RhymeZone: hagdon definitions

Definitions of hagdon:

noun: (regional, now rare) One of several species of sea birds of the genus Puffinus, especially, Ardenna gravis (syn. Puffinus gravis, Puffinus major), the great shearwater, and Puffinus stricklandi, the black hagdon or sooty shearwater.

(Definitions from Wiktionary)