Nonsuch Island is 60+ years into a groundbreaking rewilding effort, seeking to restore the islet to pre-colonial Bermudian habitat in order to facilitate the recovery of the endemic Bermuda Cahow.
The Cahow was thought to be extinct for 300+ years until the remarkable rediscovery of a few nesting pairs in the cliffs of Castle Harbour. The ground-nesting birds were wiped out on Nonsuch Island and all the larger Islands of Bermuda by the 1620s due to the introduction of predators – rats, cats, dogs, and hogs, and hunting by the early settlers.
A young David Wingate was part of the team that rediscovered the Cahow in 1951, and he would go on to dedicate his life to their recovery. Initially he equipped the rocky crevices where the Cahows were nesting with wooden baffles, which allowed the vulnerable population to nest without competition from aggressive white-tailed tropicbirds, which are also a protected species in Bermuda.
However, the Cahows were still vulnerable to being washed out by hurricane storm surges from the precarious cliffs. The idea to transform Nonsuch island into a ‘living museum’ – a restoration of Bermuda’s pre-colonial ecology, was an effort to allow Cahows, one of the rarest seabirds on the planet, a fighting chance of recovery.
Nonsuch Island had been used for grazing livestock from 1700-1860, as a yellow fever quarantine station in 1865, and as a reform school for delinquent boys from 1934-1948. When Wingate first began his rewilding efforts in 1963, the island was severely degraded – Bermuda’s cedar scale epidemic had decimated its cedar forest ten years before, and the remaining skeleton forest had been overtaken by invasive scrub, and grazed by a herd of feral goats.
Quick facts on Nonsuch rewilding:
Restoration took place in 3 phases: canopy, shrub layer, and finally micro-climate (consisting of shade-loving moss and ferns), which began 50 years into the project.
More than 6,000 native trees and shrubs were planted between 1963 and 1972, and 6,000 more have been planted since then, representing 63 different species of native plants.
Restoring the cedar forest was a priority, but a scale-resistant form had not yet evolved. The introduced casuarina tree was used as a stop-gap windbreak until the cedars could be replanted – but this was labour intensive; the trees required topping every two years to act as a windbreak, and their stubborn seedlings require removal from Nonsuch’s sheer cliffs.
More than 800 cedars were planted between 1974 and 1985, and by the late 1980s the forest was reaching maturity and beginning to self-seed.
Two artificial ponds were excavated to create saltwater and freshwater marsh habitats within the living museum in 1975 and 1992 – giving a full range of Bermudian pre-colonial habitats.
The island requires constant maintenance: as of May 2022, so far 4,800 invasive seedlings have been cleared. Over the entire island, 15,000 invasive seedlings a year are removed. This is not to mention the constant vigilance required to make sure toads, rats, ants, and other introduced species do not invade the island.
The rewilding effort has overcome several hurricanes, which have damaged the recovering forest and cahow nests.
As well as the cahow, the rewilding effort has aided the recovery of west Indian top shells and the endemic Bermuda skink.
This powerful conservation initiative has been extremely successful. As of 2022, the Cahow population has grown to a record number of 155 breeding pairs, up from 143 pairs in 2021. There are also a record number of chicks, 77, compared to the previous record of 73 chicks in 2019. In 1960, when the Cahow Recovery Project began, 18 pairs represented the entire population. As a large Cahow colony is established, the population of the Bermuda skink, a lizard thought to be semi-symbiotic with the cahow, is increasing as well – and it is the Nonsuch rewilding effort that has allowed the ancient relationship between these two critically endangered animals to be reconnected.
Whereas Bermuda’s mainland ecology has been forever changed by colonization, Nonsuch offers a window into the past, allowing the specialized island flora and fauna of Bermuda to grow and exist exactly as they evolved to do.