most likely eradicated on the island. Rabbits are currently the only grazing animal and in the 1960s myxomatosis decimated the population and led to an increase of scrub on parts of the island, especially "the neck" where in some years cuckoos (Cuculus canorus) were attracted by the large numbers of garden tiger moth (Arctia caja) and other large caterpillars. In one year the number of garden tiger larvae was 90 per square metre. The last grazing animals left in 1974 and Natural England would like grazing animals back on Gugh to counteract the effects of the scrub and dense sward of grass covering parts of the island. A cobalt deficiency in the soil means grazing animals need supplements. In the southern part of the island large colonies of lesser black-blacked (Larus fuscus graellsii) and herring gull (Larus argentatus) breed, as do a small number of greater black-backed gull (Larus marinus). Storm petrel (Hydrobates pelagicus) and kittiwake (Rissa tridactyla) no longer breed there. To protect and enhance the islands' seabirds, and to protect Annet (an important breeding site) from re-invasion, a feasibility study was carried out to see if it was possible to eradicate rats from the Isles of Scilly. A winter trapping survey on St Agnes and Gugh indicated that those islands had a population of 3,300 brown rats. It was found the rats foraged on a variety of food including Scilly shrew which were found in the stomach contents of 18% of the rats trapped. Furthermore, numbers of the shrew were higher in areas where the rats were controlled; an indication that rats are having an effect on their numbers. 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. 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. Following the rat eradication programme 12 Manx shearwater chicks fledged on Gugh and St Agnes in September 2014. Vagrant birds A white-tailed eagle (Haliaetus albicilla) with a wingspan of 7 ft 6 in (2.29 m) was shot on Gugh in November 1909. A white-tailed eagle (Haliaetus albicilla) was seen on the Isles of Scilly (and Bosigran, Zennor) from April 1947 onwards. It was thought to roost on Gugh