When do you see the blue bird on Tree of tranquility?

to see the blue bird, you must get the person you like to 8 hearts and the mayor to 3-4 hearts. a few says after, Hamilton will come to your house and tell you about the Blue Bird of Happiness and how it's feather is a traditional marriage proposal. anywhere between the next day and 2 weeks later, when you leave your house, you will see a blue bird. Then

just follow the bird to Caramel Falls. They go around the path, past the waterfall; just as if you were about to go to the hot springs. Just keep walking and the scene will trigger when you are on the other side.