A few days after all four of the butterflies were born out of their cocoons we took them outside in the backyard to see if they would fly away. Ruby opened their habitat and showed them how to flutter their wings. She sang a "time to come out" song and watched as three of them fluttered up and away. (I will try to upload a video of this.)
Lucy, the fourth one, was the last to be born by several days so she may not have been ready to fly yet. She just did not want to get off her banana slice no matter how much we encouraged her.
We took Lucy back inside and gave her a few more comfortable days in Ruby's room to snack on sugar water, orange and banana slices and to dry her wings. She stayed on her banana and ate it by unrolling her long proboscis tongue, which works like a straw. Lucy the butterfly became very special to Ruby since she stayed so long in Ruby's room.
Every day we took Lucy out and unzipped her cage.
Finally, on a nice sunny day, she got very excited. She flopped around as soon as we took the cage into the sun. Then she flew away to join the rest of her friends.
The next day Ruby saw some white butterflies at daycare and asked them if they knew her butterflies. Ruby also showed pictures of the whole caterpillar-to-butterfly process to her friends at daycare. Everyone was impressed!
We were very lucky with this process. Another mother told me that when she released her butterflies, a bird flew by and ate them.