Vintage bird art showing adult and young Gould's Harriers (Circus gouldi). These are now known as Swamp Harriers or Kahu (Circus approximans).
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.