He leased with his brother a large area in inland Patea, central North Island, for a sheep run.
[4][5] After schooling in England and Germany, Birch took a two-year course at the Royal Agricultural College in Cirencester.
He took a position in the Hawke's Bay area, with the runholder Ashton St Hill, by the Tukituki River.
[7] Azim, William's elder brother, had joined the 44th (East Essex) Regiment of Foot, becoming an ensign in 1855.
[1][7] The Birch brothers, Azim and William, leased a sheep run from Māori in the Kaimanawa-Oruamatua Block, after negotiations begun in 1867.
[13] Wool from the farm needed to be taken to Napier, an arduous journey for packhorses and mules carrying packs weighing 90 kilograms (200 lb) over rough ground, passing the Gentle Annie Summit near Tiniroto, and the Ngaruroro Gorge.
[16][17] This was a substantive investigation, one of the parties being Rēnata Kawepō with James Carroll as counsel; in contrast to a sketchy hearing held in 1875.
[19] The Homestead is a rare example of a house constructed from cob and has a Category I listing from Heritage New Zealand.
[2] On Birch's return to New Zealand, Erewhon Farm being accessible only by packhorse, he built a house, Stoneycroft, in Hastings, as the family home.