Parent: Alcidae (Auks)

└─ Aethia (Least auklets)

└─── Aethia cristatella (Crested auklet)

└─── Aethia psittacula (Parakeet auklet)

└─── Aethia pusilla (Least auklet)

└─── Aethia pygmaea (Whiskered auklet)