They do not like to talk about bird flu in Thailand's troubled deep south. The highly sensitive swifts that are the source of bird's nest soup's lucrative ingredient are colonising urban areas. It is a rare economic success story for the region where Muslim separatist violence threatens the future of traditional businesses. Rubber growers and fish canners are looking elsewhere, and tourists are avoiding the three southern provinces where bombs and shootings have killed more than 1,300 people since January 2004. But the birds keep on coming. The finger-sized swifts have started nesting in the thousands in abandoned shop-house lofts, hotels and warehouses. Purpose-built five-storey nesting 'boxes' now dot the coast as entrepreneurs seek to recreate the conditions of isolated caves traditionally favoured by the once-endangered birds. Pickers delicately harvest abandoned nests once a month, selling them to Bangkok exporters for up to US$1,000 a kilogram. 'The development of the nesting industry has been a remarkable thing to watch,' says prominent local businessman and recently elected national senator Anusart Suwanmongkol. 'It has given ordinary businesspeople something to smile about in some pretty grim times.' Mr Anusart's hotel was one of the first urban sites colonised by the birds about seven years ago. At eight storeys, it is the tallest building in Pattani. Apparently mistaking it for a seaside cliff, the birds swoop down its sides and settle in an unused basement. The birds are easily scared. Hotel staff keep noise down and are cautious in their use of charcoal, mosquito coils and other chemicals that may spook the birds. Mr Anusart said the swifts had provided a lucrative sideline for his hotel, which has seen occupancy rates slide to about 30 per cent over the past two years. Traditionally the area has attracted Singaporean and Malaysian tourists to its mosques and Chinese temples. That trade had dried up, Mr Anusart said. The three southern provinces - Pattani, Narathiwat and Yala - are among Thailand's poorest, with incomes 60 per cent of the national average. Unemployment runs far higher than the national average of 12 per cent, with more than 30 per cent jobless in some districts. Bordered on two sides by Malaysia, the area offers few of the beach resorts that attract the international tourists further north, in Phuket and Koh Samui. Rubber plantations have long been the key staple but reports this week suggest violence against rubber tappers is taking a toll. Officials at the Thai Rubber Tappers' Co-operative said investors were now eyeing plots in northern Thailand as the violence disrupts the local labour market. Rubber tappers work in the pre-dawn darkness in often isolated areas, making them easy targets. Major growers such as Thai Hua Rubber and Southland Rubber recently purchased large tracts of land and are planning to move, helped by better logistics further north. Rubber prices have been soaring over the past two years but analysts have warned of a glut as Thailand, Vietnam and Malaysia rush to expand production. Pattani is also home to an extensive Japanese-funded fish-canning business serving boats in the Gulf of Thailand. Industry sources said several firms were considering a move further north because of the violence. One factory producing kosher products for the Jewish market has already moved. The reports of relocations follow more than 70 bombings and shootings last week as insurgents escalated their campaign, striking playgrounds, government offices, military bases and railway stations.