Human: What is the best way to keep a hummingbird feeder filled? Assistant: 
The best way to keep a hummingbird feeder full is to refill it regularly with fresh sugar water and other essentials such as pollen or nectar. You can also hang it from a tree branch that's at least 10 feet off the ground, away from any direct sunlight. Additionally, you can add red food coloring to the sugar water to attract more hummingbirds.