Seven types of bees facing extinction in Hawaii have been placed on the endangered species list for the first time in the US. The listing of yellow-faced or masked bees on the federal register came after US wildlife authorities found that their numbers have plunged in recent years. The bees were once commonly found on the islands of Hawaii and its neighbour Maui but they have become endangered due to habitat loss, wildfires and the invasion of non-native plants and insects.