'hedge banks')[1] could be described as the sixth inhabited island of the Isles of Scilly, but is usually included with St Agnes with which it is joined by a sandy tombolo known as "The Bar" when exposed at low tide.

Vegetation cover is mainly wind-pruned heath or dense bracken and bramble with a small area of coastal grassland formed over blown sand which has accumulated near the bar.

The five-year project aimed to keep the islands of St Agnes and Gugh free of the brown rat (Rattus norvegicus), in order to assist the survival of breeding sea birds.

The only menhir to be excavated on Scilly is the Old Man of Gugh, a 2.7 m (9 ft) tall standing stone which lies at the base of Kittern Hill, but there was no features or finds.

Kelp burning only produces 2–3 percent sodium carbonate, and during the 19th century more efficient commercial and industrial methods ended the practice locally.

In the 1920s, a retired surveyor and former consulting engineer of the Corporation of Wimbledon, William Hamlet Cooper (died 10 September 1932), formerly of Colchester, secured the lease of the island, built the two buildings that can be seen today and started a farm.

[7] In a 1925 letter to the Western Morning News he wrote of his attempts to control black-backed gulls (greater or lesser is not recorded), which included constant shooting and the destruction of nearly 2,000 eggs.

In 1924, none of his animals could graze on the northern part of the island during the nesting season due to attacks on his cattle and sheep, which included the loss of a valuable ram which never recovered from the injuries received.

The fire was put out by the staff of Major Dorrien-Smith and the farmhouse and farm buildings owned by Mr Theo Bond and his wife, the only inhabitants, were saved.

The VPA species are all present and occurring in suitable habitat except for small adder's-tongue (Ophioglossum azoricum) which has not been recorded on this site since 1986, however, the former site appears suitable for the species and is therefore recorded as favourable".The reasons for the unfavourable assessment is because there is too much ground cover of bramble (Rubus fruiticosus) and Pittosporum, and the heath on Kittern Hill is less interesting than on the rest of the island.

Amongst dense bracken is balm-leaved figwort (Scrophularia scorodonia), common here but not found elsewhere on the island and an unidentified yellow, cultivated rose.

Within these fields can be found viper's-bugloss (Echium vulgare), common melilot (Melilotus officinalis) and wild mignonette (Reseda lutea).

In the 1960s "the neck" was a closely cropped sward of grass, but after myxomatosis decimated the population of rabbits, the area became overgrown with bracken and bramble.

[16] The other mammals found on Gugh are feral cats, rabbit (Oryctolagus cuniculus) and possibly the house mouse (Mus musculus).

The survey showed that it was both feasible, and there are significant benefits, to remove the rats as they are preventing Manx shearwater and storm petrel from establishing on St Agnes and Gugh.

[13] In 2009 lesser black-backed gull bred on Gugh but with low chick productivity, and the small colony of kittiwake nested, but failed for at least the fourth year.

The five-year project aims to keep the islands of St Agnes and Gugh free of the brown rat (Rattus norvegicus), in order to assist the survival of breeding sea birds, which lost 25% of their populations between 1983 and 2006.