The Biogeography of Mellisuga helenae:

 Cuban Bee Hummingbird
Anne Battle
November 23, 2004
Geography 115

 Native and endemic to the island of Cuba, this tiny bird is ignites curiosity in  both  researchers and bird watchers the world over. The brilliant iridescence of their feathers and their eccentric behavior illicit much desire to not only study these creatures, but to simply get up close and personal with these jewels of the natural world. Hummingbirds offer many extremes in the animal kingdom seeming to push the envelope of what such a small creature can do!

Phylum            Chordata

Class               Aves

Order               Trochiliformes

Family              Trachilidae

Genus              Mellisuga

Species           helenae

           The bee hummingbird belongs to an extensive family called Trachilidae, which comes from the word meaning a bird. Within this family includes one hundred and twenty three genera and three hundred and thirty eight species. The hummingbird origins are in the western hemisphere. However they now occur on six of the seven continents with the exception of Antarctica. “They have successfully adapted to every kind of climate: cold, heat, dryness and humidity; indeed they can even tolerate snow and short frosts” (Scheithauer 1966). Essentially hummers, as they’re called, are tropical and subtropical birds. Their territory ranges from Tierra del Fuego up to Alaska, and with the greatest number of species, 163, found in the equatorial belt- the region ten degrees north and south of the equator. The more north and south  from the equator one goes  the less number of species of hummingbirds occur.

             Measuring a mere 2.25 inches in length and weighing only 0.07 ounces, or two grams, less than the weight of two paper clips, the Cuban bee hummingbird  is indeed the smallest bird in the world.(Figure ) Furthermore, the bee hummingbird is also the smallest warm-blooded vertebrate. Humming birds in general are highly specialized, and set themselves apart from all other groups of birds. They have the fastest wing beat out of all birds, in forward flight 80 beats per second and up to 200 beats per second while mating. They are one of fastest of all small flying birds. Their heart rate is the second fastest of all animals. Some shrews are faster, with 1260 beats per minute. With thirty percent of their body weight coming from breast muscles, they have relatively the largest breast muscles of all birds. When compared to the size of their body they have the largest heart of all warm-blooded animals. The weight of their brains gives them relatively the largest brain of all birds, weighing 4.2 percent of total body weight. Due to their extremely small bodies hummers are some of the most densely feathered birds, but with only 1000 or less feathers they have fewest feathers of all birds. “They are the only birds that become torpid at night, with a drop in body temperature of as much as 66 F. Their normal body temperature is among the highest (104 F) of all birds” (Johnsgard 1983).  It is not uncommon for these birds to eat half their total body weight and drink eight times their weight in water a day. Figure 1

    With all the specialties that hummingbirds have evolved, their body structure is just as specialized. The bee hummingbird has a wing span, on average, of thirty millimeters. Their wings lack a wrist and forearm joint that are most species of birds have, so hummer’s wings act like “oars” with a fluid and constant motion. The skeleton offers unique specializations, including an enlarged sternum, and eight pairs of ribs unlike the typical six pairs. This structure helps to protect them against the unique stresses of their specialized flight. Like all hummingbirds the bee hummingbird feeds on nectar as an adult, thus their bill surrounds a tongue that is basically as long as the bill itself. However, the tongue can be stretched greatly beyond the end of the bill; this tongue is helpful in reaching deep into tubular flowers.  The male has a fire-red crown and throat. The gorget, an iridescent patch of color on the throat, has elongated lateral plumes. (Figure 1 )

Figure 1

The bright gorget can be red as above or blue or violet.

           The male bee hummer on top is mostly blue while underneath he is mostly grayish white. (Figure 2) Females are green on the above portion and white underneath. She has white tail feathers. The outer feathers on both genders can be iridescent, which help to create even more of blur, when combined with the high speed flight, thus becoming a hard target for predators. Figure 2

A male Cuban bee hummer having one of many meals he will have throughout his day, notice the blue/ green coloring.

            A hummingbird puts out relatively one of the highest amounts of energy in all the animal kingdom. These tiny birds will visit anywhere from one thousand to two thousand flowers in a day; not only feeding themselves, but filling a niche as pollinator for flowers. (Figure 3) If we convert hummingbird’s diet into our caloric terms to compare our two diets, the miniature creatures would ingest an average of 155,000 calories per day! Along with high fructose and glucose nectar, hummers eat great numbers of small flies and spiders, which provide the birds with protein, fats, minerals, and vitamins.

Figure 3

A female ruby- throated drinking nectar.

            In order to attract a mate the male hummingbird performs an elaborate flying spectacle. He will beat his wings incredibly fast while hovering right in front of his prospect as she perches, making sure his bright iridescent chest can be seen. He then shoots up to sixty feet in the air and free falls back down before he halts his dive in mid flight directly in front of her. He’ll repeat the up and down air show until she accepts him. If a competing male gets in the way of male number one, number one will attack it with fervor, even if the intruder is larger.  Males are in no way monogamous, they will mate with as many females as he can.

            Due to their small body size this hummer does not have the ability to fly across the water that separates the island of Cuba from other lands further away. Thus, the Cuban bee hummingbird is found in Cuba as well as on the Isle of Pines. Its habitat is woodland and suburban gardens. Hummingbirds appear to not feel threatened by humans as most people throughout the western hemisphere see hummers regularly. These beautiful and fascinating birdies are definitely sexy. With names like amethyst, ruby and topaz, blue-chinned sapphire, puff-leg, racket-billed, giant or bee hummingbird the species appeals to our love of extravagance, color, extreme characteristics.   

             The Bee Hummingbird, Mellisuga helenae, as fascinating and specialized as it is, is far too narrow a subject to find adequate data about its biogeographic history. Fortunately when one researches the biogeographic history of hummingbirds as a whole there is plenty of information accessible.       

             Hummingbirds are in the class Aves. This class is of birds. “Birds are vertebrates with feathers, modified for flight and active metabolism” (Animal Diversity). Within this class lies the order in which hummingbirds are classified in: Apodiformes. This order also consists of swifts.  There are three distinct families within the order. Family Apodidae are swifts; Family Hemiprocnidae are crested swifts; and Family Trochilidae are hummingbirds (Animal Diversity).

The family of hummingbirds is divided into two sub-families. One family, Trochilinae, has all of the colorful species. Nearly 300 make up this subfamily. Phaethornithinae, the other subfamily, “consists of six genera and 34 species of birds called hermits” (Monterey Bay). Hermits can be just as small or big as a variety of their relatives the hummer. Most hummingbirds are nectarivorous and insectavorous, meaning they make food out of plants’ nectar and insects. However, hermits are exclusively insectivores. Where most hummingbirds are bright and colorful with iridescence, hermits are mostly colored with neutral colors of brown, gray, white and black.   “Only few species have iridescence” (Monterey Bay). “Unlike many other hummingbirds, hermits are not generally territorial” (Monterey Bay).

Scientists have a real hard time composing the evolutional history of hummingbirds because fossil remains are tremendously rare. The fact that they have such a small skeletal structure and such small bones are the main reason fossils of hummers are hard to find. The bones just don’t have the structural integrity to hold up over time- they simple disintegrate before they have a chance to fossilize. Modern birds are thought to have appeared during the Cretaceous era, over 65 million years ago. Furthermore the order of modern birds most likely derived from the same ancestor. (Bird Biogeography) Throughout the Paleocene (37-65 million years ago) scientists agree there was a great radiation event. It is most likely that during this time hummingbird’s ancestors settled in the “New World”. The continents of North America and South America are the only places hummingbirds naturally call home. Scientists agree it is simply physically impossible for hummingbirds to cross the Atlantic Ocean when left to its own devices.

            South America is thought to be the hummingbird’s place of origin. (Johnsgard 1983) The continent has the highest concentration of hummers, as well as the hermit group that eats only insects is restricted to this region (Johnsgard 1983). The oldest fossils on record, until recently, were 1 million year old specimens. They were found in Central America.  There is some evidence now that hummingbirds may have once lived in the “Old World”. Excavations in southwestern Germany unearthed the first hummingbird fossils in the “Old World”. These were dated 34-30 million years ago.

            Scientists now have to answer the question of if hummers were once on the continents of Europe, Asia, and Africa why did they go extinct? According to Science News “these continents have no geographic barriers that would have prevented the birds from spreading far and wide.” Since their range in the Western Hemisphere is so wide, why would they go extinct in these other regions?

            Part of the wonder of hummingbirds is their awesome evolution and excellent adaptations. They are so tiny and they fly so fast and for some reason they can reverse their forward motion and fly backwards. They can even hover like a helicopter! (Figure 4) These characteristics make them elusive targets for scientist to catch and study. The attributes that keep them so fascinating to us also keep us in the dark about so much of these bird wonders. They truly offer a natural mystery that humans have been trying to solve for decades, and no doubt will keep searching for answers to this sleuth.  Figure 4

While this female hovers in front of the feeder her wings beat so fast they are nearly invisible!

            As a little kid I can remember the thrill of waking up in the morning, glancing out the window through the corner of my eye and getting that split second flutter as a hummingbird jets up to glass and then zooms away just as fast. Even as an adult I still feel a rush of excitement upon witnessing these aeronautical acrobats. In the western hemisphere hummingbirds occur naturally unlike any where else in the world. Furthermore mankind, being the curious and self-serving species that we are, finds it pleasurable to keep these little lovelies close by. The environmentalist adage, “Not In My Back Yard” (NIMBY for short) surely does not apply to hummingbirds. Most people are nothing short of happy to host hummingbirds in their front and backyards. People spend enormous amounts of money and energy in creating everything from elaborate flower gardens that attract hummers by the hundreds down to hanging a simple hummingbird feeder filled with artificial nectar right outside a kitchen window. Even though hummingbirds have a cosmopolitan distribution pattern throughout the world, the place in which they are thought to have originated is severely endangered.

 The tropical rainforest of South America is home to the greatest number of hummingbirds on the planet. Sadly this essential ecosystem is continually being destroyed at ever alarming rates.

“Try snapping your fingers once every second. In the time it takes for the noise of one snap to disperse, an acre of rainforest will have disappeared forever. Central Park in New York would take about sixteen minutes” (Mitchell 1990).

“Thirty percent of the world’s rainforests are in the Brazilian Amazon” (Mitchell 1990). With this destruction due to deforestation comes the loss of hummers in their native habitat. Deforestation is an intentional and deliberate action by people who do away with the forest in order to use the land for cattle grazing, housing, and other real estate endeavors. Lucky for hummers they have extraordinary adaptability and have thrived everywhere they have been introduced by man.

            Man has taken the hummingbird all over Europe, Africa, Asia and Australia. Explorers would bring them back as gifts to the sponsoring royalty. They were revered for their unique talents as well as their jewel-like appearance. An unfortunate fate of thousands of birds, including hummingbirds, took place during the 19^th century. At this time people in Europe required the elaborate feathers of tropical birds to embellish women’s elegant hats. “Thus began one of the most gigantic commercial exploitation of birds” (Dorst 1967). Because they are such good dispersers after being introduced to a new area they would flourish.  We find them in state and city parks, we find them in coastal areas as well as inland areas, and “we find them as far north as Alaska and as far south as Tierra del Fuego” (Dorst 1967). Hummingbirds live in tropical rainforests the world over.

Another aspect that adds to hummers’ luck is that if global warming increases so does the hummers habitat. As increase levels of carbon dioxide enters the atmosphere the earth’s climate gets warmer which could give more opportunities for tropical rainforest biome to occur (MacDonald 2003). This increase affects the rate of photosynthesis in plants and plant growth (MacDonald 2003). “Recent studies indicate that large areas of arctic tundra will be replaced by boreal forest and, in turn, areas that presently occupied by boreal forest will be replaced by temperate deciduous forest and grassland” (MacDonald 2003). So on and so forth all of the biomes will shift down latitude because the climate is not cold enough for as many cold climate regions to exist. “Rainforests will expand in South America, Africa and Asia” (MacDonald 2003).   

Hummingbirds are not on any endangered species list, nor is man trying to eradicate them from existence. As has been said, the relationship between man and hummingbird is quite the contrary. Where other organisms are going extinct because they might be a hindrance to man’s progress, for example, living on land that people want to develop or being a pest in agriculture, the hummingbird is greatly appreciated by man. We go to much length to be able to keep them as our neighbors. (Figure 5) The evidence is clear: in any bookstore or library there are armfuls of books, not to mention magazine articles, that teach people how to construct gardens that will attract hummers; malls across America will host live hummingbird exhibits that travel through for weeks at a time; finally zoos and animal parks all over the world create habitats that overwhelm the public with high concentrations of the beautiful birdies. It’s safe to say that people get along with hummers, and in this day and age it is a good thing for them that they are so charismatic, for this is one reason why they have been spread around the world.

Researchers will use several feeders in one area to collect data on hummers eating habits.

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            Overlook Press, 1990.

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            http://web7.infotrac.galegroup.com/itw/infomark/211/48/53023872w7.

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            Classification. October 25, 2004.

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