The bird species of this dictionary are those occurring in the “Avionarctic” Region, which comprises the Palaearctic with the exception of its South-Eastern part, as well as the North-Eastern part of the Nearctic and Northern Africa including the Sahara. The Avionarctic area is roughly delineated by the red circle on the globe above.
Avionary has always used broader limits of the Western Palaearctic region, to include Iran and the Arabian peninsula, which are now included by others as well. The southern limit of the Avionarctic region is further to the South, running from the Cape Verde Islands in the West, roughly along the 15 °N latitude line to include most of Mauritania, and the northern arid parts of Mali to North Sudan, and then including the entire Arabian peninsula in the East. The eastern limit of the Central Palaearctic runs from the Arabian Sea east of Baluchistan and Afghanistan, where the region neighbours the Oriental (Indo-Malayan) region and then to the North-Eastern end of Siberia, to include the Central Asian republics as well as most of Sinkiang, Mongolia, Manchuria and Siberia. In the West, New England (US), Northern and Eastern Canada, Greenland, as well as the entire Arctic Ocean are covered. The area covered by Avionary is expanding step by step and will eventually cover the Holarctic and African regions.
Species that only have a single or even a disputed record in the region are also included, as well as some species without recorded occurrence (yet) in the region, but which are taxonomically or linguistically closely related to species from the region. For most families the entire Palearctic is already covered and some selected families are extended to the Holarctic, Holarctic plus Africa, or even the whole world. Details can be found in the Species Lists.
The regions of the world where a species regularly occurs are presented indicatively under the heading “Geo”, as follows:
WPal: Western Palaearctic within the conventional limits: Europe, Northern Africa (South to about 22 °N), Middle East
rWP: Rare to more regular visitors to the Western Palaearctic
CPal: Central Palaearctic: Western and Central Siberia, Turkestan, Iran, Afghanistan; when both WPal and EPal are covered, CPal is not mentioned
EPal: Eastern Palaearctic: Eastern Siberia, Mongolia, China except its South-East, Korea, Japan
Afr: Africa South of the Sahara (22°N)
Arab: Arabian peninsula; when the species occurs both in Afr and CPal, Arab is not added
Ori: Oriental (Indo-Malayan): from Pakistan to Indonesia and South-Eastern China
Aus: Australia and its neighbours
NAm: North America, including most of Middle America
SAm: South America
(S)AtlO: (Southern) Atlantic Ocean
(S)IndO: (Southern) Indian Ocean
(S)PacO: (Southern) Pacific Ocean
SOc: Southern Oceans, Antarctica