Hummingbirds belong to the family Trochilidae, native to only the Americas. They are the third largest bird family, right after the tyrant flycatchers and tanagers, consisting of 363 species in 112 genera. They occur as far north as Alaska and as far south as Tierra del Fuego, though the highest concentration can be found in Central and South America.
Hummingbirds closest living relatives are swifts and treeswifts, which they split from about 42 million years ago. They share a very similar body shape and habit of spending much of their time in the air.
While looking and acting very similar to the Old World Sunbirds,a class of birds found in Africa, and Australia, these groups are not related at all. These similarities are due to convergent evolution to fill in the same niche.
Overall, hummingbirds have small compact bodies with long thin wings. They have very short legs with three toes forward and one backwards. Because of these short legs, they can perch, but not really walk. Which fits their lifestyle of mainly flying from flower to flower. Their plumage comes in a wide variety of colors, including greens, blues, pinks and purples.
Their size ranges from the smallest, the bee hummingbird at up to 2 inches, weighing only .07 oz (2g) to the giant hummingbird at 9.1 inches and weighing 18–24 grams.
This family has many unique specialized adaptations. Even their flight is unique, not only can they fly forward, but they can even hover and go backwards. Their wing flapping rates can vary from 12 times a second all the way up to 80 per second in smaller species.
The humming sound created from their unique flight has given rise to their name. In some species, their tail feathers can even produce sounds during courtship displays.
While hummingbirds may use the humming sound created from their flight style to commute with others, they also use vocal communications. This usually involves a variety of buzzes, chirps, squeaks and whistles. These communications can be used in a variety of ways including territoriality and courtship.
It might even be the case, as seen in the blue-throated hummingbirds, that some species might have a singing pattern containing ultrasonic clicks that disrupt insects in flight, allowing for easier capture.
Of the 363 species of hummingbird found worldwide, only 15 species can be found regularly in North America, being seen in every state except Hawaii, up to 25 different species have been documented in North America. On the other hand, Columbia can boast an incredible 160 species and Ecuador up to 130 unique species. Though, if you like me and live east of the Rockies, you’re for the most part going to have to be happy with just the Ruby-throated Hummingbird because for the most part, that’s all you’re really going to see.
Since most Hummingbird species live in the tropics, most do not migrate, though some in North America do. The rufous hummingbird is one of them, having one of the longest migration routes based on body size. This little bird, just about three inches long, migrates about 3,900 miles from Alaska to Mexico twice a year, which ends up equaling about 78,470,000 body lengths.
It seems to be well known that hummimgbirds have a fondness for the colors red, orange and even pink, you’ll see this reflected in most of the commercial hummingbird feeders on the market. While this may be true, they will feed from flowers of many different colors. Interestingly, while most birds see in a wide range of the color-spectrum including uv, hummingbirds see only to near-ultraviolet.
This is because there tends to be a difference between insect pollinated flowers and hummingbird pollinated flowers. While insect-pollinated flowers produce colors into the uv-spectrum, ones that are primarily hummingbird-pollinated do not. This smaller color array may make hummingbird flowers less appealing or noticeable looking to insects, probably in an attempt to prevent insects from collecting their nectar. Another interesting thing to note is that hummingbird-pollinated flowers also tend to have weaker nectar with a higher proportion of sucrose, whereas insect-pollinated flowers’ nectar is strong with higher fructose and glucose.
Not surprisingly, hummingbirds have large eyes compared to the size of their heads. They rely on them to find nectar sources in a sea of foliage and green. On top of that, they have large corneas and cells that are used for visual processing and light perception.
They have also evolved increased retinal neurons to be able to process and navigate in their environment, something very important with their rapid and acrobatic flight style. A cool bit of information is that that studies have shown that hummingbirds have some of the largest neuronal hypertrophy in any bird, meaning that they have some of the highest capability of visual processing, most likely due to their increased need of additional processing from their rapid flight, courtship, foraging style and collision avoidance.
Hummingbirds, being nectarivores, also have an interesting connection with ornithophilous flowers. There is much display of coevolution between the two groups including things such as bill shape, length, curvature and even body size. This is extremely interesting when looking at hummingbird species such as the sword-billed hummingbird and sickle bills, which coevolved with a very small number of flower species which they feed from. Looking at the bee hummingbird, it may have even evolved its miniature size due to having to compete with larger and longer billed hummingbirds, making it easier to be small and just needing to compete against insects for flower sources.
While generally birds don’t have a good sense of taste, hummingbirds have evolved receptors allowing them to taste sweetness and carbohydrates.
While they primarily consume nectar and get their required energy from them, they are lacking in several needed nutrients. To get these missing nutrients, insects are included in their diet. Some of their preferred prey include a variety of flies, gnats, mosquitos and spiders.
Since they have such high metabolism, it can be dangerous in times where they can’t get the needed energy to supply their high energy expenditure. To get around this, and survive these lean times, they can go into a near hibernation state called torpor. When they enter torpor, their metabolic rate can sometimes drop to 1/15 of what it normally is. This can help them conserve energy during periods of cold weather or even at night. During this time, they will go into a deep-sleep, their body temperature can drop drastically, along with heart and breath rate. One hummingbird species has even had its temperature recorded to go as low as 38F in torpor, the lowest temperature of any bird or non-hibernating mammal.
All species are sexually dimorphism, with the males having distinct coloring, most specifically an ornamental gorget- an iridescent throat patch that often appears as different colors depending on the viewing angle due to the nano structures of those feathers. Depending on the species, the larger of the sex can vary. In smaller species, males tend to be the smaller ones, in larger species, the females tend to be larger. In others, both males and females can be similar sized. Though size isn’t the only difference that is demonstrated between males and females, bill size and shape can even vary. In some species groups, females can have longer and more curved bills. This difference likely evolved due to constraints from the males complex displays and possibly larger size, larger curved bills may impede these displays. Their smaller size may also allow them to conserve more energy, allowing them to spend more time in courtship.
After courtship, females will build a cup shaped nest, sometimes as small as a half a walnut shell, out of various materials. Typically, two small white eggs are laid, with around a 14-23 day incubation period following. After hatching, they will remain in the nest for an additional 18-22 days before fledging.
Overall, unfortunately most species in this family are in decline. Of the 363 hummingbird species, 9 are classified as critically endangered, 17 endangered, 10 vulnerable, and 19 species are near-threatened.
Some of the main threats include pesticides, window collisions, outdoor cats, habitat loss and climate change affecting food availability.
Though it is not all doom and gloom, the Anna’s hummingbird has been having a population growth and is even expanding its range northward and residing year-round in some colder climates.
Many of these threats faced by hummimgbirds are easily preventable. There are many ways we can help protect our local hummingbirds. Window clings, and various other methods can help birds see through the reflective surface of many windows and can prevent many avian deaths. Pesticides applied for so called ‘weeds’ and insects, both can have deadly effects on these flying jewels, avoiding the use of these to protect not only birds, but any living thing that will use the water source that these chemicals will eventually leach into. Fun ways of helping local hummingbirds and other local pollinators is making sure to landscape with native plants and creating a bird friendly yard.
Some cool parting hummingbirds facts are that a hummingbird’s heart can beat up to 1,260 beats a minute and they can take up to 250 breaths in a minute.