Hint Birds are warm-blooded vertebrates that live in diverse habitats and migrate to warmer countries whenever the weather changes. They have various adaptive features that help them to fly which include the presence of feathers.
The state bird of Rajasthan is The Great Indian Bustard. It is a large Bird that consists of a horizontal body and long bare legs which gives it an ostrich-like appearance and is the heaviest of the flying birds. It is associated in the same habitat as blackbuck. It is protected under the Wildlife Protection Act of India 1972 and is a large ground bird with around a height of 1 meter. It constitutes a black cap contrasting with a pale head and neck with a brownish body and black patches spotted in white. The species of Great Indian Bustard is widespread around India and Pakistan which is critically endangered in Pakistan due to lack of protection and rampant hunting. These animals make local movements and are not well understood and are known for their population dispersion after the monsoon. They are found in most arid and semi-arid grasslands, open countries with thorn scrub, and avoid irrigated areas.
Siberian Crane: It is a snow crane which is a bird and a distinction among the cranes except for their black primary feathers which are visible in flight and to breathing populations in the Western and eastern Russia and Arctic tundra. They have the longest distance migrations and are known as migratory birds with the population declining drastically due to the hunting along their migration routes and habitat degradation.
Flamingo: They are the largest living birds with an average height of 110 to 150 centimeters and a weight of 2 to 4 kilograms. Their wings coverts are red with a black restricted tape and legs entirely pink. The bacteria, toxins, and polluted water are the greatest threat to the flamingo populations which usually runoff from the manufacturing companies encroaching their habitat.
Hornbill: Hornbill is a bird that is characterized by its long and down-curved bill which is brightly colored and has a unique casque on its upper mandible. They show variation in sizes from the smallest black dwarf to the tallest Southern ground hornbill. The males are bigger than the females which varies according to their species. They show sexual dimorphism and variation in their body parts. They have a distinct feature which is supported by their powerful neck muscle and the fused vertebrae.
So, the correct answer is 'The Great Indian Bustard'.
Note: Birds vary in different sizes from the largest ostrich which is up to 2.7 meters in height to the smallest living bird which is the hummingbird that is about 5.5 centimeters in height. An albatross is the only board that sleeps while it flies.