Feeding Hummingbirds: The Basics

A young Calliope Hummingbird on its first southbound migration refuels on plain sugar water.

With hummingbirds returning to their northern homes from their wintering grounds, it’s the perfect time for a short refresher course in the best (and worst) practices for feeding them. I’m assuming here that you already have a feeder you’re happy with, one that is easy to clean and refill and doesn’t attract bees. To fill it with a safe and effective substitute for flower nectar, you’ll need the following ingredients:

1. White sugar.

  • Sucrose, a.k.a. white table sugar, is a natural sugar that is the most abundant sugar in both the sap of plants and the nectars of hummingbird-pollinated flowers (1). We get our sucrose by squeezing sugar cane and sugar beets, and hummingbirds get theirs by drinking nectar, sap, and properly made feeder solutions. It does not give them diabetes. It will not rot their teeth.
  • Pure cane sugar is often recommended based on reports that the birds prefer it over pure beet or blended sugar (which is usually labeled simply as “sugar”). As yet there’s no hard evidence to support this.
  • If ordinary granulated sugar doesn’t dissolve quickly 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).

2. Good-quality water.

  • If you don’t personally drink water straight out of your home tap for any reason (too many minerals, funky taste or smell, tested positive for pollutants, etc.), don’t make your hummingbird guests drink it, either. If it’s cloudy or 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 excess water with minimal loss of 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 Basic Recipe: 1 part sugar + 4 parts water

Sugar water recipe

Filling your feeders with one part white granulated sugar dissolved in three to six parts good-quality water is a safe, effective way to attract hummingbirds. Leftover sugar water will keep in the fridge for up to two weeks.

Though opinions about ratios of sugar to water vary slightly within the hummingbird community, most hummingbird experts endorse this recipe. Good old 1:4 (or 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. Slightly stronger solutions (1:3) are helpful for migrating and wintering hummingbirds, and slightly weaker (up to 1:6) keeps them hydrated and cool in extreme summer heat, but all the average hummingbird host needs to remember is 1 part white sugar + 4 parts clean water.

Briefly boiling the solution on the stove top or in the microwave dissolves the sugar quickly and may delay spoilage by killing spores of yeasts, molds, bacteria, etc. in the sugar and/or water, but it isn’t strictly necessary. Sugar water spoils quickly no matter what you do, so clean and refill your feeders every three days in cool, mild weather and daily in very hot, windy, and/or rainy weather. My favorite cleaning method is to spray hydrogen peroxide on all feeder surfaces, let it soak for a couple of minutes, then brush and rinse to remove organic debris.


“Alternative” ingredients that don’t belong in hummingbird feeder solutions:

  • Fruit juice concentrates available from health food stores and online retailers are a safer alternative to artificial dyes.

    Fruit juice concentrates available from health food stores and online retailers are a safer alternative to artificial dyes. Here homemade sugar water has been colored with a teaspoon of tart cherry concentrate.

    Artificial coloring. The petroleum-based dyes used in commercial food coloring and most “instant nectar” products are like nothing the birds would ever encounter in nature. These dyes may not be dangerous at human consumption levels, but hummingbirds can drink two to five 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, tint it with a teaspoon of natural tart cherry or raspberry juice concentrate (available online and from health food stores) and clean your feeders more often.

  • Brown, beige, or off-white sugar. The color derives in part from iron, for which nectar-feeding 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, lightly refined organic sugar contains several times as much iron as conventional white sugar, so it’s probably not safe for hummingbirds.
  • Honey. It’s a natural food, but only if you’re a honeybee. 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 hummingbird feeders.
  • Commercial “instant nectar” and “hummingbird food” products. Most contain unnatural and unnecessary 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 grossly overpriced boxes or bags of sugar.
  • 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. These sweeteners do not provide the calories (energy) that hummingbirds need to survive.
  • 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, liquid vitamins, fruit juice (except a teaspoon or two of natural juice concentrate for color), vanilla or orange extract, Jell-O, and Gatorade. Hummingbirds are resourceful and efficient hunters, even in winter, but you can provide a safe protein/vitamin boost by raising fruit flies in jars or starting a compost pile. For minerals to help nesting females build strong eggshells, offer clean ashes from natural wood (no synthetic logs, paper, trash, etc.).

See this post for a more comprehensive list of “don’ts.”

Resources for this post:

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).

 

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One hummingbird species, two maps

Hummingbirds.net Ruby-throated map Mar 2012

The migration map from hummingbirds.net through March 2012.

eBird Ruby-throated map Mar 2012

The same time period on the eBird map.


The best way to follow the spring migration of Ruby-throated Hummingbirds is the map at hummingbirds.net, but if you also follow eBird you might notice that sightings posted there tend to lag a bit behind. This annual discrepancy became a full-blown controversy in 2012, when sightings reported to hummingbirds.net galloped far ahead not only of eBird but of any similar period since 1996, the year hummingbirds.net creator Lanny Chambers began tracking Ruby-throated spring migration.

-w-250The reasons behind the 2012 discrepancy had more to do with different birding styles than with that spring’s odd weather or the birds themselves.  To clear the air and build a bridge between the mainstream birding and hummingbird specialist communities, I wrote an analysis for the May 2014 issue of the American Birding Association‘s Birder’s Guide to Conservation and Community. Whether you’re not yet a member of ABA or missed that issue of the Birder’s Guide, you can read “Parallel Universes” for free right here (page 46).

Thanks to Birder’s Guide editor Michael Retter and all the hardworking folks who make ABA such a great organization, and to Lanny Chambers and his dedicated network of hummingbird watchers.

Are there studies on how red dyes affect hummingbirds?

Feeder solution colored with cherry juice concentrate

Hummingbirds don’t need a colored solution, but natural coloring from fruits and vegetables (in this case, tart cherry juice concentrate) is a far safer alternative to the petroleum-based dyes found in liquid food coloring and commercial “instant nectar” products.

Primum non nocere. [First, do no harm.]
—Thomas Sydenham, “The English Hippocrates” (1624–1689)

A recent visitor to the Field Guide to Hummingbirds Facebook page asked a question that comes up frequently in discussions of the use of petroleum-based food dyes in hummingbird feeder solutions:

Have any scientific studies been conducted to determine the effects of these chemicals on hummingbirds?

Some people are surprised to learn that the answer is an emphatic “NO.” Despite oft-repeated (and oft-debunked) urban legends that the San Diego Zoo, Audubon Society, or some other trustworthy source tested red dye on hummingbirds and found one or more specific effects (liver damage, kidney damage, cancer, tumors, “birth defects,” weakened eggshells, or, in some versions of the story, no harm at all), there is no evidence that any such testing has ever been conducted on hummingbirds by anyone anywhere.

Considering the challenges of such a study, direct testing of dyes on hummingbirds is not likely to happen:

  • Hummingbirds, like most wild birds, are protected by the Migratory Bird Treaty Act and various state laws, and animal research is subject to its own set of federal, state, and institutional regulations, so the first hurdle would be to get all the necessary permits and permissions to capture wild hummingbirds, confine them at a research facility, and perform lethal testing on them.
  • Getting the permits would require the researchers to prove that they could provide proper housing and care for the duration of the study. Hummingbirds are difficult and expensive to house and feed, and it could cost many thousands of dollars to keep dozens of them alive and otherwise healthy for the duration of testing.
  • The size and composition of the study population is very important. If the number of birds is too small, the results may not be clear, or critics may dismiss them as not statistically significant. If only one species is tested, critics may argue that the results may not apply to other hummingbirds. If only males are tested, critics may contend that the dye could affect females differently or not at all and therefore have little effect on populations.
  • To document the effects of dye consumption on the birds, the researchers would have to “sacrifice” and dissect them. It would be difficult to find qualified researchers interested enough in hummingbirds to perform such a study, qualified to undertake or supervise daily care of dozens of captives, and willing to kill them all to get the data. Imagine, too, how the hummingbird-loving public would react to learning that dozens of hummingbirds had been taken from the wild, dosed with dyes, killed, and dissected, even if the results might help to protect the health and safety of millions of other hummingbirds.

“Skeptics” who insist that such studies are required to “prove” that petroleum-based artificial dyes harm hummingbirds are setting the bar far higher than we do for our own health. No one in their right mind would suggest that we evaluate the safety of food additives, drugs, etc. by exposing human subjects to potentially harmful doses. Instead, we rely on the results of testing on lab animals and cell cultures to indicate whether and how various chemicals may affect human health.

Just because artificial dyes have never been tested on hummingbirds doesn’t mean they’ve never been tested. In fact, there are plenty of published studies on the effects of FD&C Red No. 40 and FD&C Red No. 3 to help us make a compelling case against exposing hummingbirds to high doses of these dyes, without taking the life of a single bird.* The real challenges are to increase awareness of this evidence among backyard enthusiasts and persuade manufacturers of commercial “instant nectar” products to use safer alternatives.

Unfortunately, the people who make money selling “instant nectar” products have proven extremely resistant to pressure from both hummingbird experts and the general public, and there are no regulations governing the use of human-approved food additives in foods intended for wild animals. Too many companies put profits ahead of everything, including animals’ lives and federal laws, but persistent, science-based outreach promoting responsible hummingbird feeding will help to shrink the market for artificially dyed “nectar” products and protect the health of the birds we love.



* One “cruelty-free” alternative for directly assessing the effects of dyes on hummingbird health is to look for dye residues and signs of related genetic/cellular/tissue damage in birds that are either found dead or die after being brought to wildlife rehabilitators. These sad cases have provided valuable insights into the diseases and parasites that afflict hummingbirds (see Hummingbird health: pathogens and disease conditions in the family Trochilidae. Loreto A. Godoy, Lisa A. Tell, Holly B. Ernest, J Ornithol (2014) 155:1-12. 
DOI 10.1007/s10336-013-0990-z).

Join me in Trinidad & Tobago!

I’m thrilled to have an opportunity to co-host (with my husband and colleague Tom Wood) a tour of Trinidad & Tobago June 18-26, sponsored by the Southeastern Arizona Bird Observatory and arranged by Caligo Ventures. This island nation off the Caribbean coast of South America is home to over 400 species of birds, including 19+ species of hummingbirds, as well as a variety of other tropical wildlife from dainty butterflies to gigantic Leatherback Sea Turtles. Here’s a short introduction to the world-famous Asa Wright Nature Center, where the group will stay for five nights:

I’ve wanted to visit Trinidad and Tobago for over 30 years, ever since I read David Snow‘s studies of the White-bearded Manakin (Manacus manacus) at Asa Wright Nature Centre after returning from my first trip to Belize. I had spent many hours studying the previously undocumented courtship behavior of the closely related White-collared Manakin (Manacus candei), and Snow’s landmark work helped me understand what I had observed.

There are still spaces available on this tour for a few enthusiastic nature lovers (the limit is 10 participants). For more information, visit SABO’s Trinidad & Tobago info page or contact Caligo Ventures at 800-426-7781 or by e-mail.

Nesting material for hummingbirds

Female Broad-billed Hummingbird collecting nesting material

A female Broad-billed Hummingbird collects nesting material provided by her host. (Click to enlarge)

Along the southern Pacific Coast and in the lower elevations of the Desert Southwest, Anna’s and Costa’s hummingbirds are already nesting or will be shortly. You can help by providing safe nest material such as clean pet hair, short lengths of white or light-colored wool yarn or roving, natural wool fleece, natural cotton or wool batting, and down salvaged from worn-out garments or comforters.

Short fibers (1/2″ or less) are easier for females to take and use and less likely to get wrapped around tiny feet. Hummingbirds prefer white and very light colors, but other birds may take darker fibers. Avoid synthetic fibers, dryer lint (which may be too absorbent and contain fabric softener residues), and hair from pets treated with flea/tick products.

Stuff the fibers moderately tightly into a clean onion bag or suet cage and hang the dispenser near your feeders, then sit back and watch the fun!