The posts lately have been hummingbird heavy, but you can blame the time of year. Both southbound migrants and a few remaining locals—Rufous, Broad-tailed, Black-chinned, Anna’s, Broad-billed, an occasional Calliope, Costa’s, or Violet-crowned, and our yard’s first Lucifer—have been shrieking and jousting outside my living room window every daylight hour, so it’s hard to think about anything else (which makes it hard to get any real work done but also keeps my mind off things I’d rather not dwell on).
This is going to be a heavy post, so I’m dividing it into three parts. If all you’re interested in is what you should/shouldn’t put in your hummingbird feeder, you needn’t read any further than the end of this installment. If you’re curious about how these recommendations came about—the science and history behind them—I hope you’ll come back or click through to read the second and third installments.
Let’s kick things off with something happy. Happy, happy, happy. No stress, no angst.
Okay, down to business. At the request of my friend and colleague Laura Erickson, who writes and edits for the Cornell Laboratory of Ornithology, I’m finally tackling this long-neglected and often controversial topic. Here is what you need to fill your hummingbird feeder:
1. White sugar.
- Sucrose (a.k.a. white table sugar) is the main sugar in the sap of plants and also in the nectar of hummingbird-pollinated flowers (1). We squeeze sugar cane and sugar beets to get our sucrose, and hummingbirds drink nectar, sap, and properly made feeder solutions to get theirs. It does not give them diabetes. It will not rot their teeth.
- If ordinary granulated sugar doesn’t dissolve fast enough for you, and you don’t mind trading cost for convenience, buy superfine baker’s or caster sugar instead (but not powdered sugar, which contains anti-caking agents).
- Though pure cane sugar is often recommended over pure beet or blended sugar (which is usually labeled simply as “sugar”) based on the perception that it tastes better to the birds, it takes sophisticated testing for food scientists to distinguish between them. Sugar cane yields somewhat more sugar per acre than sugar beets but uses much more water, displaces more biodiversity, and has to be transported farther (at least in U.S. markets), so beet sugar may be the “greener” choice.
2. Good-quality water.
- If there’s any reason that you don’t personally drink your tap water (too many minerals, has a funky taste or smell, tested positive for pollutants, etc.), don’t make your hummingbird guests drink it, either. If it’s discolored by iron, you definitely shouldn’t use it to make feeder solution (see the second bullet point under the “don’ts” below).
- Researchers have determined that hummingbirds’ kidneys are incredibly good at getting rid of water without losing their bodies’ electrolyte salts (2), which clears the way for feeder solutions made with water purified by reverse osmosis or distillation. Water softened by ion exchange is high in sodium, and overloading the birds on sodium may not be a good idea.
Sugar. Water. That’s all you need. Really.
The list of things you should not put in your hummingbird feeder is a wee bit longer:
- Honey. It’s a natural food, but only if you’re a honeybee. Bees start with the nectar of flowers not typically used by hummingbirds, modify it with digestive enzymes, then barf it back out and evaporate off most of the water. The final product contains less palatable sugars plus stuff you seriously don’t want to feed to hummingbirds. Once diluted to feeder strength, honey becomes an ideal food for a variety of microbes, including some that can cause disease. Honey-water diets have been linked with fatal yeast infections (candidiasis) in captive hummingbirds (3), and similar infections have been reported in wild ones. Honey belongs on your biscuits, not in your feeders.
- Brown or even brownish sugar. The color derives in part from iron, for which nectarivorous and frugivorous birds have a very low tolerance (4,5). Even a little extra iron over time can build up to lethal levels in the birds’ bodies. Refined white sugar has had the trace iron removed to make it a more attractive product, which incidentally makes it safer for hummingbirds. Unfortunately for those of us who try to shop green, organic sugar is typically not fully refined to pure sucrose, so it’s not safe. Rumors of problems at tropical feeding stations may be related to the use of lightly refined turbinado (“raw”) sugar containing iron, but these reports have yet to be substantiated.
- Artificial coloring. The vast majority of hummingbird flowers put the color on the outside, not in the nectar. FD&C Red #40 and #3, the dyes used in most “instant nectar” products and the food coloring in your pantry, are like nothing the birds would ever encounter in nature. They may not be dangerous at human consumption levels, but hummingbirds can drink more than 5 times their weight in liquid in a day. Medical research has linked large dosages of these dyes to a number of serious health problems. Backyard comparisons also suggest that the birds don’t like the way these dyes taste. If colorless sugar water just doesn’t look right to you, use a few drops of fruit juice concentrate to tint it.
- Artificial and non-nutritive sweeteners. This includes saccharin (Sweet’N Low®), aspartame (Equal®, NutraSweet®), sucralose (Splenda®), stevia (Truvia®, PureVia®), monkfruit or lo han (Nectresse®), acesulfame potassium (acesulfame-K), erythritol, and xylitol. Hummingbirds need the calories. If they get fat, it’s for a good reason, and they won’t stay that way for long (unlike us big sluggish primates.)
- Commercial “instant nectar” and “hummingbird food” products. Most contain unnatural additives such as dyes, preservatives, and/or flavors that, despite what manufacturers and retailers may claim or imply, have never been tested or approved as safe for hummingbirds. Those products without additives are basically overpriced boxes of extrafine white sugar (see the second bullet point under “White Sugar” above).
- Nutritional supplements. The nectar of hummingbird flowers is little more than sugar water anyway (1), and anything else you add can cause premature spoilage and other problems. This includes commercial diets for captive hummingbirds, protein powder, fruit juice (except a few drops of concentrate to add a little color), Jell-O, Gatorade, Mountain Dew, vanilla extract, and strawberry daiquiri mix. Hummingbirds are really efficient hunters, even in winter, but if you want to supplement their protein/vitamin intake, raise fruit flies in jars or start a compost pile. For minerals during nesting season, offer clean ashes from natural wood (no synthetic logs, paper, trash, etc.).
Now that we have the two ingredients, the next step is determining what proportion to mix them in. Though opinions about feeder solutions vary slightly within the hummingbird community, most hummingbird experts still endorse this recipe:
4 parts water
1 part sugar
Good old 4:1 has proven itself safe and effective over more than four decades of use, it’s well within the range of sugar concentrations found in the nectar of hummingbird pollinated flowers (1), and, like a one-size-fits-most garment, it leaves enough “wiggle room” to accommodate some challenging environmental conditions without short-changing the birds on either energy or water. Hardcore hummingbird fanatics may have sound reasons for using slightly stronger or weaker solutions, but all the average hummingbird host needs to remember is 4 parts clean water + 1 part white sugar.
Stay tuned for part II, the science behind hummingbird feeder solutions.
1. Nicolson, S. W. and P. A. Fleming. 2003. Nectar as food for birds: the physiological consequences of drinking dilute sugar solutions. Plant Systematics and Evolution 238(1-4):139-153.
2. Lotz, Chris N. and Carlos Martínez del Rio. 2004. The ability of rufous hummingbirds Selasphorus rufus to dilute and concentrate urine. Journal of Avian Biology 35(1):54–62.
3. Orr, K.A. and M. E. Fowler. 2001. 18: Order Trochiliformes (Hummingbirds). In Biology, Medicine, and Surgery of South American Wild Animals, Murray E. Fowler, Zalmir S. Cubas Eds. Iowa State University Press, Ames, Iowa.
4. Frederick, H., Dierenfeld, E., Irlbeck, N., and S. Dial. 2003. Analysis of nectar replacement products and a case of iron toxicosis in hummingbirds. In Ward, A., Brooks, M., Maslanka, M., Eds. Proceedings of the Fifth Conference on Zoo and Wildlife Nutrition, AZA Nutrition Advisory Group, Minneapolis, MN.
5. Ketz-Riley, C.J. and C. Sanchez. 2015. Chapter 26: Trochiliformes (Hummingbirds). Pp. 209-213 in Fowler’s Zoo and Wild Animal Medicine, Volume 8, R.E. Miller, M.E. Fowler eds. Elsevier (Saunders).