Newell's shearwater donkey-like braying call around the breeding areas. Townsend's shearwater ("P. auricularis") is very similar but has dark undertail-coverts, a shorter tail and a less sharp boundary between the black and white on the face. It was described as a new species "Puffinus newelli" in 1900 by the American ornithologist Henry Wetherbee Henshaw using specimens obtained by Brother Matthias Newell from residents of Maui. It was later included by some authors in the Manx shearwater ("Puffinus puffinus") as was Townsend's shearwater ("Puffinus auricularis"). Later, Townsends's shearwater was raised back to species status with Newell's shearwater as a subspecies of it. This
Audubon's shearwater homogeneous north-western Indian Ocean range, but not in the ecologically more diverse and by far larger Pacific range of "dichrous". These unresolved problems notwithstanding, this clade – possibly including the preceding one – has been proposed to constitute a separate species, the tropical shearwater or Baillon's shearwater, "Puffinus bailloni". These taxa could not be included in the most recent studies due to lack of material. The case of "gunax" seems fairly straightforward – as certainly as this can possibly be said in the absence of new data, it belongs to the "bailloni" clade either as a distinct subspecies, or, more