The kagu long posed a puzzle to those who sought to classify it.  For a long time, it was believed to be a member of the Gruiformes, or crane-like birds.  More recent studies have placed the kagu within its own class,  Eurypygiformes, with the Central and South American sunbittern (second image).  The kagu is also believed to be closely related to the now-extinct New Zealand adzebills (lowest image).  This means that these birds likely came from a lineage that was dispersed with the splitting of the super-continent Gondwana.



  • Temporal range: Holocene
  • Fossil location: New Zealand (subfossil remains)
  • Known species: A. otidiformis, A. defossor 

The two Aptornis species are commonly known as the North Island Adzebill (A. otidiformis) and the South Island Adzebill (A. defossor). Both species were endemic to New Zealand until they were driven to extinction by hunting pressure from Polynesian settlers as well as predation of eggs and hatchlings by dogs and rats who had accompanied the humans to their new home. As a result, the birds were never encountered alive by European explorers. 

The North Island Adzebill was smaller than its South Island cousin, but both species were quite massive, about the size of small moa (with which they were initially confused upon discovery). The genus was omnivorous and may have fed on large invertebrates, lizards, tuataras and even small birds. The bird’s taxonomic placement is uncertain; it may belong in Gruiformes with the cranes and rails or in Eurypygiformes with the Kagu.   

(Info sources: x x) (Photo sources: x x) (Credit: Art by Dave Gunson)