Feeder Solution Evolution Part I: The basics

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.

A young White-eared Hummingbird drowses in the sun

A young White-eared Hummingbird drowses in the sun.

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.).

See this post for a more comprehensive list.

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.

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).

Related posts:

Search of the Week: “if refined sugar is so bad for us, then why do we feed it to hummingbirds?”

Search of the Week: “is molasses ok to feed hummingbirds”

Beet juice in hummingbird feeders? NO!

Search of the Week: “can I give hummingbirds mountain dew”

Geography tutor needed, apply at London (Ontario) Free Press

From “Hurricane relocates hummingbird”:

Probably the most interesting bird spotted in Nova Scotia after the passage of hurricane Earl, was a Calliope hummingbird from the American western mountains, where they are uncommon at best…

How the southwestern hummingbird ended up in Nova Scotia, is a mystery. It might have been migrating south to its wintering grounds in north west Mexico when it got caught up in Earl’s vortex.

Or not.

A couple of minor problems with this scenario:

  • Hurricane Earl never got within 1000 miles of the Calliope Hummingbird’s normal migration routes to its wintering grounds in southwestern Mexico.
  • Any Calliope Hummingbird sucked up by one of those rare Rocky Mountain hurricanes would not survive to be dropped off 2000 miles away in Nova Scotia unless the winds also transported a bunch of uprooted nectar plants and/or hummingbird feeders along with farmhouses, livestock, runaway schoolgirls, and psycho dog-hating neighbor ladies on bicycles. Oh, wait… that’s tornadoes.

Hurricanes almost certainly do “relocate” hummingbirds on occasion. If this was such an occasion and not just a coincidence, the most logical scenario is that the bird had already migrated to the Atlantic Coast before it “got caught up in Earl’s vortex.” Still highly unlikely because of problem #2 above.

Of course, fall migration is a normal time to find “wayward” birds almost everywhere in North America, even in the absence of hurricanes (or tornadoes). Calliope Hummingbirds are Canadian birds, too, nesting in British Columbia and southwestern Alberta, so this one could have traveled east-southeast completely under its own power, never coming anywhere near Earl’s path until it arrived in Nova Scotia nor even straying out of Canadian airspace.

Rant over. Please resume your normal activities.

Search of the Week: “are humming birds cold blooded”

One reason I like WordPress so much is that it allows me to monitor not only how many people are visiting my blog but how they find it. Some pretty interesting searches bring people to Life, Birds, & Everything, so I thought I’d highlight one of these every now and then (hopefully weekly).

This week’s featured search is a question whose answer has already been alluded to in the post “Rescuing” baby hummingbirds. The full answer is more complicated, though, and here it is:

Hummingbirds hatch naked and cold-blooded (poikilothermic, body temperature dependent on the surrounding environment). They don’t become warm-blooded (homeothermic, capable of maintaining a stable body temperature regardless of environmental conditions) until their feathers mature enough to create an insulating layer over their skin. They can return to a limited form of poikilothermy as adults when they need to conserve energy, entering the state of torpor overnight or under severe stress. This qualifies hummingbirds as heterotherms.

“Out the Window” preview

Here’s a snippet from the latest installment of my “Out the Window” column in the November/December 2010 issues of WildBird magazine:

Every year they make their way south. Some are impatient, departing before the first frosty flakes fly. Others seem reluctant to leave, toughing it out until their summer homes are buried in snow. Many return to the same spot every winter, often flocking with their summer neighbors from the same northern communities. A few aren’t so predictable, roaming far and wide wherever winds or whims carry them.

Though they don’t all have feathers, they all qualify as “snowbirds.”

Not a subscriber yet? This link to Amazon.com will get you a full year (six colorful, information-packed issues) for just $12.99, and your purchase will benefit the Southeastern Arizona Bird Observatory. You’ll find this and other birding magazines, field guides, feeders and accessories, seeds for hummingbird-friendly plants, and more at SABO’s online shop, The Trogon’s Nest. Single copies of Wildbird are also available at newsstands and bookstores.

Rufous vs. Allen’s

No, it’s not the fight of the decade—it’s one of the thorniest bird ID problems in North America. Right now little orange and green hummingbirds are sweeping across the continent on their way south. Most are traveling through the Pacific and Intermountain flyways and will end up in Mexico, but a significant minority (hundreds) will stray east of the Rockies to delight and confuse migration watchers and winter hummingbird aficionados.

adult male Rufous with rufous back

An unambiguous adult male Rufous. If the back is less than half green (including entirely rufous), you can safely call it a Rufous without seeing the tail. (Note the green crown, which is normal, and the green gorget, which is an artifact of the angle.)

One of the most commonly repeated myths about hummingbird identification is that an orange hummingbird with a green back is an Allen’s. I was told this by a local birder on my first visit to southeastern Arizona in 1978, and on her authority I put Allen’s Hummingbird on my life list based on the little orange and green female-plumaged birds swarming around her feeders. There it remained until 1988, when I moved here and began to acquaint myself with the true depths of the problem.

Once I realized that in both Rufous and Allen’s all females and juvenile males have green backs, I scrubbed Allen’s from my life list. Over the next few years I learned through banding experience that a small percentage of adult male Rufous have enough green on their backs to be easily confused with Allen’s.

Yes, I know you don’t want to hear this, but take your fingers out of your ears and look at the photo at right (you may click the image to embiggen).

Notice the notched tip of R2 (the next-to-center tail feather)? Diagnostic for Rufous. Sorry.

The only safe, accurate way to distinguish between Rufous and Allen’s in any and every plumage is by the shapes of the tail feathers. You can see these when the birds fan their tails in combat or preen them. In Allen’s, all of the tail feathers are narrower than in Rufous, most noticeably the outer three. In Rufous, R2 has that distinctive notched tip in adult males, expressed as a “pinched” tip in most (but not all) adult females and juvenile males. To clarify, here are silhouettes of the adult male tails:


And here are juvenile males (note the green backs):

You can see how extremely subtle the differences are in juvenile males (adult females are similar)—not something you’re usually going to see in the field. Juvenile females are the most “generic” and can be impossible to identify even in hand. This is why it’s so important to determine the age and sex of the more difficult hummingbirds before you try to assign them to species. If it’s a female or juvenile male Rufous or Allen’s, best to fuggedaboudit unless you can get photos of the fanned tail.

It’s very common for orange-and-green hummingbirds observed east of the Rockies to be called Rufous in the absence of any documentation, based simply on expectation. Sometimes “probable Rufous,” sometimes “Selasphorus species” or “Rufous/Allen’s” (which we’ll get to in a moment), but all too often just “Rufous.” This can give the impression that an identification has been confirmed when it hasn’t, leading to much rarer birds (Allen’s, Broad-tailed, Calliope) being overlooked. A look at the range maps in A Field Guide to Hummingbirds will show you why it pays to know all of the Rufous doppelgangers’ field marks and check them out for yourself (documenting with a camera, where possible).

More conservative birders may go a bit too far the other way, calling any orange-and-green hummingbird “Selasphorus species” even when Broad-tailed (the oft-forgotten member of the genus) is readily ruled out. Once Broad-tailed has been eliminated from consideration, the most accurate label to use is “Rufous/Allen’s.” You’ll find this as an option on eBird and “Allen’s Hummingbird/Rufous Hummingbird” in the Christmas Bird Count historical results. If any orange-and-green hummingbirds occur within your local CBC circle but the compiler doesn’t use “Rufous/Allen’s” on tally sheets or in the final reports, please encourage them to do so.

Addendum 1: I’ve created galleries on Flickr with comments on each photo pointing out the key field marks that identify each bird as Rufous or Allen’s.

Allen’s gallery

Rufous gallery

Addendum 2: Since this post was published, Calliope Hummingbird has been moved to the genus Selasphorus, making “Selasphorus sp.” even less specific than it used to be.

Addendum 3: Though the Sibley Guide illustrations point out an orange “eyebrow” on the side view of the adult female Allen’s but not on the (virtually identical) adult female Rufous, this is a field mark distinguishing Rufous and Allen’s from the gray-faced Broad-tailed and Calliope, not from each other.

Addendum 4: Clearly Rufous by the widths of all the tail feathers and the distinctive shape of R2, but with green all the way to the uppertail coverts:


* * * * * * * * * *

On a historical note, this time of year—Rufous time—always brings to mind the late Ken Kesey and the Merry Pranksters. Orange and green were the heraldic colors of these counterculture court jesters. Toward the end of Ken’s life, one of the networks came to his Pleasant Hill, Oregon home for an interview. Ken took them out onto his property to show them the Pranksters’ original bus, “Further” (also spelled “Furthur”). When they reached the bus, Ken noticed a small shape buzzing around inside: a Rufous Hummingbird. Ken gently corralled the terrified creature and carried it to freedom outside Further’s door. I cried.


Hummingbird rescue

My husband and I had a little guest in our home for a couple of days last week: a fledgling female Black-chinned Hummingbird who had lost the primary feathers on her right wing.

fledgling female Black-chinned Hummingbird in her "hospital box"

"Miss Thing" in her temporary quarters

The feathers, which were probably pulled out in an encounter with a predator, were already growing back, indicating that she was still being fed by her mother while she recovered from the injury. Lucky girl, but not so lucky when she ended up grounded on a sidewalk. But lucky again when she happened to fall right in front of one of our Bisbee neighbors, who gently scooped her up, took her home, and gave us a call.

Though we don’t do wildlife rehab anymore, we were able to find a rehabilitator in Tucson who specializes in hummingbirds and chauffeured her there the second morning after her rescue. Such a short time in our home, but she won my heart with her fearlessness and determination.

Here’s hoping “Miss Thing” makes a full recovery and returns to her Bisbee birthplace next spring.

Incredible hummingbird connection: Florida to Alaska

Hummingbirds wintering in the southeastern United States were long written off as hopelessly lost and doomed, but banding studies have shown them to be far better oriented than we could have imagined.

A new record was set this week by a second-year female Rufous Hummingbird banded January 13, 2010 at a private home in Tallahassee, Florida by Fred Dietrich, a bander with the Hummer/Bird Study Group. The bird was recaptured on June 28 in Chenega Bay, Alaska by Kate McLaughlin, a subpermittee working under master hummingbird bander Stacy Jon Peterson of Wasilla, AK. Chenega Bay is a tiny community on Prince William Sound; its residents are predominantly Native Alaskans of the Chugach Alutiiq group. Kate and her husband Andy have been banding hummingbirds since 2008, and this is their first recapture of a bird wearing another researcher’s band.

According to Google Earth, the minimum distance between the two sites is approximately 3500 miles. The previous record was approximately 2200 miles, set by a Rufous banded in Lafayette, Louisiana by Dave Patton and found dead on Vancouver Island, British Columbia.

Congratulations to Fred and Kate on this incredible connection!

Perch hypothermia rides again

You cannot reason a person out of a position he did not reason himself into in the first place.

— attributed to Jonathan Swift, 1667-1745

It was too good to last. After four years of keeping under the radar, Montana wildlife rehabilitator Judy Hoy is once again warning the public about the evils of perches on hummingbird feeders.

Briefly, Hoy believes that hummingbirds that perch to feed on cold sugar water are at risk of hypothermia. From her recent article in the Great Falls Tribune:

If the outside temperature is below 50[° F.] and the sugar water is cold, the birds can become completely hypothermic after drinking two crops full without flying. They then fall to the ground and eventually die from cold and lack of food or are eaten by magpies, cats or other predators.

Hover-feeding isn’t a problem, she says, because the muscle action helps to warm the bird’s body.

She claims that hummingbirds, especially Rufous, are “dying by the thousands every spring” from this phenomenon and is understandably frustrated that hummingbird researchers, feeder manufacturers, and government agencies won’t take her seriously. In this latest article, our self-styled Cassandra gets a little testy:

You may get the impression from this post that I am running out of patience with stupidity and I am!

Same here, Judy.

By her own account, Hoy started her anti-perch campaign in 1985. A quarter of a century is plenty of time to gather an enormous amount of support for her claims, so where is it? Despite repeated requests from skeptics, she hasn’t produced any photos, videos, necropsy results, or other objective evidence to demonstrate that feeder perches cause hypothermia in otherwise normal, healthy hummingbirds. Instead, she continues to rely on anecdotes, opinions, and misinterpretations of cherry-picked scientific research, ignoring more relevant research that refutes her claims.

Over the same 25-year period, people who host wintering hummingbirds have amassed hundreds of thousands of observations of birds perching to feed when the temperatures of both the air and the sugar water are well below freezing (20 degrees or more colder than Hoy’s hypothetical hypothermia threshold), and showing absolutely no ill effects. Additionally, hummingbird banders in the southeastern U.S. have documented hundreds of hummingbirds, including Rufous and Calliope, returning year after year to the same wintering sites. Many of these birds take their first sips of frosty sugar-water every winter morning while resting on feeder perches. Though this doesn’t “disprove” Hoy’s perch hypothermia claims, it does strongly suggest that it’s at worst an extremely rare cause of mortality.

Anna’s Hummingbird in my southeastern Arizona yard on a snowy day

None of this seems to make a dent in Hoy’s belief. She responded to these challenges by adding increasingly elaborate and often conflicting justifications for the lack of independent verification: most people never see hypothermic hummingbirds because predators get them first, it happens mostly in “Canada, North Eastern States and…Western Montana,” Rufous are particularly cold-sensitive (!), different species have significantly different “thermodynamics,” pesticides and herbicides sprayed in her area damaged their mitochondria and/or thyroid function.

Unlike Hoy, I don’t expect anyone to take my word on something without evidence. That’s why I wrote a detailed analysis of perch hypothermia way back in 2006, after a message she posted to an online discussion group was forwarded to other groups by well-meaning participants. At Hoy’s request, I sent her all of the evidence refuting her claims, with faint hope that we might lay perch hypothermia to rest once and for all. No such luck. Like True Believers® in so many other crackpot ideas (young-earth creationism, alien abductions, “rods,” homeopathy, etc.), Hoy’s faith is unshakable.

The latest version of her story adds a new and ominous detail, but one that’s easily debunked. In the Great Falls Tribune article, she says:

…Rufous and Calliope are now on Audubon’s red list.

Nope. Both species were listed on the 2002 Audubon Watchlist as yellow (declining), not red (declining rapidly). The 2007 Watchlist includes only the Calliope, still in the yellow category. It’s disappointing, but far from surprising, that even her “new” information is both overstated and outdated.

Removing perches from hummingbird feeders is unlikely to do any significant harm, but it’s equally unlikely to do any significant good. Birds need well-informed friends to help protect them from real and growing environmental threats, so I hate to see the same alarmist claptrap making the rounds over and over and over. Cut the perches off your feeders if you like, but don’t let misinformed prophets of doom distract you from doing things that actually help hummingbirds:

And if you’re still worried about “perch hypothermia,” make your feeder solution richer (3:1 instead of 4:1) during cold weather so that the birds have to take in less cold solution to get the same amount of energy.

Ecuador Part 1: In which a woodpecker brings tears to my eyes

Red is a very emotional color. I say this in my own defense, since even the most ardent bird lovers are seldom moved to tears by woodpeckers. I can imagine the crustiest of field biologists blubbering like a baby at spotting an Ivorybill, and who wouldn’t feel at least a tingle when a Pileated swoops in to scatter lesser birds from a feeder? But woodpeckers of modest size, average shape, and non-endangered status don’t usually inspire spontaneous outpourings of emotion.

Getting to Ecuador was a long, grueling process, so Pam, Tom, and I didn’t emerge from our cozy rooms at San Jorge Quito that first morning until it was well light. Mist shrouded the lush, green landscape as we ambled along the trails, stopping every few steps to give our lungs a chance to strain oxygen from the thin Andean air.

Ahead an incandescent blur blazed across the trail. “RED!” was all I could manage as I fumbled for my binoculars. The blur stopped abruptly at the base of a small tree, bringing its true form into focus. From studying the field guide, I recognized it instantly.

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