russian breeding sites and Indian wintering grounds, but its numbers have steadily declined in recent years primarily because it is hunted on its migratory route through Pakistan and Afghanistan. Many species of North American breeding birds are thought to be declining because of deforestation and the continuing use of DDT and other pesticides in their Central and South American wintering habitats. Passerines breeding in Northern Europe run a biannual gauntlet through the Mediterranean region where they are shot and trapped in their thousands as they make their way to and from their African wintering areas.