Leaving on the hummingbird highway

There are only two hummingbirds remaining near the cabin today. They made brief visits to one of my two feeders and now-scraggly hanging basket of flowers. This scene is a far cry from a week or so ago, when resident broadtails were crowding the feeders, draining them in a day. They were getting ready to migrate, and now most of them have, flying off on their long journey to the central highlands of Mexico, where they’ll spend the winter. It seems so quiet. During the summer, when I slept with windows open, I woke up to their chirping/whistling/buzzing as they began to soak up sugar-water carbohydrates before a morning of insect-catching. Now if I want to hear their distinctive sound, I’ll have to go online for a brief recording; until, that is, they and I return next spring.

Next spring, they’ll be here first, at least the males will, searching for a territory. They arrive in Florissant in early May. Hardy little birds, as snow is not uncommon in the high country in May. I’ll probably arrive a few weeks to a month later. I too will migrate this fall—north to Denver, where I’ve had a small apartment since last fall. Though I enjoy city life very much, I truly love this country cabin nest, where I spent most of this summer. The hummers’ departure reminds me that I’ll be leaving soon too—a bit later, though, probably mid-October.

For me and the broadtails—which among all hummingbird species live at the highest elevation—summer at 8700 feet (2650 meters) provides a perfect habitat. There are nectar-filled wildflowers and a small cottonwood grove—food and proper nesting shelter for them, and lots of beauty for me. Wildflowers were plentiful this year due the above-average spring rainfall, but even in years when they aren’t, the returning hummers can count on a network of human servants who run up a shocking sugar tab at the supermarket on their behalf.

Though I’d love to have a true scientific mind, I don’t. Mornings, coffee cup in hand, I’ll watch the birds at the feeder, admiring their beautiful colors—the metallic blue-green of the females’ backs and the bright red gorget (think gorgeous) of the males, sparkling in the sun.

Here’s an illustration of a male and female by Arthur Singer from The Life of the Hummingbird (A.F. Skutch, 1973).

After watching these birds for awhile, likely as not, I’ll then cross the living room to watch the clouds through the sliding glass doors or head out to the greenhouse or go on a walk with Linda and her dogs. In the early evening, I do pretty much the same kind of viewing, as likely as not, as the broadtails arrive to fuel their metabolism for a cool night in torpor at high altitude. 

By scientific mind, I mean curiosity, passion for learning, observational skills, and patience. To the extent that I have those qualities, they show up in other areas. Fortunately, there are many bird lovers, trained scientists and citizen-scientists who have contributed knowledge I would most likely never discover on my own.

One of the first studies to support the idea that a hummer can eat twice its weight in sugar every day, was done by Althea R. Sherman. In 1907, from her doorway in Iowa, she trained free ruby throats to drink a sugar solution placed in an artificial flower. Measuring carefully, she found that a single bird drank syrup containing from 4.5 to 5.8 grams of sugar. She misjudged the average weight of a bird, however, leading to what was later shown to be an overestimate. Years later another experimenter found that a bird could drink twice its weight in syrup, but less than half its weight in pure sugar. 

During the height of my hummers’ feeding frenzy, I wondered if I were creating sugar addicts, like encouraging teenagers to gulp soda instead of water or juice. Fortunately, experts have dispelled that fear. According to the popular website, hummingbird net, a solution of 1 part sugar to 4 parts water is very similar to the sucrose content of nectar. Even more reassuring was the fact that ordinary white sugar—the bane of human health—is the best choice for hummers. Turbadino, a kind of raw sugar sold in health food stores, may contain a toxic level of iron, while honey ferments too rapidly.

Scientists have learned a lot about gender in hummingbird life also. Female broadtails spend most of their nesting time incubating and then feeding their (usually) single clutch of two eggs. Once hatched, the helpless nestlings need frequent attention before they’re able to fly away 21-26 days later. My broadtail females are definitely “sistuhs doin’ it for themselves”, as males make no pair bonds with them and play no part in chick-rearing. The males’ summer is spent in guarding their feeding territory.  They’re known for their dazzling displays during mating, when 2—3 males form a group called a lek and fly in loops through the air. Females make their choices and mating commences. As the females enter motherhood, the males continue trying to mate with other females. Who is the most successful? I wonder. Most aggressive? Prettiest gorget? Surely there’s a study somewhere that answers that question.

I should mention that I have other summer visitors in addition to the Broadtails. Rufous hummers show up at my feeders in early July. 

They’re known as an aggressive species, seeming bullies who try to dominate the feeders. I hate to speak badly of a bird, but….by July I’ve bonded with my innocent broadtails and find myself feeling quite hostile to the newcomers. I’m not sorry that they’re the first to leave as summer slips by. Scientific migration studies have given me some respect for them, however. They nest as far north as Alaska (!), migrating south, and then continuing on south after their summer stay here—adding up to the longest range of any of the more than 300 identified hummingbird species. Most of them live in the tropics and all are native only to the Western Hemisphere.

Most of the hummers spending the summer here are well on their way to Mexico now. I trust my two stragglers will feel the same hormonal/seasonal tug very soon, as signs of fall are already here—aspens turning gold and night temperatures dipping into the 40sF. According to Bill and Ella Thompson of Enjoying Hummingbirds More (1992), “At least one species of hummingbird is likely to fly over any garden in any state in the US or in southern Canada”. That comforts me as I think of “my” hummers on their aerial highway. Perhaps they have a network, a kind of overground railroad of backyard feeders, familiar to the older birds who’ve made the journey before. I hope so. Their August nectar-guzzling here won’t be enough to get them through the whole trip. Incidentally, hummers live an average of 3–4 years, although a 12-year-old banded broadtail was once observed in Colorado. That’s the current age record.

Later this month The Third Annual International Hummingbird and Birds of Guanajuato will be held in Mexico, in San Miguel de Allende in the State of Guanajuato. There will be festival events for the public in this city where I had the good fortune to sojourn for some extended time during two recent winters. I wish I could be there this year, if only to see the surprise on the tiny faces of any of “my” birds in the vicinity :). There will also be a conference of scholars and students ready to report their latest findings. That’s another comfort—that with human impacts on habitat everywhere, there are scientists and conservation activists monitoring the situation. 

Broadtail hummingbirds are not endangered at this point. With the growth in citizen science and the availability of online data bases, information is emerging that birds are adaptable, perhaps more than we thought. For example, a recent study showed that calliope hummers have been sighted 350 miles off their traditional migration routes. In The Human Age (2014), Diane Ackerman notes an Audubon Society study finding that roughly half of 305 North American birds are wintering 35 miles north of where they wintered 40 years ago.

With my own upcoming migration in mind, I’ve already started making notes for next year, when I hope to spend, once again, much of the summer here at Little Horse. More hummer-friendly flowers near the cabin, for one thing. Meanwhile, I’ll continue to read. One of the most interesting sites I’ve found is birdwatching bliss. It’s maintained by Sonia, an avian scientist who lost her full-time employment in a budget cut. (Fortunately, her husband kept his.) Working part-time as a wildlife technician now, she’s put her passion into this website, which offers concise, up-to-date information about many different birds. Perhaps by next year I’ll be a little closer to having a scientific mind after all.