Features female and male Stitchbirds or Hihi (Notiomystis cincta). Nowadays these are highly endangered.
Buller said of this bird:
"...the Hihi has become the rarest of our existing native birds. To show how rapidly it has disappeared, I may mention that after my return to the colony, in 1874, I met with it only twice—the first time in a sunny glade in the Forty-mile Bush, near Eketahuna, and two years later in a strip of forest at Tarawera, midway between Napier and Taupo. "
Walter Buller KCMG (1838 - 1906) was a New Zealand lawyer and naturalist. His work, "A History of the Birds of New Zealand", was first published in 1873 and as an extended version in 1888. It is regarded as a classic of ornithology and New Zealand wildlife and describes several now extinct birds.
The artist who illustrated the birds was John Gerrard Keulemanns, regarded as one of the finest wildlife illustrators of all time.