Four-digit Codes (German: Vierstelliger Code) is a concept based on the real life American Ornithological Society's "Alpha" codes. (For example, Bald Eagle is BAEA). A similar concept is Six-digit Codes for scientific names.

No two codes must be the same, or it gets confusing. No codes should have inappropriate language either.

Conflicting codes

  • Bluegill and Bluethroat: Bluethroat's code conflicted with Bluegill's. It has been changed to BLUG.
  • Jaguar and Jaguarundi: Since Jaguar comes first in the Anidex, it gets the code JAGU, while Jaguarundi gets the code JAGA.


Ndex MS Animal Class Type(s) Four-digit Six-digit
#031 031 Aardvark Mammals Ground AARD ORYAFE
#000 000 Aardwolf Mammals Ground AARW PROCRI
#047 047 Addax Mammals Rock ADDA ADDNAS
#035 035 African Clawed Frog Amphibians Water ACFR XENLAE
#087 087 African Fish-Eagle Birds Ice Flying AFEA ICTVOC
#052 052 American Ivory-billed Woodpecker Birds Ghost Flying AIBW CAMPRI
#005 American Kestrel American Kestrel Birds Fire Flying AMKE FALSPA
#077 077 American Toad Amphibians Ground Water AMTO ANAAME
#045 045 Andean Condor Birds Dark Flying ANCO VULGRY
#059 059 Arctic Fox Mammals Ice ARFO ALOLAG
#000 000 Asian Palm Civet Mammals Dark APCI PARHER
#024 024 Asiatic Black Bear Mammals Dark ABBE URSTHI
#000 000 Atlantic Puffin Birds Ice Flying ATPU FRAARC
#109 109 Baikal Seal Mammals Water Ice BASE PUASIB
#007 007 Bald Eagle Birds Ice Flying BAEA HALLEU
#049 049 Bali Starling Birds Fairy Flying BAST LEUROT
#011 011 Ball Python Reptiles Poison Ground BAOY PYTREG
#095 095 Bay-headed Tanager Birds Fighting Flying BYTA TANGYR
#125 125 Beluga Mammals Fairy Ice BELU DELLEU
#328 328b Black Jaguar Mammals Dark Grass BLJA PANONC
#013 013 Black Kite Birds Dark Flying BLKI MILMIG
#084 084 Black Mamba Reptiles Dark Poison BLMA DENPOL
#329 329b Black Panther Mammals Dark Electric BLPA PANPAR
#022 022a Black-coloured Grey Wolf Birds Dark Ghost BCGW CANLUP
#025 025 Black-footed Ferret Mammals Ground Dark BFFE MUSNIG
#082 082 Black-tailed Prairie Dog Mammals Ground BTPD CYNLUD
#008 Bluegill Bluegill Bony Fish Grass Water BLUG LEPMAC