My Science School

The largest bird on the planet is, rather ironically, the flightless ostrich. It also lays the largest eggs among any living land animal. Ostriches are also the fastest birds on land with an ability to run at 70 kilometres per hour. They are found in the African savanna and desert lands, where they meet most of their water requirements from the plants they eat.

Unlike other birds, ostriches use their wings as "rudders" to help them change direction while running. Their powerful and long legs cover about 3 to 5 metres in a single stride. These legs are also rather formidable weapons. An ostrich kick can kill a human or a potential predator such as a lion! Their feet have long, sharp claws too. Ostriches live in small herds with less than a dozen birds in one herd. They mostly eat plants, roots, and seeds but also consume insects, lizards, and other creatures that are found in this harsh habitat.

Although there is a popular belief that ostriches bury their heads in the sand, this is not true. Perhaps the saying would have originated because of the bird's defensive behaviour. When faced with trouble, ostriches lie low and press their long necks to the ground as a means to become less visible. Since their plumage blends well with sandy soil, from a distance, it gives the impression that they have buried their heads in the sand.

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Did you know that bowerbirds are famous for building elaborate structures and even decorating them? Read on to know fascinating facts about the species.

The early European explorers to Australia and New Guinea thought that the elaborate structures they sometimes came across in the forests were built by Aborigines, so artistic and skilled were they. Imagine their surprise when they found that a species of bird was responsible!

The bird is called a bowerbird because of its habit of making complicated 'bowers' or places of courtship to attract and impress the females. The males spend weeks setting up and decorating their bowers. A young male may take several years to perfect the technique.

There are 20 species of bowerbirds of which the satin bowerbird of Australia builds the most elaborate bower. The remarkable structure it builds may reach up to 2.7 m in height. It may consist of a tower of twigs arranged around a central sapling or resemble a miniature house, complete with a door and thatched roof!

Other species clear an area in the forest and set up an 'avenue' or domed tunnel of sticks with just enough space for the bird to enter. Some prepare a lek or display area spread with upturned leaves or 'tiled' with rocks.

Several species give their bowers a coat of paint, using charcoal mixed with saliva or the natural pigment contained in the juice of wild berries. A piece of bark fibre or a tuft of leaves held in the beak serves as a 'paintbrush'. Not content with this, a bowerbird may bring coloured stones, feathers, leaves and flowers to add to the decoration. Iridescent insect skeletons, spider webs and snail shells serve as extra adornment.

Modern-day bowerbirds use discarded buttons, toys, empty tins, coloured straws, broken glass, and even CDs for this purpose! The floor of the bower is often strewn with an enticing bed of soft, fresh leaves.

When the male bowerbird is satisfied with his handiwork, he lures the female inside by calling loudly and when she shows interest, with a dance display. Most male bowerbirds play no part in raising the young. The female lays eggs, which she will incubate by herself. She also cares for the brood on her own.

Quick facts

• There are 20 different bowerbird species, and the males come in colours ranging from green, orange, red, yellow and black to white, olive-brown and sooty grey. Some have a brilliant crest or a ruff. Females are comparatively dull
• Bowerbirds live in tropical forests, mangroves, eucalyptus groves and savanna woodlands.
• They can imitate the calls of other species, as also machines like a chain saw.
• Satin bowerbirds may reuse and refurbish the same bower for more than 30 years.
• Different species go for different colours. The striped gardener bowerbird prefers yellow, red, and blue objects, while the fawn-breasted bowerbird favours green
• Bowerbirds may kill insects solely for the purpose of decorating Competition for females is fierce.
• The birds fight for choicest pieces, steal baubles from each other and tear apart their rivals’ bowers.
• Researchers think that they are the only animal species besides humans to have an aesthetic sense.

Picture Credit : Google 

Humans became aware of bird migration - the journey of birds between their breeding and wintering grounds - long ago. However, there's still so much we do not know about this riveting phenomenon. But thanks to science, technology, and research, we also constantly gain newer insights. Here's a look at a recent discovery.

Just like us humans who have an internal system that guides our body on when to sleep, wake up. etc., birds too have a system in place that lets them know when it is time to migrate. Apparently, they also "inherit' from their parents the direction in which they   must fly to reach their destination. Apart from this, they have "at least three different compasses at their disposal: one allows them to extract information from the position of the sun in the sky, another uses the patterns of the stars at night, and the third is based on Earth's ever present magnetic field". And it is this last aspect that the recent discovery throws fresh light on.

While research revealed decades ago that birds possessed magnetoreception - the ability to detect the Earth's magnetic field - it was not clear so far how exactly it worked. This mystery was solved when scientists recently discovered that the levels of a certain protein - named Cry4 - present in the eyes of migratory birds spike up suddenly during the migratory season. When this protein comes in contact with blue light (which is scattered in Earth's atmosphere), it leads to a chemical reaction that helps the birds sense the Earth's magnetic field.

Did you know?

During the first migration, the route gets registered in the birds' brain - apparently, this helps them navigate their subsequent journeys "with an ultimate precision of centimeters over thousands of kilometers". It means they gain an additional resource they can dip into - a mental map, as it were. But, since this absent during the first trip, even a small mistake such as veering off course could be fatal for the young birds.

The levels of a certain protein- named Cry4-present in the eyes of birds spike up suddenly during the migratory season. When this protein comes in contact with blue light (which is scattered in Earth's atmosphere), it leads to a chemical reaction that helps the birds sense the Earth's magnetic field.

Picture Credit : Google 

An elusive and rare hummingbird has been rediscovered in Colombia by a birdwatcher. The hummingbird Santa Marta sabrewing has been spotted years after it was first recorded in 2010. The news has sent ornithologists across the world into a state of excitement as they celebrate the find.

This is the third time that the species has been documented. It was first documented in 1946 and later in 2010 when the researchers captured pictures of the species in the wilderness.

The bird was spotted by Yurgen Vega during a survey of the endemic birds in the Sierra Nevada de Santa Marta. The researcher said that the sighting was a complete surprise and that he was overwhelmed with emotion when he first spotted the bird.

The hummingbird Santa Marta sabrewing, which is only found in the Sierra Nevada de Santa Marta mountains of Colombia was thought to have gone extinct by many ornithologists. This species of hummingbird has been listed on the IUCN red list of threatened species 'as critically endangered'. The bird also figures in the Top 10 'most wanted' list of the 'Search for Lost Birds' initiative of conservation organisations.

The hummingbird spotted by Yurgen Vega was male. The bird is identified by its emerald green feathers, bright blue throat and curved black bill The bird was spotted to be singing and vocalising. Scientists associate this behaviour to either courtship or defending territory.

John Mittermeier, director of threatened species outreach at the American Bird Conservancy has likened the rediscovery to "seeing a phantom".

The species is believed to live at an altitude of 1200 to 1800 metres in the neotropical forest. During the rainy season, they are known to migrate in search of flowering plants.

The Sierra Nevada de Santa Marta in northern Colombia is rich with wildlife and home to 24 bird species that aren't found anywhere else. Yet, according to scientists, only 15 per cent of the habitat is intact. The spotting of the hummingbird has further intensified the call to protect these forests which can solely aid in the conservation of the rare species dwelling there.

Armed with this information, the scientists will now focus on identifying stable populations of this species which can help them come up with conservation strategies and learn more about the bird.

What's the IUCN Red List?

The International Union for Conservation of Nature's Red List of Threatened Species is an indicator of the health of the biodiversity in the world. The global conservation status of animals, plant species and fungi are covered under this. The list indicates the conservation status of the species and helps in formulating conservation plans. It gives information such as the habitat, population size, ecology, threats the species faces and so on. At present, there are more than 147,500 species on the IUCN Red List of which more than 41.000 species figure under the "threatened with extinction" category.

What's 'Search for Lost Birds'

A joint initiative of conservation organistaions Rewild', 'American Bird Conservancy (ABC) and ‘Bird Life International’, the Search for Lost Birds' attempts to find 10 species that haven't been observed in the wild for over a decade but do not figure in the extinct category of IUCN Red List of Threatened Species.

Picture Credit : Google