(Click images to enlarge and to view individual bird ID. - all images captured by Raymond J Barlow)
Hummingbirds are birds that comprise the family Trochilidae. They are found from southern Alaska, all the way down to Tierra del Fuego, the tip of South America. They are among the smallest of birds, most species measuring in the 7–13 cm (3–5 in) range. The smallest living hummingbird is the 5-cm Bee Hummingbird. They can hover in mid-air by rapidly flapping their wings 12–80 times per second (depending on the species; the larger birds tend to flap less). They are known as hummingbirds because of the humming sound created by their beating wings, which sometimes sound like bees or other insects. To conserve energy while they sleep or when food is scarce, they have the ability to go into a hibernation-like state (torpor) where their metabolic rate is slowed to 1/15th of its normal rate. They are also the only group of birds with the ability to fly backwards. They can fly at speeds exceeding 15 m/s (54 km/h; 34 mph). Individuals from some species of hummingbirds weigh less than a penny.
Hummingbirds drink nectar, a sweet liquid inside certain flowers. Like bees, they are able to assess the amount of sugar in the nectar they eat; they reject flower types that produce nectar that is less than 10% sugar and prefer those whose sugar content is stronger. Nectar is a poor source of nutrients, so hummingbirds meet their needs for protein, amino acids, vitamins, minerals, etc. by preying on insects and spiders.
Hummingbirds are specialized nectarivores and are tied to the flowers they feed upon. Some species, especially those with unusual bill shapes such as the Sword-billed Hummingbird, are co-evolved with a small number of flower species.
With the exception of insects, hummingbirds while in flight have the highest metabolism of all animals, a necessity in order to support the rapid beating of their wings. Their heart rate can reach as high as 1,260 beats per minute. They also consume more than their own weight in nectar each day, and to do so they must visit hundreds of flowers daily. Hummingbirds are continuously hours away from starving to death, and are able to store just enough energy to survive overnight.
Hummingbirds have long lifespans for organisms with such rapid metabolisms. Though many die during their first year of life, especially in the vulnerable period between hatching and leaving the nest (fledging), those that survive may live a decade or more. Among the better-known North American species, the average lifespan is 3 to 5 years. By comparison, the smaller shrews, among the smallest of all mammals, seldom live more than 2 years.
(Also view the Anna’s Hummingbird, the Ruby-throated Hummingbird, the Rufous Hummingbird, the Giant Hummingbird, the Broad-tailed Hummingbird, the Violetear, and the Mountaingem.)