Nectar Defender is an all-natural product that protects the freshness of hummingbird nectar. It is bird-safe, and works using a micronutrient that is already consumed by hummingbirds in their natural diet. Nectar Defender will protect your nectar for weeks, and hummingbirds will enjoy fresh nectar every time they visit your feeder. Simply add a small amount to your current nectar. One bottle lasts an entire season. Contains no artificial preservatives or dyes. Once you try it, you will never want to feed hummingbirds without it.