I started my fascination with Hummingbirds at the very young age of 4 years old. I remember my mother holding me up to the window above the kitchen sink and pointing to a tiny walnut sized Hummingbird nest carefully lodged in the small branches of a Pink Mimosa tree. I was fascinated by the tiny birds and could not get enough of them. Everywhere I went, I would listen and look for them, feed them and study them. Fast forward to today and I am still listening and looking for them, feeding them and studying them.
We are fortunate enough to live in Southern Arizona where there are about 16 -17 different kinds of Hummingbirds that live, winter and or migrate through our area. It is because of the variety of birds year round that we have been able to observe, evaluate and test various feeders, accessories and nectar solutions. That being said, we also do our share of reading books, articles and research papers as well as, consulting expert birding web sites like Cornell Lab of Ornithology and the National Audubon Society. I also have joined several social media birding sites to get a feel for what the public shares, knows and understands about Hummingbirds.
One of the most frequently asked questions I see is, “how do I make the nectar or sugar water for hummingbirds and what is the best recipe?” I always thought the correct answer was the straight forward 4 to 1 ratio of water to sugar. However, it turns out that the 4:1 or 20% sucrose ratio is not always the correct answer just like red is not always the preferred color for flowers. Read on to see what the experts have to say.
Various theories, based on field experiments, have two schools of thought when it comes to hummingbird choices for flower nectar. One theory is that hummingbirds feed randomly and the second theory is that hummingbirds seek out certain flowers of particular colors and shapes. The random theory proposes that hummingbirds visit all flowers of all colors and shapes and learn by chance which flowers produce the most and sweetest nectar. This means that the birds occasionally get lucky with a sweet flower but aren’t particular or have a preference for flower shape or color. The seeking theory proposes that hummingbirds purposely visit certain types of flower with particular shapes and colors because they contain higher concentrations of sucrose than other flowers. In fact, in South America, hummingbird species and flowers have adapted or evolved to each other: the flower being long and tubular shaped and the hummingbird’s beak matching the curvature and length of the tubular flower. The Little Hermit Hummingbird of Venezuela below is a perfect example.
Below are several links to Academic studies done on the production of nectar and preferences for Hummingbirds, Insects and Bats. The papers are very informative and contain statistical data as well as references to previous studies..If you want the short versions, I would suggest reading the Abstracts. Basically, Hummingbirds will consume nectar at higher concentrations of sucrose at feeders at a ratio of 3:1 or 25% sucrose and higher. https://sora.unm.edu/sites/default/files/journals/auk/v112n02/p0456-p0463.pdf However, the limiting factor for Hummingbirds and nectar appears to be the increased viscosity of higher concentrations of sucrose in nectar: the higher the concentration of sucrose, the thicker the nectar and the longer it takes for the bird to take up the nectar. Lower temperatures also increase viscosity, thus, more time feeding may increase the chances for predation. However, as noted in the NCBI article dated 2006, (see second link below), the study concluded, “The driving force to visitation appears to be the volume of nectar the visitor can expect to consume.”
Baker, Herbert G. “Sugar Concentrations in Nectars from Hummingbird Flowers.” Biotropica, vol. 7, no. 1, 1975, pp. 37–41. JSTOR, www.jstor.org/stable/2989798.
Here is an interesting citation which concludes that plants adapt to the behavior of their pollinators.
Abrahamczyk S, Kessler M, Hanley D, et al. Pollinator adaptation and the evolution of floral nectar sugar composition. J Evol Biol. 2017;30(1):112-127. doi:10.1111/jeb.12991
So, do Hummingbirds have preferences for flowers and color? Based on the research, the answer is maybe. The articles above suggest that certain flower shapes contain higher concentrations of sucrose and maybe more nectar because the rate of evaporation is less than that of an open faced flower. And, if plants evolve to more successfully accommodate certain pollinators, then tubular flowers with more and sweeter nectar, plus colors in the right light spectrum make very good sense for attracting Hummingbirds. This may explain the many specialized Hummingbirds and flowering plants dependent on each other in South America.
But what do all these academic studies mean for the backyard Birder? First and foremost is the education and the facts to be a successful caretaker of Hummingbirds and to distinguish fact from myth. Here is a breakdown of the basic facts from the articles:
Nectar from flowers visited by Hummingbirds is composed mainly of water and sucrose. Sucrose is a compound sugar of glucose and fructose. Sucrose for the purpose of making feeder nectar is found in white Beet or Cane Sugar. There is no evidence that mixing additional sugars or adding minerals or vitamins to the nectar is beneficial to the Hummingbirds. Dyes, juices, sodas, brown sugars, turbinado sugars, other sweeteners (artificial or natural) are never to be fed to Hummingbirds.
Nectar solutions can vary from 4:1 or 20% to 3:1 or 25%, even as high as 35%. There is no scientific data to suggest that higher sucrose levels are harmful to the birds since nectar with higher sucrose concentrations do exist in wild flowers. Most wild flowers in the US have nectar that is below or at a 25% sucrose level, thus 4:1 or 20% is very acceptable for feeder nectar but so is 3:1 or 25%. There is also no evidence to suggest that nectar needs to be a particular temperature for the birds to feed. We have witnessed Hummingbirds poke holes through frozen crust in the nectar bottles during a cold spell, consequently, nectar temperature does not appear to be a factor for feeding from feeders.
Hummingbirds will feed from all flowers but have a preference for tubular shaped flowers which appear to contain more and sweeter nectar.
There does not appear to be a color preference among Hummingbirds for feeders or flowers. Hummingbirds have vision in the red, green, blue and ultraviolet light spectrums, consequently, they see more color than humans and the color red is not necessarily preferred over other colors.
Hummingbirds do not appear to prefer wildflowers over nectar feeders. In fact, several of the articles report that nectar feeders actually make feeding easier for Hummingbirds because of the availability of a “pool” of nectar.
Hummingbirds feed via their long tongue which utilizes a complex capillary action and not sucking like bees or viscous dipping as bats. Cleanliness is of the utmost importance in keeping the birds healthy. Be sure to clean feeders often, especially, daily in temperatures above 90 degrees since bacteria is introduced by the birds every time they feed. Also, mold and fungus rapidly build up in the heat and will sicken the birds.
Hopefully, the information in this Blog has been useful and educational. As always, we welcome feedback in the form of questions or comments. If you have other topics with regards to Hummingbirds that you would like to see discussed, please feel free to contact us and we'll see about researching and covering those ideas in our Blog.
Until next time, take care, stay safe and Happy Birding!
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