The most important wintering areas are the Eastern Visayas, i.e. the islands of Leyte, Bohol and Cebu in the Philippines, and the Malaysian states of Sarawak and Selangor where between one third and a half of the world population are believed to winter, based on the results of a winter census undertaken in 2004/05. The total population is estimated at 2,600–3,400 individuals. During the decade from 2002 to 2012 there was no significant decline in the population of this species, and there are newly discovered colonies off the coast of southern China which may represent increased observer effort, but could also indicate a real growth in the population.