What would Hainan be like if migratory birds didn't come to Hainan?

Whether there are migratory birds or not should have little impact on Hainan. The pillar industry of Hainan Province, especially Sanya, is tourism, and the tourism resources are mainly to receive tourists. Old people who live there will not go to beaches, scenic spots, hotels and restaurants. Renting a house for winter should be the same as buying food and cooking in the north, otherwise those houses will be vacant and will not add extra burden to Hainan residential areas. I'm from the northeast, but I don't understand why I want to go to Hainan for the winter. In the north, there is heating indoors and cars when going out. Who will be silly and frozen out? On the other hand, Hainan's humid air, strong ultraviolet rays, high prices, typhoons and heavy rains do not make people feel very comfortable.