John Davies Enys, the second son of John Samuel Enys and his wife, Catherine Gilbert, was born on 11 October 1837 at Enys in Penryn, Cornwall, England, the family seat from the time of Edward I. His mother had, before her marriage, acted as compositor for a private press established by her father, Davies Gilbert, who was active in the Geological Society of Cornwall and a president of the Royal Society of London. Educated at Harrow School, John followed the interests of his mother's family. In the 1850s he attended lectures at the Geological Society of London, took walking tours in Britain and carefully recorded discoveries of ferns, wild-flowers and shells, establishing a pattern of life as an inveterate collector and keen amateur naturalist.
In 1861 Enys accompanied the Canterbury runholder J. B. A. Acland, who had been visiting England, on his return voyage to New Zealand; they arrived at Lyttelton on the Chrysolite on 27 July. Health problems may have been behind Enys's departure, but a strong incentive must have been the success of his cousin, Charles Tripp, who, in partnership with Acland, was pioneering high-country sheep farming in Canterbury.
After a year's cadetship on the Acland and Tripp stations Enys acquired a share in Tripp's Orari Gorge run for a few months in 1864. In October of that year, in partnership with his brother, Charles, who had come out to New Zealand in June, he took over the Castle Hill run, 2,300 feet above sea level in central Canterbury. The bachelor brothers lived with their much-loved cats in a pit-sawn timber cottage, Trelissick. They found high-country sheep management difficult and burdensome, and made an unsuccessful attempt to buy the Akitio station north of Castlepoint in northern Wairarapa, which they took the lease of in 1873. They were never successful farmers and survived only with substantial financial support from their family. The Enys brothers were well known for their hospitality, although the frequent absence of one or other (often in England) earned them the nickname 'the buckets in the well'.
John pursued his interest in natural science with enthusiasm and travelled extensively in search of specimens. From his first days in Canterbury he recorded observations of flora and fauna and soon became known as 'an enthusiastic, capable, and indefatigable naturalist.' His particular interest lay in ferns and mosses: he found the native tree-fern 'the most striking thing I have ever seen'. By 1866 he noted that he had collected 'all but 5 or 6 of the New Zealand ferns, which amount to about 140'; many of these he had discovered himself. He is better known, however, as one of the earliest authorities in New Zealand on moths and butterflies. In 1880 he edited and published privately a Catalogue of the butterflies of New Zealand, compiled by A. G. Butler but based on Enys's own collection. One specimen, Chrysophanus enysii, was named for him.
Castle Hill provided a rich store of bird, insect and plant life. Enys's name is commemorated in a number of botanical species found in the area, notably Ranunculus enysii. He found moa bones at Lake Grassmere nearby, and in 1868 uncovered beds of marine fossils of the Tertiary period buried in the striking limestone formations from which the property took its name. The area was also on a traditional Maori route from Canterbury to the West Coast and yielded artefacts for Enys's large collection. He deposited many specimens in the Canterbury Museum and in the Colonial Museum in Wellington, and sent others to Cornish museums and the British Museum. Experience of stone carving in his youth had given him an appreciation of the quality of Castle Hill stone and he donated stone for the pulpit and font in the Christchurch cathedral.
Akitio also yielded artefacts and fossils, and it was from here that Enys bagged some huia. His knowledge that the 'beautiful bird', 'differing from most birds in a marked manner', was nearing extinction was outweighed by his aspirations as a collector. He dispatched a mounted huia to his family at Enys, and also sent kiwi skins for making 'muffs and cuffs'. From his first days in Canterbury he had exchanged seeds of native flora for those from the garden in Cornwall, and as a member of the Canterbury Acclimatisation Society from its foundation in 1864 he was particularly involved in the establishment of trout in the area.
Scientists and amateur naturalists attracted to Castle Hill by Enys's discoveries included Thomas Cheeseman, Thomas Kirk, Leonard Cockayne and James Hector. He had visits from notable overseas travellers, among them his cousin the botanical artist Marianne North, Baron Anatole von Hügel of the British Museum, and a young naturalist with the French expedition observing the transit of Venus in 1874. A highlight of his own travels in New Zealand was his inclusion, at Hector's invitation, on a scientific expedition to Fiordland on the government vessel Luna in January 1873.
Enys developed a close friendship with Julius Haast, the provincial geologist, whom he had met soon after his arrival in Canterbury, and accompanied Haast on a number of expeditions. He was active in promoting the objects of the Philosophical Institute of Canterbury, and his particular contribution was to introduce in the Canterbury Provincial Council in November 1870 the ordinance which provided for the permanent establishment of the Canterbury Museum. Enys served on the original board of trustees and made generous gifts to the museum of moa bones, fossils and botanical specimens, as well as a fine collection of ores and minerals from Cornwall, antiquities from Egypt, and a collection of scientific publications bequeathed to him by his father.
A 'sense of public duty' motivated Enys's entry into public life. He was appointed a justice of the peace in December 1865 and represented Rakaia on the provincial council from 1870 to 1874. He was on the board of governors of the Canterbury Collegiate Union (the precursor of Canterbury College), and was a founding member and later chairman of the Upper Waimakariri Road Board. He was elected to the Selwyn County Council in 1878 and unsuccessfully contested the Coleridge seat in the parliamentary election of 1881.
John Enys published a number of papers in the Transactions and Proceedings of the New Zealand Institute. Others appeared in the Transactions of the Royal Geological Society of Cornwall and in the Quarterly Journal of the Geological Society of London, of which he was a fellow. Following his return to England in 1891 he was elected president of the Royal Institution of Cornwall in 1894.
In 1889 Charles Enys had become seriously ill, and died at Enys in January 1891. John leased Castle Hill and returned to Cornwall, and the run was finally sold in 1901. He succeeded to the family seat after the death of his elder brother, Francis, on 13 July 1906, and delighted in showing visitors the New Zealand garden he established there. John Enys never married. He died at Leeds, Yorkshire, on 7 November 1912. Mt Enys, the highest peak in the Craigieburn Range in Canterbury, where he made many notable discoveries, is a fitting recognition of Enys's contribution to the uncovering of New Zealand's natural resources.