The taxonomy of this dictionary (order, family, genus and species status and names) follows the IOC World Bird List (International Ornithological Congress) version 10.1 of January 2020 by Rasmussen and Donsker. Where different, the taxonomy according the the Handbook of the Birds of the World Alive (HBW) is also accounted for. Scientific names and English names used by other authorities, including eBird/Clements (2019), Howard and Moore (2018), British Birds (2020), and AOU (2019), are also mentioned, under “Synonym Latin“ and “English Synonym”, respectively.
Species vs. subspecies
Bird names are species names in principle. Subspecies considered as full species by some authorities or authors but as subspecies by others are also included as if they were species, for example Anser serrirostris. The variable status of such taxa is presented in the ‘Taxo’ line, where it is mentioned for example as ‘May be subspecies of A. fabalis’. The number of subspecies (following IOC and HBW) is presented as well; if there are no separate subspecies, the species is indicated as Monotypic.
The scientific genus name used as an entry is the one used in IOC World Bird List 10.1. Where an alternative name is sometimes used, for example in HBW, Clements Checklist 2019, Howard and Moore 2018, or was used in the past, this alternative is given below the preferred scientific (Latin) name. As an example, for Thalassarche cauta, the ‘Synonym Latin’ box gives ‘Diomedea cauta’. In special cases, two or even three (e.g. Linaria flavirostris) alternative genus names are included. All more or less well-known, including recent, alternative genus names can also be searched for.
The family name is given as the scientific (Latin) name (ending in –idae) and in 11 more languages (English, French, German, Dutch, Polish, Bulgarian, Lithuanian, Danish, Swedish, Welsh and Esperanto). The family distribution of the IOC World Bird List is followed. Alternative (previous) family names are given where appropriate. The families according to the IOC are presented in the multilingual Species Lists.
The higher taxonomic level: Order (eniding in -iforrmes) is not mentioned in the search results for species. It is mentioned, however, in the search results for families (after “Taxo”) and in the species lists (following IOC) after each family.