Hummingbird Color Preferences
By Jon Friedman
The colors hummingbirds are attracted to have been an area of interest to researchers for many decades. Some of the earliest documented scientific research and experiments have been dated to the early 1920’s. Prior to the advancement of hummingbird feeders, researchers conducted their experiments almost entirely with natural nectar producing flowers – which have an extremely wide range of colors. It should be noted, even though color associations have been acknowledged as important to hummingbirds and their flowers for over one hundred years, not enough research has been accomplished to date to make definite pronouncements in regard to color preferences. In this regard, the more we learn, the more questions arise and, again, demonstrate the need for further research.
Each continent around the world has nectar producing flowers. Most regions, anywhere in the world, may have a predominance of any single flower color, in association with a wide array of other secondary colors. In the western United States, red seems to be the most abundant color among the nectar producing flowers. This is also true in the equatorial tropics as well. However, the flowers of the species of Marcgravia, native to Brazil are immensely popular with the native birds of that region and they are a dull brownish color. In Mexico, certain regions have predominance’s of the purple Penstemon campanulata and the dark blue Salvia Mexicana. When these flowers are in bloom, the local hummingbirds prefer their nectar. Many conflicting studies have been conducted and the general consensus, looking back over time, is that experimental investigation of the color sensitivity of hummingbirds leaves much to be desired.
Most of the research work in determining color preferences of hummingbirds has been done in the United States and Mexico. And, the results refute the older, commonly accepted notion that these birds always prefer red to all other colors.
There are many factors which may be involved in determining color preferences. The sweetness level of nectar producing plants varies widely by species. The time of year the plants mature may be a factor. The elevation of those plants could provide another explanation for certain preferences. The geographic distribution of particular species of flowers plays a role. The position of the flowers on a given plant yields different results and some flowers change colors with the seasons. Researchers noted that in certain cases, a particular perch seemed to be more important than the color of the flower – indicating that location may trump color.
Some researchers thought that the time of day may play a factor in determining which flowers were visited. In broad daylight some experiments showed hummers accepted nectar from almost any color of flower. At dawn and dusk, the same hummers exhibited the same behavior as they displayed at mid-day, feeding on flowers of many colors. The results of the study were inconclusive due to the fact that time of day or amount of sunlight played little part in deciding preferences.
Longer, better funded studies are needed to determine color feeding preferences for hummingbirds. Critical tests are difficult to design, and past experience and conditioning of individual birds is hard to assess. Tests done with wild hummingbirds often derived different results than the same tests done with captive hummingbirds. By 1950, a group of researchers (Lyerly, Riess, and Ross) pointed out that the assumption that hummingbirds in the American west preferred red flowers seemed to be based on the fact that red flowers predominated in the region, and that experimental evidence contradicts that and fails to show such a preference.
An interesting statistic derived from examining the results of many color tests were that yellow seemed to be the least preferred flower color for hummingbirds. Bees, it was noted, seemed to prefer the yellow flowers more than hummingbirds. Most experiments, with wild and captive hummingbirds, suggest that they visited colors other than yellow almost equally. Red flowers were later learned to have the richest concentrations of nectar. It is thought that most North American hummingbirds are migrants, traveling great distances each year and that the association of the color red and nectar eliminated the costly trial and error process of seeking out potential new sources of nectar. During migration, these birds use most of their energy to travel great distances and therefore don’t have excess energy to seek out unfamiliar nectar sources. Hummingbirds, as do all pollinators, remember all the nectar sources they have visited in the past. This long-range memory certainly must be valuable to hummers in migration as it guides them to familiar fueling stations all along their way. Better to use something that’s proven. Better safe than sorry.
Other theories that seems to have some influence on why, especially in North America, red flowers may predominate as the most used flower color include: the fact that many red flowers have the sweetest concentration of nectar (between 13% and 28%); hummingbird vision in the warm ultra-violet spectrum of light is superior to that of the cool ultra-violet spectrum of color; and many yellow nectar-producing flowers that were originally bee pollinated eons ago have evolved into red with the emergence of numerous hummingbird pollinators.
Color of Hummingbird Feeders
Now, the question of color comes into play when considering the colors that manufacturers of hummingbird feeders use. Nearly everyone, if asked, would agree that red is the most used color in commercial feeders. Why is that? The answer is that the overwhelming majority of feeders manufactured in the United States (and overseas – as in China) are red because the industry “dictates” the use of that color. Only a miniscule percentage of the manufacturers actually have a research and development department or design artists/engineers to assist in realizing new breakthroughs in this technology. Most simply note that competitors are using the color red and assume that this is the “correct” color to use. When pressed, most will answer that red is the color of flowers that they see hummingbirds most frequently use. Very little research or knowledge accompanies this simple answer.
Throughout much of the 1990’s, the Wild Bird Store worked in close association with Aspects, Inc. of East Warren, Rhode Island. In my opinion, Aspects led the industry by creating the best designs for the wide variety of feeders they made for many years. In addition to their higher standards of design quality, Aspects designed for ease of use (both for hummers and the humans who maintain/clean them), offered construction utilizing superior materials, weather-proofing, and the unconditional lifetime guarantee offered on every product is simply the best.
As consultants and field-testers, we critically examined and observed how well their feeders work. Unlike many other companies, Aspects looked for ways to further improve their products. Most other companies are satisfied with copying competitors’ designs (usually with a ten percent design change to avoid infringing upon existing patents). Aspects did their own designing and in-house testing but knew the company benefited with outside, objective testing. The company actually invited feedback from all sources, including the end users – the customers who actually feed birds.
During the 1990’s, we played an active role in this process. For over a year, we discussed what role color plays in attracting hummingbirds to feeders. Most manufacturers simply assume red to be the best color in attracting hummingbirds, consequently red hummingbird feeders dominate the market. We wondered if other colors would prove to be as successful. So, we were determined to find out. After several months of field-testing, we were somewhat surprised by the results.
Nectar producing flowers that exhibit color in the warm ultra-violet spectrum (yellow, pink, peach, orange, the reds and purple) yield nectar that has a sweetness level of 19 to 21 percent (hence the five to one ratio recipe). Flowers in the cool ultra-violet spectrum (white, the blues and violet) average considerably less sweetness in general (5 to 18 percent). The warm colored flowers are more numerous than the cool colored flowers in nature, so it is no surprise that hummingbirds prefer these flowers. While Aspects always the regarded the practical and functional use of the feeders from the bird’s perspective as a high priority, how the human customer views their products is also a business concern. After all, this plays a major role in the marketing of these products. Understanding all this, we discussed experimenting with a wide range of colors to determine how significant color alone is at attracting hummingbirds.
We decided to experiment using a single model, the Mini Hummzinger. This is a small 8 ounce pan-type feeder with a clear polycarbonate, UV stabilized body. We began the experiments by using six feeders, each with a different colored lid. The lids of the mini’s have three food ports each. In the first part of the experiments we placed the feeders in the same exact locations that the birds were used to but changed the standard lid colors. Two were different hues of red than the normal red Aspects used in their production models. The others were forest green, royal blue, yellow ochre and steel gray. To our surprise, the birds didn’t hesitate coming to any of these feeders. We knew they registered the exact location of each of their feeding sources in their brains, so we realized that the colors might not have thrown them off for that reason. Next we took those same feeders and relocated them to new areas where there hadn’t been any feeders before that. Again, we were surprised that the hummers didn’t hesitate to use any of the feeders in their new locations.
We discussed the results at great length with the Aspects chief designer and his staff. We decided to try a new twist on the existing idea. He sent us a new set of lids, again painted in non-traditional colors. But this second set of lids had three different colored food ports on each of the lids. We added various metallic and earth colors to the array of colors we were using. In both the familiar locations and in new locations, the hummingbirds were very quick to adapt to the new colored feeders. In discussing these findings with the Aspects team, we suggested that the colors used seemed to make no difference whatsoever. We mentioned that migrant hummers, who had not been to these locations and were unfamiliar with these feeders, used them as quickly as the resident hummers who knew the feeders and the locations well.
We surmised that the shape and form of the feeders might possibly hold a clue here. After all, we were using the same model but only altering the colors. Being a non-scientific experiment, we used only the 8 ounce mini model to achieve some semblance of scientific approach. Our non-scientific brains thought that if the size, shape, capacity of the feeders were the same – the colors would be the most obvious variable. Thus, the results would reflect a truer sense of the effect of the color of the feeder.
So, we were all a little surprised to discover that, as far as our field testing was concerned, the hummingbirds came to all the various color permutations of the feeders as well as they do the normal red that most manufacturers use. This information, along with that of other field-testers, lead us to think that Aspects could lead the market with a variety of non-traditional multi-colored hummingbird feeders. They did produce a limited number of variously colored feeders (hot pink, purple, mauve, raspberry and turquoise) but the buying public was not quick to embrace such unconventional colors – even if the hummers had no objections. So, I tell customers that the color of the feeder is of little importance. What is more important is the overall design and what is most important is what you put into it!