Sunbird

To describe what is sunbirds, they are small birds that come from the family of spiderhunters and have the common names: sunbird, spiderhunter. There are about 132 species of sunbirds that can be spotted in Asia, Africa and Australia. Sunbirds inhabit forests, gardens, savannas, coastal areas, open scrublands, plantations, and agricultural fields.

Several species of sunbirds clear the way for the dispersal of parasitic plants, such as mistletoe, that further reduce the production of commercially significant plants. Seven species of sunbirds (typically those that live in islands and remote or confined areas) are endangered because of expedited habitat loss (deforestation owing to the development of agriculture and industrialization).

While to say about 100 sunbird species have colourful names illustrating their good looks — ruby cheeks, blue-throat, violet-tail, purple-band, and scarlet-tuft, among others — several types just cut to the chase to mention the obvious: the superb sunbird and the beautiful sunbird. The latter lives at the Zoo's Africa Rocks experience.

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Interesting Sunbirds Facts

• Sunbirds remain active during the day that makes them call out diurnal birds

• Sunbirds can reach 0.2 to 1.6 ounces in weight and 4 to 10 inches in length. Male sunbirds measure larger than females.

• Sunbirds are brightly coloured, enveloped with different combinations of red, blue-green, purple, violet and yellow feathers. Surprisingly, Males are more deeply coloured than females (plumage ordinarily has a metallic sheen).

• Sunbirds have tubular tongue covered with bristles

• A sunbird has a thin, downward curved bill. They have a direct, quick kind of flight as a result of small wings and long tail (longer in males).

• The Diet of sunbirds is mostly on nectar. Sometimes they eat fruit, insects and spiders. Insects are a fundamental source of food for young birds (they render proteins that are crucial for growth and development).

• Sunbirds can fly n flutter in front of the flowers (like hummingbirds) or roost n rest on the branches when they extract nectar from the flowers.

• Despite sunbirds having great similarity with hummingbirds, the two are not closely linked. Same morphology is an outcome of convergent evolution: unrelated species form similar morpho-anatomical characteristics because of similar lifestyle.

• Sunbirds play a key part in the pollination of many tubular flowers (bees and butterflies are unable to reach nectar hidden on the bottom of the "tube").

• Sunbirds are sedentary birds meaning that they are not migratory. They live in the same habitats all year round and only travel short distances toward the regions that offer more food.

• Some species of sunbirds tend to reduce body temperature and lower their metabolic rate at night. State of reduced physiological activity, termed as torpor, conserves energy.

• Sunbirds make unpleasant, insect-like sounds for communication. This is one of the reasons why these birds are not well-recognized as cage birds.

• Sunbirds live in pairs or small family flocks. Males are often territorial and hostile.

• The mating season of sunbirds occurs during the wet period of the year. Made couples of sunbirds are monogamous birds i.e. they mate for a lifetime.

• Female lays one to three eggs in the purse-shaped nest constructed of moss, spider webs and plant fibres. The nest hangs and holds eggs for 18 to 19 days (until they hatch). Both parents are involved in rearing the chicks.

• Spiderhunter nests are woven baskets fastened underneath large leaves.

• The female lays up to 4 eggs.

• Outside of spiderhunters, only sunbird females incubate the eggs.

• Purple sunbird eggs incubate after about 2 weeks.

• Cuckoos and honeyguides usually spawn (lay eggs) in the nest of sunbirds.

• The life span of beautiful sunbirds is unknown, while other types of sunbird are quite long-lived, such as the amethyst sunbird which can survive for at least 16 years.

• Other sunbirds can live up to 2 to 8 years in the wild.

Reproduction & Development of Sunbird

During the Courtship, the Male sunbirds defend territories, elaborating displays to females. The Male keeps chasing until getting the female's attention. Then sings, stretches out his wings, and flicks his tail. Outside of the equatorial belt, species of spider hunters breed seasonally, generally in the wet season. Birds that reside close to the equator may breed any time of year. A few species participate in lekking, where a group of males amasses to put on a courtship exhibition in order to attract females.

Clutch Size is 1-2 eggs. Female sunbirds use leaves, twigs and cobwebs to make purse-shaped nests. Nest is held from tree branches, tightly bound with spiders' webs and bordered with feathers or vegetables down. Only female sunbirds build nests.

Only female broods Hatchlings but are fed by both female and male. They predominantly eat spiders and insects. The fledging period ranges from 14-18 days with fledgeling feeding for up to another 15 days. 

Habitat and Distribution of Sunbirds

Sunbirds mainly reside in tropical forests, savannas, scrubland and inland wetlands in Africa, the Middle East, Northern Australia and Southern Asia. They are disposed to not prefer islands and coasts. Some species migrate and travel seasonally, however only a very short distance. They are found at an elevation of 19,000 feet from sea level. Some species have conformed to stay close to human habitation in gardens and agricultural land.

Diet of Sunbirds

Predominantly, sunbirds feed on flower nectar. They consume from red and orange tubular flowers and are essential pollinators for these species. A sunbird immerses its curved bill into a flower or else punctures its base and then sips nectar using a long, tubular tongue. Sunbirds also consume fruit, spiders and little insects. While hummingbirds hover to feed, sunbirds rest on flower stalks.

Behaviour of Sunbirds

Sunbirds stay in pairs or small groups and are principally active during the daytime. They strongly defend their territories from predators and other bird species during the breeding season. Sunbirds are quite likely to be talkative birds. Their songs have mostly rattles and metallic-sounding notes.

Female Sunbird With Nest And Chicks

A Female Sunbird With Chicks is Olive-Backed.

Conservation Status

The IUCN categorizes most sunbird species as "least concern." Seven species of spider hunters are jeopardized with extinction and the elegant sunbird (Aethopyga duyvenbodei) is endangered. Populations are either consistent or contracting.

Threats To Sunbird

Threats to the species include habitat loss, human transgression, and degradation from deforestation. The scarlet-chested sunbird is contemplated to be an agricultural pest, as it spreads parasitic mistletoe in cocoa estates. Although sunbirds are extremely bewitching, they are not literally captured for the pet trade due to their specific nutritional needs.

Breeding

Breeding of sunbirds takes place during the rainy/wet season. Insects and spiders are available to feed their chicks. Generally, the laying dates are between June-October, though some breed in the winter months. The timing of egg-laying varies by location (country-by-country).

Males Territorial

Polygamy opines as a male can court two females at once. Female sunbirds solely build nests, incubate eggs, broods young, and feed chicks while male counterparts attend the nest, raise young together. The duration of the breeding cycle and the number of broods per year are not reported. 

Family Life

How is it for sunbirds to hang at home? As already mentioned, Nests are built solely by female sunbirds. They are purse-shaped, compact shelters held from tree branches with a single main entrance. A number of fibres are used in nest making, including dried leaves, grass, bark, twigs, feathers, vegetable down, plants stems, and snakeskin. It is tightly bound with spider’s silk, particularly at the entrance and where it is fastened to a branch.

The nests are often “decorated” with lichen, while some have a “porch” or sweeping “beard” of vegetation draping out from the bottom. The inside of the shelter may be softened with feathers or even human litter like paper and plastic. Within this nest, a female will lay a clutch of 1-2 fragile eggs, which she will incubate for about 15 days.

Call Songs

Beautiful sunbirds are social beings and vocalize to others in their community. Sunbirds in this genus Cinnyris have more difficult songs than other sunbirds’ simpler ones. Their varieties of vocalizations implicate advent at foraging sites and defence of territories, disclose to mates, and interact with offspring and conspecifics.

Egg and Nestling Mortality

Following are some of the reasons for mortality in sunbirds:

• Infertility (not being able to reproduce)

• Inadequate nutrition available to embryos

• Shunning, Stranding, Neglecting

• Breakage of Eggshell and embryonic death

• Adverse weather conditions damaging the nest 

Larger birds prey on the pint-sized tiny hatchlings, and sunbird eggs may be eaten up by snakes.