The hummingbird is the Family Trochilidae consisting of 325 to 340 species in at least 102 genera, depending on how the classification system is interpreted. It is truly an American bird as it is found only in the western Hemisphere from Alaska to Tierra del Fuego, depending upon the season. The largest number of species, about 160, is found in Ecuador.

About 21 species are seen in the US, the exact number sighted varies from year to year, but only a few are year-round residents along the southwestern border. Most species are migratory. The Rufous hummingbird may fly up to 3000 miles from winter homes in Central America to summer nesting areas as far north as Alaska. Even more amazing is the fact that hummingbirds do not migrate in flocks but travel alone. The young leave the nesting area last and fly to the winter home with no adult to guide them.

At least one kind of hummingbird spends the summer in just about every part of the continental US. Anna’s are the only hummingbirds to typically spend winters in the US and Canada.

Metabolism

A hummer’s metabolism is astonishing. A hovering 3 to 4 gram bird uses about 35 calories per minute, breathing up to 250 times per minute. A hummer’s heart is proportionately the largest in the animal kingdom and has a resting rate of 480 beats per minute and can reach up to 1260 beats per minute when excited.

The normal body temperature of the hummer is 103 degrees F but can be lowered below 60 degrees F in a state known as torpor. Torpor is not sleep but is a powered-down state used to control and conserve energy. People sometimes witness the torpor state as death and are astonished when the “dead” bird gets up, shakes itself, and flies away.

In order to maintain this exceedingly high metabolism the hummer must feed at least every 15 to 20 minutes all day, eating twice their weight every day. Dawn and dusk see a higher feeding rate as the bird must quickly recover from a night of not feeding or get ready for the nightly fast. If unable to feed because of bad weather, a hummer may induce torpor and conserve energy until feeding can be done. In relation to relative body weight, hummingbirds require about 75 times as many calories per day as humans.

Hummer Food

Hummingbirds have an utterly astonishing metabolism to support their frantic lifestyle. This energy comes generally from flower nectar and the sugar water in the feeders of hummingbird lovers. Protein is the primary food and comes from hunting small soft-bodied insects and spiders on visited foliage or on the fly by a behavior called “hawking”. You can assist your hummers in the protein hunt by providing a small bowl of overripe fruit (banana peels are excellent) to draw the types of small insects hummers love.

Note that for several weeks in mid-summer the hummers’ use of nectar dwindles as they are concentrating on protein for the babies. During this time many people see fewer hummers and assume they are gone or that the feeder is not working. Don’t lose hope or pull the feeders or let the nectar go bad in frustration; they will be back with the fledglings when they are ready.

Coloring and Feathers

The hummer’s striking iridescent coloring has given them the nickname “Nature’s Jewels”. The color comes from two sources. The first is the pigment color of the feather and the second is a property known as structural color.

Interestingly, the pigment colors in hummer feathers do not include red or yellow. The feather pigment colors are limited to black, brown, and reddish brown. Structural color refers to the color reflected from the facets of the feathers and accounts for the shifting iridescence of the plumage. Hummer feathers may appear to be different colors when viewed from different angles.

White hummers, albino, are not unknown and are not a separate species. In the eastern US, an albino bird is most likely to be a Ruby-throated.

Sounds

The name hummingbird comes from the distinctive hum caused by the rapid wing beat in flight. Various species have distinctive hums as a result of beat rate and wing feather shape. Hummingbirds also have vocal chirps, chatters and buzzes to signal others, indicate mood, and to threaten. Most do not have a song as such though the Anna’s hummingbird has been known to voice long “songs”.

Flight

In a world in which birds fly only forward, the hummingbird defies all logic and does it forward or backward, side to side, motionless in a hover, or even upside-down. This unique skill is because hummers get power on both the up- and down-stroke while other birds power on the down-stroke only and flap their wings at a much slower rate. In fact, in a hover, the hummer sweeps its wings in a flat figure-8 of about 50 strokes per second. This speed is above the human ability to focus and accounts for both the blur we see and the distinctive hum we hear. While performing his special courtship dance, a male hummer’s wings may beat up to 200 times per second! Hummers have unusually large flight muscles, which make up about 25 percent of their total weight.

Lifespan

Hummingbirds may live 5 to 10 years in the wild but it is not an easy life. Fledgling mortality has been observed from 17% to 59%, many lost to predation by hawks, crows, other large birds, and snakes. Accidents, high winds, cold, heat, or flood also take many young and adult birds every year. High winds are apparently a major factor in the migration of the Ruby-throated hummingbird across the Gulf of Mexico from the Southern US to Yucatan in Mexico.

Banding

The process of capturing and banding hummingbirds is used to study these largely unstudied birds. Capturing and banding may be done ONLY by researchers certified and licensed by the US Fish and Wildlife Service. There are currently about 80 authorized banders in the US and their work has significantly increased hummingbird data.

Hummingbirds are usually captured using a feeder placed in a drop-door cage or by the use of fine “mist” net corrals. Mist nets are illegal to possess except by licensed banders. After capture the birds are placed in special “holding blankets” usually made from the toe of a silk stocking. Each bird is banded with a tiny numbered band and its age, weight, bill length, tail length, and wing length are recorded. When all the data has been noted, the bird is offered a snack and then released.

By: Terrie Merritt

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