100 Red Dragons

There are 100 red dragons on an island, none of whom can see their own color but can see the colors of others. They are not social and never talk to each other. Importantly, they do not want to be red on this island. If a dragon ever discovers it is red, it leaves the island on the next daily boat (and they all know this). Every day, all the dragons come to see if any dragon is leaving. On day 1 there is a public announcement that at least one dragon is red. What will happen?