WOW-there are hummingbirds everywhere over here at my place! Quite a few people have come to photograph the birds and can't believe what they are seeing. Hundreds of tiny birds swarming the feeders is not seen in the wild around flowers. Humans have conditioned the hummers to the artificial glass and plastic nectar feeders! My Mom was a first generation feeder hanger. Every year she would hang more feeders as more birds came to be sure everybody had enough. I got my first feeder as a wedding present back in 1970. The birds have adapted to using the feeders to quickly add weight for the long journey to Mexico over the Gulf of Mexico. They know where the feeders are hung and return every year to the same places. Thankfully, many new people are getting into the joy of birds and helping the hummers. I have shared below some excerpts of interesting facts about hummingbirds from Wikipedia. Enjoy!
Highlights from August 17 and 18-2014
You are welcome to visit my Albums for complete photoshoot, just click on links:
From Wikipedia, the free encyclopedia
Hummingbirds are New World birds that constitute the family Trochilidae. They are among the smallest of birds, most species measuring in the 7.5–13 cm (3–5 in) range. Indeed, the smallest extant bird species is a hummingbird, the 5-cm bee hummingbird, weighing less than a U.S. zinc penny (about 2.5g).
They are known as hummingbirds because of the humming sound created by their beating wings which flap at high frequencies audible to humans. They hover in mid-air at rapid wing flapping rates, typically around 50 times per second, but possibly as high as 200 times per second, allowing them also to fly at speeds exceeding 15 m/s (54 km/h; 34 mph), backwards or upside down.
Hummingbirds have the highest metabolism of any homeothermic animal. To conserve energy 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.
|Female black-chinned hummingbird|
Specialized characteristics and metabolism
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 during hovering and fast forward flight. Their heart rate can reach as high as 1,260 beats per minute, a rate once measured in a blue-throated hummingbird, with a breathing rate of 250 breaths per minute, even at rest. During flight, oxygen consumption per gram of muscle tissue in a hummingbird is approximately 10 times higher than that seen for elite human athletes.
Hummingbirds 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 are rare among vertebrates in their ability to rapidly make use of ingested sugars to fuel energetically expensive hovering flight, powering up to 100% of their metabolic needs with the sugars they drink (in comparison, human athletes max out at around 30%). One study showed that hummingbirds can use newly ingested sugars to fuel hovering flight within 30–45 minutes of consumption. These data suggest that hummingbirds are able to oxidize sugar in flight muscles at rates high enough to satisfy their extreme metabolic demands. By relying on newly ingested sugars to fuel flight, hummingbirds can reserve their limited fat stores to sustain them overnight fasting or to power migratory flights.
The dynamic range of metabolic rates in hummingbirds requires a corresponding dynamic range in kidney function. The glomerulus is a cluster of capillaries in the nephrons of the kidney that removes certain substances from the blood, like a filtration mechanism. The rate at which blood is processed is called the glomerular filtration rate (GFR). Most often these fluids are reabsorbed by the kidneys. GFR also slows when a bird is undergoing water deprivation. The interruption of GFR is a survival and physiological mechanism unique to hummingbirds.
Studies of hummingbirds' metabolisms are relevant to the question of how a migrating ruby-throated hummingbird can cross 800 km (500 mi) of the Gulf of Mexico on a nonstop flight. This hummingbird, like other birds preparing to migrate, stores fat as a fuel reserve, thereby augmenting its weight by as much as 100% and hence increasing potential flying time over open water.
Hummingbirds are capable of slowing their metabolism at night or any time food is not readily available, entering a hibernation-like, deep sleep state known as torpor needed to prevent energy reserves from falling to a critical level. During nighttime torpor, body temperature falls from 40oC to 18oC, with heart and breathing rates both slowed dramatically (heart rate to roughly 50 to 180 beats per minute from its daytime rate of higher than 1000).
During torpor, to prevent dehydration, the kidney glomerular filtration rate ceases, preserving needed compounds like glucose as a source of fuel, water and nutrients. Further, body mass declines throughout nocturnal torpor at a rate of 0.04 g per hour, amounting to about 10% of weight loss each night. The circulating hormone, corticosterone, is one signal that arouses a hummingbird from torpor.
Use and duration of torpor vary among hummingbird species and are affected by whether a dominant bird defends territory, with non-territorial subordinate birds having longer periods of torpor.
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 probably 3 to 5 years. By comparison, the smallershrews, among the smallest of all mammals, seldom live more than 2 years. The longest recorded lifespan in the wild is that of a female broad-tailed hummingbird that was banded (ringed) as an adult at least one year old, then recaptured 11 years later, making her at least 12 years old. Other longevity records for banded hummingbirds include an estimated minimum age of 10 years 1 month for a female black-chinned similar in size to the broad-tailed, and at least 11 years 2 months for a much larger buff-bellied hummingbird.
Aerodynamics of flight
Hummingbird flight has been studied intensively from an aerodynamic perspective using wind tunnels and high-speed video cameras.
Two studies of rufous or Anna's hummingbirds in a wind tunnel used particle image velocimetry techniques to investigate the lift generated on the bird's upstroke and downstroke. The authors concluded that the birds produced 75% of their weight support during the downstroke and 25% during the upstroke. Many earlier studies had assumed that lift was generated equally during the two phases of the wingbeat cycle, as is the case of insects of a similar size. This finding shows that hummingbird hovering is similar to, but distinct from, that of hovering insects such as the hawk moths. Further studies using electromyography in hovering rufous hummingbirds showed that muscle strain in the pectoralis major (principal downstroke muscle) was the lowest yet recorded in a flying bird, and the primary upstroke muscle (supracoracoideus) is proportionately larger than in other bird species. Hummingbird hovering has been estimated to be 20% more efficient than performed by ahelicopter drone.
The giant hummingbird's wings beat is as low as 12 beats per second and the wings of typical hummingbirds beat up to 80 times per second.
A slow motion video has shown how the hummingbirds deal with rain when they are flying. To remove the water from their heads, they shake their heads and body, similar to a dog shaking to shed water. Further, when raindrops collectively may weigh as much as 38% of the bird's body weight, hummingbirds shift their bodies and tails horizontally, beat their wings faster, and reduce their wings' angle of motion when flying in heavy rain.
The outer tail-feathers of male Anna's hummingbird (Calypte anna) vibrate during courtship display dives and produce a loud chirp. When courting, the male ascends some 30 meters before diving over an interested female at a speed of 27 m/s, equal to 385 body lengths/second, producing a high-pitched sound. This downward acceleration during a dive is the highest reported body length displacement for any vertebrate undergoing a voluntary aerial maneuver; by comparison, it is about twice the diving speed of peregrine falcons in pursuit of prey. At maximum descent speed, approximately 10 g of gravitational force occurs in the courting hummingbird during a dive. By comparison to humans, this is a g-force acceleration causing near loss of consciousness in fighter pilots during flight of fixed-wing aircraft in a high-speed banked turn.
Experiments showed that hummingbirds could not make the courtship dive sound when missing their outer tail-feathers, and that those same feathers could produce the dive-sound in a wind tunnel. The bird can sing at the same frequency as the tail-feather chirp, but its weak syrinx is not capable of the same volume. Further studies showed that the sound is caused by the aerodynamics of rapid air flow past tail feathers, causing them to flutter in avibration which produces the high-pitched sound of a courtship dive.
Many other species of hummingbirds also produce sounds with their wings or tail, including the broad-tailed hummingbird, rufous hummingbird, Allen's hummingbird, streamertail, as well as the tail of the Costa's hummingbird and the black-chinned hummingbird. However, the harmonics of sounds during courtship dives vary across species of hummingbirds.
Male rufous and broad-tailed hummingbirds (genus Selasphorus) have a distinctive wing feature during normal flight that sounds like jingling or a buzzing shrill whistle. Studies showed that the whistle arises from air rushing through slots created by the tapered tips of the ninth and tenth primary wing feathers, creating a sound loud enough to be detected by female or competitive male hummingbirds and researchers up to 100 m away.
Behaviorally, the whistle serves several purposes
- announces the sex and presence of a male bird
- provides audible aggressive defense of feeding territory and an intrusion tactic
- enhances communication of threat
- favors mate attraction and courtship
See also: List of Apodiformes by population
Hummingbirds are restricted to the Americas from southern Alaska to Tierra del Fuego, including the Caribbean. The majority of species occur in tropical and subtropical Central and South America, but several species also breed in temperate climates and some hillstars occur even in alpine Andean highlands at altitudes of up to 5,200 metres (17,100 ft). The greatest species richness is in humid tropical and subtropical forests of the northern Andes and adjacent foothills, but the number of species found in the Atlantic Forest, Central America or southern Mexico also far exceeds the number found in southern South America, the Caribbean islands, the United States and Canada. While fewer than 25 different species of hummingbirds have been recorded from the United States and fewer than 10 from Canada and Chile each, Colombia alone has more than 160 and the comparably small Ecuador has about 130 species. The migratoryruby-throated hummingbird breeds in the southeastern United States, while the black-chinned hummingbird, its close relative and another migrant, is the most widespread and common species in the southwestern United States, while the rufous hummingbird is the most widespread species in western North America.(Please see above link for complete article)
...this is brendasue signing off from Rainbow Creek. See you next time! If you are in S. Texas, hang your feeders!