Ever since I saw that first ruby-throated hummingbird feeding on a trumpet vine in my mother’s garden on Cape Cod I have had a fascination with hummingbirds. In recent years there have been a number of scientific papers published about both their evolution and physiology which have made me even more entranced with them.
Hummingbirds are the New World’s birds of paradise on a tiny scale. They can have extravagant plumage such as the long-tailed and violet-tailed sylphs, while some of the other plainer species may have a bubbly complex songs or a spectacular display, and myriad behaviors. There are 17 species of hummingbirds that breed in the United States—a fair number, but as one heads south of the border, the species diversity increases dramatically. In the neotropics hummingbirds species figure to literally hundreds of species. Current thought is that there are between 330 and 340 hummingbird species on Earth, depending on one’s taxonomy. Evolutionarily, hummingbirds are relatively new, splitting from the swifts and tree swifts in Europe some 40 million years ago starting their own lineage, then thought to have come to the new world across the Bering land bridge, arriving in South America 22 million years ago. From there, apparently, they radiated through North America. and east to the Caribbean. The family continues to diversify at a rapid rate. One paper suggests that without human interference of habitat alteration and loss they could evolve to more than 700 species!
Like many taxa, it is in the Andes of South America, a region of high peaks, canyons and deep valleys containing myriad micro habitats, that hummingbird diversity has taken off; as many as 25 species can be found in one locale, perhaps 140 species can be found in the Andes alone.
Occurring from sea level to the high Andes at more than 15,000 feet, hummingbirds have uniquely adapted to combat cold and thin air in combination with their small size and high metabolism. Even here in the U.S. on cold nights, they can fall into a hibernation mode called torpor, and lower their heart rate from around 1,000 beats per minute down to 50-180 BPM, and lower their body temperature from 104 ° F to 65° F. When in this state they almost seem dead, taking 20 minutes to “wake up.” Hummingbirds of the high Andes have another adaptation: their hemoglobin can bind more readily to oxygen, so they can utilize more easily air with a low oxygen ratio, enabling them to forage and live efficiently at high altitudes. The hillstars have a third behavioral adaptation to deal with cold nighttime temperatures at high elevations:, They make a huge, bulky nest of alpaca, llama and sheep fur, nestled under an overhang.
A few years ago I went to the Andes in Ecuador for a month to look at hummingbirds. It was not a typical birding trip trying to see as many species as possible. I went to only three places not far from Quito. I wanted to spend time in each area watching and sketching hummingbirds, and, of course, whatever else I might see. My first stop was in the Tandayapa Valley. I stayed at Bella Vista lodge, in Northwestern Ecuador, at an elevation of 5,000-7,200 feet. Like most lodges in the area, it had an array of humming bird feeders to watch, fruiting and flowering trees around the property and numerous trails to hike as well as the main, dirt road through the valley. By far my favorite hummingbird here was the endlessly entertaining and cute booted racket-tail.
Although I did spend a good deal of time watching the feeders at Bella Vista, I really wanted to see what and where the hummingbirds were feeding away from the feeders.
My second stop was just over the Andes through Papallacta pass to Guango lodge on the east side. There is so much speciation in South America that each elevation and each slope of the Andes hosts a different avifauna. There is, of course, some overlap here and there, but frequently, one species at different locations are distinct subspecies.
My visit to Guango was only for a couple days, on route to my final long stay at San Isidro. Guango is at 8,858 feet elevation and is one of the easiest places to see the fantastic sword-billed hummingbird. No matter how many photos or videos one sees of this odd hummingbird, there is nothing like seeing it in life as it flies down and backward after feeding on the huge bell-like Burgmansia sanguinea, or angel’s trumpet: The bill seems endless. Apparently most Burgmansia are moth-pollinated, but this species, with red-rimmed flower,s is pollinated by the sword-billed hummingbird, one of many examples of the co-evolution between flowering plants and hummingbirds found in the neotropics.
The east slope of the Andes at an elevation of 6,800 feet. Here there were several of the same species that occurred both at Guango and at Bella Vista, such as the abundant collared inca
Hummingbird tongues have long, lengthwise side grooves. It was thought that through capillary action nectar was drawn up along these two grooves, but apparently the skin is actually closed around the nectar, thus capturing it. I imagine when one sees a hummingbird sitting with its tongue flicking in and out as in the above picture it is cleaning out those grooves
I frequently saw feeding sylphs in the crowns of small shrubs and trees when I hiked around San Isidro.
All too soon my month with the hummingbirds (and other birds too of course) was over.
I have mentioned only a few the numerous species of hummingbirds one encounters in the Andes. I spent my time in only three places and saw upwards of 50 species, providing me with just a taste of the extraordinary diversity of hummingbirds found in the Andes.
There is an ever increasing interest by scientists in understanding more fully hummingbirds’ remarkable physiology, their evolution and their role as pollinators in the tropics. I look for ward to reading the results of their studies and watching, drawing and painting more hummingbirds in the future.
About the Author
Sophie has travelled from the Antarctic to the Arctic and numerous places in between to both draw and study birds. She co-authored and illustrated a Guide to the Birds of Mexico and Northern Central America (Oxford University Press), a Field Guide to the Marine Mammals of the Pacific Coast (University California Press) and written and illustrated three children’s books about research projects she has worked on (Houghton Mifflin Co). One of her favorite pastimes is to sketch wildlife in the field. She is a director of Oikonos: ecosystem knowledge, a research associate of Point Blue and an occasional employee of NOAA’s South West Fisheries Science Center.