Bird and flower evolved together

This is the favorite flower for the Swordbill Hummingbird. Commonly referred to as Trumpet Flowers, the long tubular flower can only be pollinized by the long bill of the Swordbill Hummingbird. The flower produces large amounts of nectar which attracts the birds. These flowers and the hummingbird evolved together; the hummingbird will feed on other flowers and even feeders, but the flower can only be pollinized by the Swordbill.