Convention on the Conservation of Migratory Species of Wild Animals (CMS / Bonn Convention)

The Convention on the Conservation of Migratory Species of Wild Animals, known as the Bonn Convention, was adopted at Bonn on 23 June 1979 and entered into force on 1 November 1983. Its Secretariat is provided by the United Nations Environment Programme, and the Government of the Federal Republic of Germany is the depositary, with the English, French, German, Russian and Spanish texts equally authentic.

The Preamble sets out a trusteeship view of nature. The Parties recognise wild animals as an irreplaceable part of the Earth's natural system that must be conserved for the good of mankind, affirm that each generation holds the earth's resources in trust for future generations and has an obligation to conserve and wisely use that legacy, and recognise the environmental, ecological, genetic, scientific, aesthetic, recreational, cultural, educational, social and economic value of wild animals. States are named as the protectors of the migratory species within their jurisdiction, and the Parties hold that conserving those species requires the concerted action of every state the species passes through during its life cycle.

Article I gives the Convention its definitions, and they carry real weight. A migratory species is a population that cyclically and predictably crosses national boundaries. Favourable conservation status is defined by four tests: the species maintains itself in the long term, its range is not shrinking, sufficient habitat exists and will continue to exist, and its distribution and abundance approach historic levels where that is feasible. Endangered means in danger of extinction across all or a significant part of the range, and taking is defined broadly to include hunting, fishing, capturing, harassing and deliberate killing.

Article II commits range states to act individually or cooperatively, with special attention to species in unfavourable conservation status, and it commits them to act before a species becomes endangered rather than only after. The operative machinery follows in Articles III to V. For Appendix I species, range states must endeavour to conserve and restore critical habitat, prevent or minimise obstacles to migration and control threatening factors including invasive species, and must prohibit taking, with narrow exceptions only for scientific purposes, for enhancing the species' survival, for traditional subsistence use or in extraordinary circumstances. Any exception has to be precise, limited in scope and reported to the Secretariat. Appendix II lists species for which range states should negotiate dedicated conservation agreements, and Article V says those agreements should aim at restoring or maintaining favourable conservation status across the whole of a species' range, covering periodic status review, coordinated management plans, joint research, habitat conservation and restoration, removal of migration obstacles, control of harmful substances, coordinated anti-poaching enforcement, emergency response and public awareness.

The institutional articles are procedural rather than ethical, and are summarised here for completeness. A Conference of the Parties meets at least every three years as the decision-making body, a Scientific Council of party-appointed experts advises on research, listing and conservation measures, and the Secretariat organises meetings and publishes information. Amendments to the Convention and to its Appendices each need a two-thirds majority. The Convention does not override existing treaties or the law of the sea and does not stop parties adopting stricter domestic protections. Disputes go first to negotiation and then, by mutual consent, to arbitration. General reservations are barred, though a party may enter a specific reservation on an individual species listing, which is the one place where a party can opt out of a particular obligation.