Hummingbird are the smallest of birds and from Americas. They belong to the family named Trochilidae. Most of the species have the size 7.5-13 cm. The smallest species, humming bee weighing 0.2g or even less than 0.2g. So the name hummingbirds came from that sound that they are producing by their wings that sound is audible to human.
Evolution of hummingbird:
Hummingbirds are nectarivores. So they feed upon the flowers named,Ornithophilous. The family tree of hummingbirds tell us that they have nine main clades that define that they have close relation with nectarous flowering plants. The nine main clades are
- Mountain Gems
So these birds are spreading into new geographical areas.
Metabolism of hummingbird:
Among all the homoeothermic animals they have highest metabolism. So when food is insufficient, hummingbirds have ability to conserve energy. They can also go into an inactive state , torpor, which is most likely to the hibernation. In that state their metabolic rate slows down to 1/15th of the normal rate.
Nutrition of hummingbirds:
Hummingbirds mostly eat a vast variety of insects that include mosquito,gnats,aphids,spiders and fruit flies. So the structure of beak is suitable for catching the insects. Beaks of the hummingbirds are flexible as adaptation of feeding. Hummingbirdsalso drink nectar of certain flower to meet their energy demands ,nectar is a sweet juice present inside the flower and they can also access the quantity of the sugar in the nectar. The flowers which produce less than 10% of the sugar are rejected by hummingbirds. They prefer the flowers having high level of sugar in their nectars.
Hummingbirds exhibit sexual dimorphism and this varies among hummingbirds clades. Eggs are laid which are of white colour and the incubation period is 14 to 23 days. So incubation period depends on the type of species , activeness of female to the nest and ambient temperature. Male hummingbirds don’t have interest or take part in nesting. Many species build their cup shape nest with the shrub or a branch of tree.
Colour of feathers:
One study shows that the colour of the feathers depends on the dietary proteins .The birds eating more proteins have more colorful crown than those which eat less proteins in diet. Birdsreceiving high protein have yellower green tail feathers than the birds receiving low proteins. Most of male hummingbirds have plumage with bright coloration, this is due to pigmentation in feathers and due to presence of prism like cells in the top layers so when the sunlight hits on the feathers ,it splits into different wavelengths producing different unique colours.
Special and unique characters:
Hummingbird has special and unique characters that includes:
With the evolutionary process hummingbirds have developed a dense arrangement of retinal neurons which allow the increased spatial resolution in the visual fields of frontal and lateral aspects. Thisalso helps them in navigation processing.
Hummingbirds have the unique kidneys function because after the consumption of nectars having high amount of sodium and chloride kidneys control the electrolytes balance. It means the kidneys are highly specialized for detection of mineral quantity in the nectar. So this is the unique function of the kidney.
Hummingbirds maintain the stability in the flight as in turbulent air flow , the head position of hummingbirdsis oriented and stable. When wind flows from the side they balance their position by increasing their wings amplitude and by changing the position of tail. Due to all these features they have stable flight.
The sounds of the hummingbirds originate from the seven nuclei present in the forebrain. So these are specialized sound nuclei. Sounds consisting buzzes,chirps,squeaks and as well as whistles.
Torpor is defined as the state of inactiveness. So the metabolism of hummingbirds slows down mostly at night or if the availability offood isinsufficient. This state is for the prevention of energy reserve that they may not fall in the critical energy level. So in torpor the all body systems are maintained according to the environmental demands.
They have very long life span. So many of them die during first year of the birth in the span between hatching and fledging and those which survive may live decades or more. The longest recorded lifespan is 11 to 12 years.