William Swainson FLS, FRS (8 October 1789 – 6 December 1855[1]), was an English ornithologist, malacologist, conchologist, entomologist, and artist.

A prolific collector of natural history specimens he produced an influential illustrated classification of birds based on the quinarian system that was then in fashion.

William, whose formal education was curtailed because of an impediment in his speech, joined the Liverpool Customs as a junior clerk at the age of 14.

[8][9] Swainson was involved in property management and natural history-related publications from 1841 to 1855, and forestry-related investigations in Tasmania, New South Wales, and Victoria from 1851 to 1853.

Subscribers received and paid for fascicles, small sections of the books, as they came out, so that the cash flow was constant and could be reinvested in the preparation of subsequent parts.

As book orders arrived, the monochrome lithographs were hand-coloured, according to colour reference images, known as 'pattern plates', which were produced by Swainson himself.

When in March 1822 Leach was forced to resign from the British Museum due to ill health, Swainson applied to replace him, but the post was given to John George Children.

Soon after his first marriage in 1823, Swainson visited Paris and formed friendships with Georges Cuvier, Étienne Geoffroy Saint-Hilaire, and other eminent French naturalists.

[10] In 1819, William Sharp Macleay had published his ideas of the Quinarian system of biological classification, and Swainson soon became a noted and outspoken proponent.

'for the great crime of burdening zoology with a false though much laboured theory which has thrown so much confusion into the subject of its classification and philosophical study'.

In 1851, Swainson sailed to Sydney and he took the post of Botanical Surveyor in 1852 with the Victoria Government, after being invited by the Lieutenant-Governor Charles La Trobe to study local trees.

There is a man who left this country with the character of a first rate naturalist (though with many eccentricities) and of a very first-rate Natural History artist and he goes to Australia and takes up the subject of Botany, of which he is as ignorant as a goose.

[20][21]He had studied the flora of New South Wales, Victoria and Tasmania before his return to New Zealand in 1854 to live at Fern Grove in the Hutt, where he died the following year.