Under the terms of the Convention on the Conservation of Migratory Species of Wild Animals (CMS) 'migratory species' means the entire population or any geographically separate part of the population of any species or lower taxon of wild animals, a significant proportion of whose members cyclically and predictably cross one or more national jurisdictional boundaries.
Protecting migratory species also requires the protection of areas that are of importance for the migratory species which are situated in relation to migration routes, as wintering, staging, feeding, breeding or moulting areas.
The Convention on the Conservation of Migratory Species of Wild Animals, 1979 (Bonn Convention) came into force in 1983. The Convention aims to conserve those species of wild animals that migrate across or beyond national boundaries by developing and implementing cooperative agreements, prohibiting the taking of endangered species, conserving their habitats and controlling adverse impacts. Appendix I lists migratory species that are in danger of extinction throughout all or a significant part of their range. Parties which are range states are to prohibit the taking of such species (with limited scope for derogation), must try to conserve and, where feasible, restore their habitats, prevent or minimise impediments to their migration, and prevent, reduce or control influences that endanger them. Appendix II lists migratory species that have an unfavourable conservation status and which require international agreements for their conservation and management or would benefit from international cooperation. Parties are encouraged to take action to conclude agreements where this would benefit the Appendix II species concerned, and also to conclude agreements for any population or geographically separate part of the population of species or lower taxon of any wild animal, members of which periodically cross national boundaries. Specific agreements are concluded for the conservation of specific species between the relevant range states. In general, the geographic scope of such agreements is restricted to the migration area of the species concerned (the "Agreement Area").
The following agreements have been adopted to conserve specific groups of species: Agreement on the Conservation of Seals in the Wadden Sea, 1990; Agreement on the Conservation of Bats in Europe, 1991; Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas (ASCOBANS), 1992; Memorandum of Understanding concerning Conservation Measures for the Siberian Crane (Grus leucogeranus), 1993; Memorandum of Understanding concerning Conservation Measures for the Slender-Billed Curlew (Numensius tenuirostris), 1994; Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA), 1995; Agreement on the Conservation of Cetaceans of the Black Sea, the Mediterranean Sea and the Contiguous Atlantic Area (ACCOBAMS), 1996.
The decision-making body of the Convention is the Conference of the Parties, convened by the secretariat at intervals of no more than three years, unless the Conference decides otherwise. The Conference reviews the implementation of the Convention. The secretariat is provided by the UNEP and is located in Bonn in premises made available by the government of the Federal Republic of Germany. Parties to the Convention must inform the Conference of the Parties of the measures they are taking to implement the Convention and are also required to inform the secretariat of those species in the Appendices for which they consider themselves to be a range state. The Convention established a Scientific Council to provide advice on scientific matters. A Standing Committee was created by resolution of the First Meeting of the Conference of the Parties to fulfil various functions, such as providing policy and administrative guidance between meetings for the parties.