Opinions from D. A. Guthrie 1992
- 'Accipitridae belongs to Falconiformes'
- 'Aechmophorus belongs to Podicipedidae'
- 'Alauda alpestris belongs to Alauda' according to Linnaeus 1759
- 'Alauda alpestris is recombined as Eremophila alpestris'
- 'Alaudidae belongs to Passeriformes'
- 'Alca antiqua is recombined as Synthliboramphus antiquus'
- 'Alca antiqua belongs to Alca' according to Gmelin 1789
- 'Alcidae belongs to Charadriiformes'
- 'Anas caerulescens is recombined as Chen caerulescens'
- 'Anas canadensis is recombined as Branta canadensis'
- 'Anas fusca is recombined as Melanitta fusca'
- 'Anas perspicillata is recombined as Melanitta perspicillata'
- 'Anatidae belongs to Anseriformes'
- 'Anseriformes belongs to Aves'
- 'Ardea belongs to Ardeidae'
- 'Ardea herodias belongs to Ardea'
- 'Ardeidae belongs to Ciconiiformes'
- 'Asio belongs to Strigidae'
- 'Asio priscus belongs to Asio' according to Howard 1964
- 'Asio priscus belongs to Asio'
- 'Brachyramphus hypoleucus is recombined as Synthliboramphus hypoleucus'
- 'Brachyramphus hypoleucus belongs to Brachyramphus' according to Pallas 1811
- 'Branta belongs to Anatidae'
- 'Carbo penicillatus is recombined as Phalacrocorax penicillatus'
- 'Cepphus belongs to Alcidae'
- 'Cepphus columba belongs to Cepphus'
- 'Charadriiformes belongs to Aves'
- 'Charadrius belongs to Scolopacidae'
- 'Charadrius semipalmatus belongs to Charadrius' according to Bonaparte 1825
- 'Chen belongs to Anatidae'
- 'Chendytes belongs to Anatidae'
- 'Chendytes lawi belongs to Chendytes'
- 'Ciconiiformes belongs to Aves'
- 'Colymbus aalge is recombined as Uria aalge'
- 'Colymbus arcticus is recombined as Gavia arctica'
- 'Corvidae belongs to Passeriformes'
- 'Corvus belongs to Corvidae'
- 'Corvus corax belongs to Corvus'
- 'Cymochorea homochroa belongs to Cymochorea' according to Coues 1864
- 'Cymochorea homochroa is recombined as Oceanodroma homochroa'
- 'Diomedea belongs to Diomedeidae'
- 'Diomedea albatrus belongs to Diomedea'
- 'Diomedeidae belongs to Procellariiformes'
- 'Emberiza leucophrys is recombined as Zonotrichia leucophrys'
- 'Emberiza leucophrys belongs to Emberiza' according to Forster 1772
- 'Emberizidae belongs to Passeriformes'
- 'Eremophila belongs to Alaudidae'
- 'Falco jamaicensis is recombined as Buteo jamaicensis'
- 'Falco leucocephalus is recombined as Haliaeetus leucocephalus'
- 'Falco plancus is recombined as Polyborus plancus'
- 'Falco sparverius belongs to Falco'
- 'Falconidae belongs to Falconiformes'
- 'Falconiformes belongs to Aves'
- 'Fratercula belongs to Alcidae'
- 'Fringilla melodia is recombined as Melospiza melodia'
- 'Fulmarus belongs to Procellariidae'
- 'Gavia belongs to Gaviidae'
- 'Gaviidae belongs to Gaviiformes'
- 'Gaviiformes belongs to Aves'
- 'Gymnogyps belongs to Vulturidae'
- 'Haliaeetus belongs to Accipitridae'
- 'Hydrobatidae belongs to Procellariiformes'
- 'Laridae belongs to Charadriiformes'
- 'Larus belongs to Laridae'
- 'Larus californicus belongs to Larus'
- 'Larus californicus belongs to Larus' according to Lawrence 1854
- 'Melanitta belongs to Anatidae'
- 'Mergus belongs to Anatidae'
- 'Mergus serrator belongs to Mergus'
- 'Numenius chihi belongs to Numenius' according to Vieillot 1817
- 'Numenius chihi is recombined as Plegadis chihi'
- 'Passeriformes belongs to Aves'
- 'Pelecanidae belongs to Pelecaniformes'
- 'Pelecaniformes belongs to Aves'
- 'Pelecanus occidentalis belongs to Pelecanus' according to Linnaeus 1766
- 'Pelecanus occidentalis belongs to Pelecanus'
- 'Phalacrocoracidae belongs to Pelecaniformes'
- 'Phalacrocorax belongs to Phalacrocoracidae'
- 'Phalacrocorax pelagicus belongs to Phalacrocorax' according to Pellas 1811
- 'Phalacrocorax pelagicus belongs to Phalacrocorax'
- 'Plataleidae [misspelled as Plataliidae] belongs to Ciconiiformes'
- 'Plegadis belongs to Plataliidae'
- 'Podiceps belongs to Podicipedidae'
- 'Podiceps clarkii belongs to Podiceps' according to Lawrence 1858
- 'Podiceps clarkii is recombined as Aechmophorus clarkii'
- 'Podiceps nigricollis belongs to Podiceps' according to Brehm 1831
- 'Podiceps nigricollis belongs to Podiceps'
- 'Podiceps occidentalis is recombined as Aechmophorus occidentalis'
- 'Podicipedidae belongs to Podicipediformes'
- 'Podicipediformes belongs to Aves'
- 'Polyborus belongs to Falconidae'
- 'Polyborus prelutosus is recombined as Polyborus plancus prelutosus'
- 'Procellaria glacialis belongs to Procellaria' according to Linnaeus 1761
- 'Procellaria glacialis is recombined as Fulmarus glacialis'
- 'Procellaria grisea is recombined as Puffinus griseus'
- 'Procellariidae belongs to Procellariiformes'
- 'Procellariiformes belongs to Aves'
- 'Ptychoramphus belongs to Alcidae'
- 'Puffinus belongs to Procellariidae'
- 'Puffinus opisthomelas belongs to Puffinus' according to Coues 1864
- 'Puffinus opisthomelas belongs to Puffinus'
- 'Rissa belongs to Laridae'
- 'Rissa tridactyla belongs to Rissa'
- 'Scolopacidae belongs to Charadriiformes'
- 'Strigidae belongs to Strigiformes'
- 'Strigiformes belongs to Aves'
- 'Strix alba is recombined as Tyto alba'
- 'Synthliboramphus belongs to Alcidae'
- 'Tyto belongs to Strigiformes'
- 'Tytonidae belongs to Strigiformes'
- 'Uria belongs to Alcidae'
- 'Uria aleutica is recombined as Ptychoramphus aleuticus'
- 'Vultur californianus is recombined as Gymnogyps californianus'
- 'Vulturidae belongs to Falconiformes'
- 'Zonotrichia belongs to Emberizidae'