Stir until all sugar is dissolved and the syrup is clear. This is about the same ratio of sugar to water as found in the nectar of many flowers. Store leftover syrup in the refrigerator. Do not use honey or artificial sweeteners in place of sugar. Honey ferments quickly and can cause a fungus that damages the birds' tongues.
Artificial sweeteners have no food value.
Red food coloring should not be added to the syrup. There are still questions about its safety for human or animal consumption. The dye is thought to cause liver tumors. It is also expensive and since feeders already have red decorations to attract the birds, colored syrup is not necessary. Hummingbirds do not have hollow tongues, nor do they use their long bills to suck up nectar.