The Isles of Scilly he isles of Scilly form an archipelago（群岛）off the southwestern tip of Cornwall. They are comprised of 140 islands and islets. Scientific evidence suggests that the Isles were likely much larger in ancient times and that many of them would have been joined into one island.Rising sea levels over time have led to the current geography. Up until the early twentieth century, the residents of the Isles of Scilly practiced subsistence living（自给生活）, raising their own livestock and crops and catching fish to eat. Today, things are quite different. The Isles are well known for their flowers, particularly daffodils, which are their chief agricultural product. Otherwise, the Isles today depend largely on food other products ted from the mainland, though fishing remains a popular pastime, if not a significant source of income. The main industry on the Isles today is tourism, making up 85% of the islands’ total income. The favorable summer climate, conducive to flowers and holidays, facilitates the large amount tourism in the area.The bulk of tourists visit St. Mary’s the only island with a significant road network and airport, though the island of Tresco also has a number of timeshare resorts and a heliport. The holiday season on the Isles of Scilly, unlike many other tourist destinations in England, extends through October, when the Isles are a top destination for birdwatchers who come to see the many exotic birds that make the first stop of their migration on the Isles. The dominance of the tourism industry on the Islands has caused some political problems. Sixty-three percent of the islands’ jobs come from the tourism industry, but the vast majority of these offer only seasonal or part-time work. Thus, the Isles employ a number of guest workers. Currently the average income on the islands is only 70% of the national average in the UK, whereas housing prices are, on average, £5000 more expensive than in the rest of the country. These factors make life difficult for those who make the Isles their home, though they continue to be very popular among tourists.