The lighthouse building is listed as a building of Architectural/Historic interest. The island lies at the mouth of the Firth of Forth, 5 miles from the Fife mainland and 11 miles from East Lothian. The island's coastline is rocky; its surface covers 140 acres and slopes gradually from vertical 150ft cliffs on the west side to sea level on the east. Its history dates back to the early custom of founding Monastic settlements on small islands and it was manifest in the choice of St Adrian, when, in the ninth century, he and his brother monks established their retreat on the Isle of May. Later, in the twelfth century, King David I founded a monastery on the island which he granted to the Benedictine Abbey of Reading in Berkshire. This was on the condition that nine priests be placed there to celebrate divine service for the souls of the founder, his predecessors, and successors, the Kings of Scotland. The Benedictine monks continued in peaceful occupation until the fifteenth century when the monastery was possessed by the sea of St Andrew. This act saw the disbanding of the settlement, and with the ravages of marauding invaders and the passage of time the buildings gradually fell into disrepair. Today the only remaining evidence of the island's religious past is the fragmented remains of the chapel built in the twelfth century and dedicated to St Adrian. The island is perhaps best known among naturalists for its bird observatory which was launched in 1934 under the auspices of the then newly formed British Trust for Ornithology. It was on similar lines to the famous German Observatory at Heligoland and was the first in Scotland and only the second in the British Isles, the other being on Skokholm Island off South Wales. The studies of bird migration, varied seabird breeding populations, the island's own breed of mice and the island plant communities are all added attractions for visitors, in addition to the geology, the history and the lighthouses. The ledges of the West and South Cliffs carry a large breeding population of guillemots, shags, kittiwakes, razorbills and a few fulmars. Hundreds of puffins nest in burrows on the east and north of the island; the flatter areas of the island's surface are almost entirely occupied by herring and lesser black-backed gulls. The island was declared a National Nature Reserve in 1956. A lighthouse has been operating on the Isle of May since 1635 in which year King Charles 1st granted a patent to James Maxwell of Innerwick and John and Alexander Cunningham of Barnes to erect a beacon on that island and to collect dues from shipping for its maintenance. This light, however, was a crude affair and consisted of a stone structure, surmounted by an iron chauffeur in which there burned a coal fire to serve as the illuminant. The coals were hoisted to the fire by means of a box and pulley and three men were employed the whole year round attending to the fire which consumed about 400 tons of coal a year. In 1790 a lightkeepers' entire family was suffocated by fumes, except for an infant daughter, who was found alive 3 days later. Despite the fact that the light was regarded in its time as one of the finest in existence, its value as an aid to navigation, judged by today's standards, must have been decidedly limited. The character of the light would naturally vary considerably with almost every change in weather conditions; One minute it might be belching forth great volumes of smoke and the next blazing up in clear high flames, while changes in wind directions would tend to alter its appearance. An easterly wind for instance would have the effect of blowing the flames away from the sea so that the light could scarcely be seen where it was most wanted. An instance of this occurred on the night of 19 December 1810 when two of HM Ships NYMPHE and PALLAS were wrecked near Dunbar because the light of a lime kiln on the coast had been mistaken for the navigation light on the Isle of May. In 1814 the Commissioners purchased from the Duke and Duchess of Partland the Isle of May, together with the old coal lighthouse which was built in 1816. It was converted to a Rock Station on 9 August 1972 and looks a bit like a small castle with its protective battlements.