Instructions
Go to Costolots and purchase at least five turnip seeds. The more you buy, the faster and more reliably you'll be able to get a Hootyfruity.
Plant the turnip seeds in your garden. When they sprout, water them until smiley faces float over them. In time, they'll grow into mature turnips.
Observe your garden. Eventually, a Mousemallow will move in, attracted to the turnips. When it moves in, it will eat a turnip. In time, it will eat more turnips to stay alive.
Continue planting turnips until you have at least five Mousemallows in your garden. The Hootyfruity is attracted to Mousemallows. Once it eats five Mousemallows, it will move in, roosting in a tree.