The term endemic, in the context of bird endemism, refers to any species found only in a specific area. There is no upper size limit for the geographical area. It would not be incorrect to refer to all bird species as endemic to Earth; in practice, however, the largest areas for which the term is in common use are countries (e.g. New Zealand endemics) or zoogeographical regions and subregions (West Indies endemics).
Birdlife International has defined the term restricted-range endemic as any species whose historical range is less than 50,000kmē.
Patterns of endemism
Almost all orders are represented on at least two continents. The orders with the most-restricted range are the mousebirds (Coliiformes), found only in sub-Saharan Africa and the tinamous, found only in South and Central America.
At the level of family, endemism is exhibited widely. Examples include:
- The Kagu, a monotypic family found only on New
Caledonia in the south Pacific Ocean
The Palmchat, another monotypic family, found only on the island of Hispaniola in the Caribbean
The kiwis, a family of five species found only in New Zealand
The todies, a family of five species found only on the Greater Antilles
The Hawaiian honeycreepers, a family found only on the Hawaian islands - see Endemism in the Hawaiian Islands and Endemic birds of Hawaii
Australia has many endemic families - see Endemic birds of Australia
Madagascar has a number of endemic families (plus others found only on Madagascar and nearby island groups) - see Endemic birds of Madagascar and western Indian Ocean islands
Endemic Bird Areas
Birdlife International has defined the concept of an Endemic Bird Area (EBA). This is a region of the world which contains two or more restricted range species.
To support this, they have also introduced the Secondary Area concept, for areas which contain one or more restricted-range species.
Publications in Bird Endemism
Birdlife International has produced two publications on endemism in birds:
- Putting biodiversity on the map: priority areas for global conservation C. J. Bibby, N. J. Collar, M. J. Crosby, M.F. Heath, Ch. Imboden, T. H. Johnson, A. J. Long, A. J. Stattersfield and S. J. Thirgood (1992) ISBN 0-946888-24-8
- Endemic Bird Areas of the World: Priorities for Biodiversity Conservation Alison J. Stattersfield, Michael J. Crosby, Adrian J. Long and David C. Wege (1998) ISBN 0-946888-33-7