We couldn't understand why we were not geting any papaya. The trees were flowering, but as soon as the little fruit started to show it would drop on the ground. Lots of flowers, no fruit.
Then one day we noticed a "Bobo" picking the flowers from the tree. The Red-vented Bulbul feed mostly on fruit and flowers. Another introduced, invasive species, these little birds are a real pest for farmers and gardeners.
At a Boy Scout Merit Badge class for Gardening, I noticed a bush with several CDs tied to it. I ask what was with the CDs and was told they are a great way to keep the birds from eating the young fruits. He said lots of farmers hang CDs from wires cris-crossing their fields. Something about the sun flashing off the CD keeps the birds away.
Sooooooooo, I tied two CDs on my papaya tree and within a week... lots more flowers..... little fruits appeared and started growing.