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RUBY-THROATED HUMMINGBIRD

RUBY-THROATED HUMMINGBIRD

RUBY-THROATED HUMMINGBIRD

Family Trochilidae

Hummingbirds are most closely related to trogons and swifts. Some taxonomists have classified hummingbirds as a separate order (Trochiliformes) and some feel that it is the hummingbirds, rather than woodpeckers, which compose the sister group to passerine birds. Hummingbirds are only found in North and South America; they do not exist in the Old World. Their inability to fly long distances (such as over an ocean) may be one of the main factors limiting their spread. Some are extremely specialized with regard to their habitat. For example, some South American species are only found at altitudes of 12,000 to 15,000 feet and one is only found on Mount Chimborazo in Ecuador. Thirteen species of hummingbird breed in the continental United States ( of which several are found only in the region near the border with Mexico) and four species breed in Canada. Only one species can be found east of the Mississippi River (Greenewalt, 1960).

The largest hummingbird lives in the Andes and measures 8 inches (Patagona gigas). The smallest species Calypte helenae can weigh 2 grams while Patagona gigas can weigh 20 grams; half of this length is composed of the bill and tail. Hummingbirds have the highest metabolisms of animals in the world. A hummingbird which is hovering has about 10 times the energy output (adjusted for body size) as a human running 9 miles an hour. Relative to their body weight, hummingbirds have about 45 times the caloric expenditure per day as humans (Greenewalt, 1960). Hummingbirds have the highest pulse among animals (reaching 1260 pulse beats/minute) and the highest respiratory rate (reaching 273 respirations per minute) (Skutch, 1973). Hummingbirds feed primarily on nectar (about half their weight in sugar per day) but also include insects in their diet. Most hummingbirds are unable to walk or hop on the ground (Skutch, 1973).

Some hummingbirds can withstand cold temperatures such as those which inhabit mountain forests 15,000 feet high in South America (Skutch, 1973).

The ruby-throated hummingbirds can reach maximum speeds of 27 mph while others can reach 47 mph (Skutch, 1973). Rubythroated hummingbirds can fly more than 500 miles across the Gulf of Mexico in one nonstop flight which lasts about 26 hours. The rufous hummingbird weighs 3-4 grams and can migrate distances of two thousand miles (Skutch, 1973).

Hummingbirds are flying at almost full speed from the moment they take off. Their large flight muscles attach to a sternum and its keel which are larger than normal for their size (Skutch, 1973).

     Calliphlox amethystine can beat its wings 80 times per second and weighs about 2.8 grams.  Larger hummingbirds weighing between 5 and 7 grams typically beat their wings 20 to 25 times per second.  Female ruby throated hummingbirds beat their wings 50 times per second and males beat their wings 70 times per second.  While they can make sounds, especially males, virtually no hummingbirds produce musical songs (although there are a few exceptions such as Schistes geoffroyi) (Greenewalt, 1960). The largest hummingbirds beat their wings 8 to 10 times per second while those which weigh 5-7 grams beat their wings 20-25 times/second. Ruby-throated and rufous hummingbirds can beat their wings 200 times per second during courtship (Skutch, 1973).

Individuals of several species of hummingbird have lived 9-10 years.

While the bill of the sword hummingbird stretches 4 inches, as long as its body and tail, that of the purple-backed thornbill measures only 5/16 inch which is shorter than the rest of its head. While the bills of most hummingbirds are straight, many curve downwards, and one species even curves upwards (Skutch, 1973).

Hummingbirds bathe frequently (Skutch, 1973).

Although iridescent green is the most common color in hummingbird plumage, various species can add a variety of other colors as well. Some hummingbirds are rather drab in their coloration.

Males and females usually only associate with each other long enough to mate. A group of males may gather together in a lek to sing and females may approach the lek to mate with the male of her choice. Courtship in many species involve dramatic male flight patterns and some males sing while they fly (Skutch, 1973). Hummingbirds do not mate for life and males even attempt to mate with other species (and a number of hybrids between species have been produced). Hummingbird females usually lay 2 eggs which are incubated for about 2 weeks. The amount of food the mother is able to bring the nestlings determines how much time they spend at the nest. In ruby-throated hummingbirds, the nestling time can vary from 10 to 30 days (Greenewalt, 1960). Females build the nest and some species are colonial with multiple females nesting in the same area. In some species, multiple females may lay eggs in the same nest. In many species, two clutches of eggs can be laid per year and nests may be reused. Typically, two white eggs are laid which vary in size from the 12x8 mm eggs of the calliope hummingbird to the 20x12 mm eggs of the giant hummingbird (Skutch, 1973).

Although hummingbirds have a smaller number of feathers than other birds (940 for a ruby throated hummingbird), they seem to have a higher density of feathers than any other group of birds. The flight muscles of hummingbirds comprise 25-30% the total body weight which is higher than in any other group of birds. Hummingbird top speeds reach 26 miles an hour. Ruby throated hummingbirds feed on nectar (especially from red flowers) and obtain protein by feeding on insects. They may also feed on sap from the sap holes made by sapsuckers. Hummingbirds have long tongues which wrap around the inside of their head when not extended (Greenewalt, 1960).

Hummingbirds are preyed upon by hawks and other birds (even Baltimore orioles), frogs, praying mantises, and dragonflies. Some get caught in thick spider webs. Nests are preyed upon by snakes, ants, bats, and other birds (Skutch, 1973).

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RUBY-THROATED HUMMINGBIRD RUBY-THROATED HUMMINGBIRD
RUBY-THROATED HUMMINGBIRD RUBY-THROATED HUMMINGBIRD
RUBY-THROATED HUMMINGBIRD RUBY-THROATED HUMMINGBIRD
RUBY-THROATED HUMMINGBIRD RUBY-THROATED HUMMINGBIRD
RUBY-THROATED HUMMINGBIRD