Tiny, pugnacious, and jewel-like, hummingbirds are pretty easy to attract to a garden and fun to have around. Probably the most specialized nectar-eating animals, a careful look at hummingbirds provides a window into the elegance of adaptation in the natural world.
not on the branch
in the air
Not in the air
in the moment
Hummingbirds belong to the avian family Trochilidae and their closest relatives are the equally fascinating swifts. Hummingbirds are small (2-20 grams), with long narrow bills, and small saber-like wings.
Males (and occasionally females) often have a colorful gorget (see sidebar): small, stiff, highly reflective, colored feathers on the throat and upper chest. These shiny feathers and others around the head may look sooty black until a hummer turns its head to catch the sun and display the intense metallic spectral color.
The Smallest Birds: The bee hummingbird of Cuba is only 1.95 grams, which means that theoretically 16 could be mailed first class for 39 cents. The calliope hummingbird, the fourth smallest bird, weighs in at a whopping 2.5 grams (less than an ounce) and can be found in the mountains of western North America.
The Tiniest Egg: The smallest birds come from the smallest eggs. Makes sense. But how small? The one to two eggs in a ruby-throated hummingbird clutch are about as tiny as peas and are placed in a walnut-shell sized cup woven from spider webs and plant material.
The Avian Helicopter: Hummingbirds and swifts are able to stroke with power both on the down- and up-beat of a wing flap. Their power and small size allow tremendous agility in flight. In fact, hummingbirds are the only vertebrates capable of sustained hovering—staying in one place during flight—and they can fly backwards and upside down as well.
To their maneuverability, hummingbirds add speed and stamina. Hummingbirds have been clocked at close to 30 mph indirect flight and more than 45 mph during courtship dives. Migratory ruby-throated hummingbirds have no problem flying 18 to 20 straight hours to cross the Gulf of Mexico, powered by their fat stores and given a bit of help from winds.
Life in the Fastlane: A ruby-throated hummingbirds heart beats from 225 times a minute when the bird is at rest to more than 1,200 times per minute when its flying around. Its wings beat about 70 times per second in direct flight and over 200 times per second while diving.
Asleep on the Job: Hummingbirds are one of the few groups of birds that are known to go into torpor. Torpor is a very deep sleep-like state in which metabolic functions are slowed to a minimum and a very low body temperature is maintained. If torpor lasted for long periods, we would call it hibernation, but hummingbirds can go into torpor any night of the year when temperature and food conditions demand it.
Hummingbirds are the masters of torpor because the have to be. Their feathers offer poor insulation and they have incredibly high metabolic demands. Torpor allows them to check-out physiologically when they cant maintain their normal 105° body temperature.
The almost 340 species of hummingbirds are entirely restricted to the New World, where they can be found from Tierra Del Fuego to southern Alaska and from below sea level deserts to steamy tropical forests up to 16,000 feet in the Andes of South America.
Most species live in the tropics, and while 17 species regularly nest in the United States, many of these are found close to the Mexican border. Most areas in the U.S. have one or two breeding species, and only the ruby-throated hummingbird nests east of the Mississippi.
From left to right, the coppery-headed emerald, purple-throated mountain-gem, and violet sabrewing, are three of the many species of hummingbirds found in the tropics. © Karen Sirna
Their high-energy lifestyle compels hummingbirds to locate reliable food resources. Feeding on flowers puts hummingbirds at the mercy of the flowering seasons of the plants upon which they depend. Hummingbirds solve this by being very mobile and their movements are often shaped by the changing pattern of flower production over time.
In the western U.S., hummingbirds migrate through the lowlands in the spring and return by way of the mountains in the summer to track the intense blooming of annual plants in meadows and—moving ever-higher up the mountain as the summer progresses.
Hummingbirds don't always depend entirely on flowers. During the breeding season, in particular, hummingbirds hover mid-air and catch small flying insects to eat and feed to their nestlings.
In northern and high-elevation areas, hummingbirds depend upon sap-wells of woodpeckers known as sapsuckers. The woodpeckers are able to keep the sugary sap of trees flowing and the hummers sneak in and take advantage of the woodpeckers' work.
Hummingbirds are for the most part unsociable. In fact, the adjectives pugnacious and feisty are often appropriate. When more than one hummingbird is around, it is often a scene of repeated high-speed chases. In fact, male and female hummingbirds do not form a pair-bond after mating and the female is left to care for eggs and chicks alone.
Hummingbirds do not need the help of other hummingbirds, either to locate food or fend off predators. Other hummingbirds are competitors for the flower nectar upon which they thrive. The help that a male might provide a female does not outweigh the burden of having a male around competing for food.
What is all this fighting about? Plants take time to secrete nectar into their flowers. In an ideal world, hummingbirds should time their visits to flowers to take advantage of a full load. But they wait to feed at a flower at the risk of other hummingbirds beating them to the punch. It is therefore worth the effort for hummingbirds to chase away competitors so they have access and control of their favorite flowers.
In many cases, hummingbirds defend small territories around a favorite flower patch, and do so even during brief stop-overs for refueling during migration. Where many species live together, the large species attempt to dominate flowers and get the biggest drinks of nectar and smaller species try to sneak in for a few sips.
About the closest hummingbirds come to being social is in the tropics. The males of a small number of species form leks, places where they gather for months at a time and sing their scratchy hummingbird songs in an effort to attract females. The females are attracted to the leks and the males then compete for the opportunity to mate.
To be evolutionarily successful, flowering plants usually must have their pollen carried from the stamens of one flower to the pistil of another so pollination occurs. This is accomplished in myriad ways. Some plants broadcast copious clouds of pollen that is carried by the wind to settle on cars, our front porch, in our lungs, and occasionally on a plant of the same species.
Many other plants have evolved to be more efficient by producing few pollen grains and attracting specific kinds of animals. By providing a nectar reward in a flower that keeps out a lot of animal competitors, there is a good chance the pollinating species will search out another like flower and pollination will occur.
Flowers that attract hummingbirds:
This sage flower attracts a hummingbird with its bright red color. The hummer's long bill can reach the nectar at the end of the flower tube. Note the stamens protruding from the tip of the flower, they will deposit pollen on the forehead of a hummer as it feeds.
Most hummingbirds are not super specialized and will deign to feed at a pretty wide variety of flowers, preferring the hummingbird flowers described above. However, throughout the tropics are examples of very tight coevolved hummingbird-flower relationships in which the bill of the hummingbird fits the highly modified flowers almost like a key that opens a lock.
The life of a hummingbird consists of a relentless search for food. In areas settled by humans, the flowers that hummingbirds have evolved to hunt down and suck dry often disappear.
The good news is that the lost natural food sources can be easily replaced by planting the right plants and providing sugar water in hummingbird feeders.
Some good hummingbird plants include:
This perennial blooms in midsummer and grows about three feet tall. There are many varieties of colors and sizes available at nurseries. The variety Jakob Kline is resistant to powdery mildew.
A red spike of flowers arises from the basal leaves of this perennial in late summer. This plant tolerates some shade and prefers a moist soil.
A tall, vigorous vine, the large flowers are very attractive to hummingbirds. The pictured variety has yellow flowers but most often they have red flowers.
This well-behaved vine flowers profusely in April and May and then sporadically throughout the summer. With the return of cooler weather in the fall, it flowers heavily again. The pictured variety has yellow flowers but they are usually pinkish-red.
This perennial blooms from April to June and grows about one foot high. It tolerates some shade and likes to grow amid rocks.
More than half of the species of hummingbirds live in the tropics. Even our favorite backyard species migrate to the tropics, where they spend the greatest portion of the year. In the tropics, hummingbirds often move up and down mountains and between arid and moist habitats to keep up with where the trees and shrubs are flowering.
Coffee is often grown halfway up tropical mountains, the cross-roads for the myriad species moving to find flowers. When grown under a diverse canopy of shade trees, coffee plants, the trees that shade them, and the plants that grow on the trees provide a diverse smorgasbord of flower resources.
It is no wonder that shaded coffee farms can support impressive numbers of hummingbird species. In one coffee-growing region in Peru, Smithsonian Migratory Bird scientists recorded 24 species over the course of a year. Ruby-throated hummingbirds are abundant in coffee farms in Mexico and Central America during their stay in the tropics.
By drinking certified Bird Friendly® coffee, you help guarantee that coffee is grown in farms that feature the flowers that hummingbirds depend upon.
The male ruby-throated hummingbird's throat normally appears black (top).
But when the light strikes it at the right angle, it changes to a brilliant red color (bottom).