Questions often come up about nectar ratios for hummingbirds, orioles and butterflies. We recommend the following water-to-sugar nectar ratios: Hummingbirds 4:1, Orioles 6:1, Butterflies 18:1.
Our recommendations reflect the opinion of the majority of experts - nectar should always be made from common table sugar (sucrose) as it is the closest possible duplicate of natural flower nectar, and it should never contain any dye or other additives.
The WBU recommendation for hummingbird nectar is a 4:1 ratio; 4 parts water to 1 part sugar. The overwhelming recommendation in the industry for making hummingbird nectar is a solution of 4 parts water to 1 part white table sugar (sucrose). This concentration has proven safe and attractive to hummingbirds. It also mimics the natural concentration (20%) of the average natural nectar sources on which hummingbirds feed.
There is some concern that increasing the ratio beyond 3:1 may cause dehydration and kidney damage in hummingbirds due to the lower concentration of water in the solution. While we have been unable to find a definitive research document to confirm this, we believe being cautious is the best approach for now.
Another advantage to the 4:1 concentration is that hummingbirds will feed more frequently on a weaker solution than on a stronger one. Thus they may visit your feeder 10 to 12 times an hour in comparison to three or four times an hour with a richer solution.
Red Dyes, Additives & Preservatives
Equally important, red dyes should not be added to the sugar water. There is concern over the possible health effects of these dyes and other additives. Owing to the volume of nectar they ingest everyday, and their potential life span of 5-10 years, the long-term health effects of the dyes on the hummingbird's digestive system are not fully known.
We have done extensive research while reviewing numerous nectar products and we have found no additives and/or preservatives that we can confirm as being proven completely safe for hummingbirds.
Unfortunately, in dealing with the controversy over red dye in nectar, the research simply does not exist to identify, prove or disprove any of the potential health impacts that these additives may have on hummingbirds.
Until research and testing provides more reliable information, our recommendation for helping to attract hummingbirds to feeders without any red coloration is to place the feeders in areas planted with known hummingbird nectar plants and/or tie red colored ribbon onto the feeder to catch the attention of the hummingbirds in the area.
Nectar should always be made from common table sugar (sucrose) as it is the closest possible duplicate of natural flower nectar. We do not recommend sugar alternatives such as honey, artificial sweeteners, raw sugar, organic sugar, brown sugar or agave nectar. They contain ingredients that may be directly harmful or could build-up with regular feeding and become harmful to hummingbirds.
The WBU recommendation for oriole nectar is a 6:1 ratio; 6 parts water to 1 part sugar. There is no industry standard for oriole nectar. Cornell Lab of Ornithology is of the opinion to offer a 4:1 solution out of convenience based on the fact that they have not run across any research on the topic and orioles have been observed drinking from hummingbird feeders. They mention this ratio on their Project Feeder Watch web site. The 6:1 solution has historically proven to be effective in attracting orioles across the WBU system. After our own thorough research, there is no compelling evidence to change the WBU recommendation from the 6:1 ratio.
Furthermore, orioles are more effectively attracted to feeders when offered multiple food options. They are known to enjoy orange slices, grape jelly and mealworms offered from tray-style feeders. They will even use the protein-rich mealworms to feed their nestlings.
WBU has recommended in the past and continues to recommend a butterfly nectar ratio of 18:1. There is no industry standard for a butterfly nectar ratio. Most sources agree that the ratio should be between 10:1 and 20:1. Different butterfly species feed from different nectar sources with varying nectar ratios. The most effective way to attract butterflies is to provide the appropriate nectar plants and host plants for the desired species. Beyond an attractive habitat, customers can offer a pre-made nectar solution in a butterfly feeder as well as offering overripe fruit such as bananas, pears and other juicy fruits. We see no compelling evidence to change the recommendation from 18:1.