Macro invertebrates like insects, worms and mollusks, mainly spotted in aquatic habitats are found in vast variety and in huge number in comparison to other group of organisms. These organisms are an important part of the functioning of the ecosystem and the food chain as they are the food of a number of animals, birds and fishes. The land insects found here in great numbers are good for the breeding of land birds.
Popular as ‘Bird Paradise’, Keoladeo National Park is home to more than 370 species of birds. For ornithologists, the park has 2 important aspects- one important aspect is its location that is a favorite of the migratory waterfowl that comes here in the Indian subcontinent before it goes to the different places. These bird species meet here before they leave for their breeding grounds in western Palearctic region. Along with this, a huge flock of waterfowls can be seen at the wetland area. This area is also a customary wintering area of India where one can find the endangered Siberian crane.
As far as landbirds are concerned, one can find a collection of bee-eaters, warblers, quails, bulbuls, partridges, buntings and chats. Other avifauna species found here include Marshall's iora and Indian grey hornbill.
The birds of prey here comprise of Pallas' sea eagle, crested serpent eagle, osprey, peregrine, spotted eagle, tawny eagle, imperial eagle and short-toed eagle. A latest advancement in breeding ground for the species of India was noticed when the greater spotted eagle was seen breeding here.
The location of the national park in the Gangetic Plain makes it a matchless breeding area for cormorants, storks and herons along with being a prime wintering area of a decent numbers migrant ducks.
The regular waterfowl birds that can found here include common sandpiper, shoveler, wood sandpiper, cotton teal, tufted duck, gadwall, Asian open-billed stork, little cormorant, painted stork, painted stork, common teal, great cormorant, comb duck, green sandpiper, little cormorant, great cormorant, Indian shag, white spoonbill, ruff, painted stork, oriental ibis, darter, and green sandpiper. During their mating and breeding time, Sarys crane is seen doing its courtship dance.
Around 27 identified mammalian fauna species have been recorded in Keoladeo Ghana National park with Sambar, Feral cattle, Nilgari and Chital deer being the most common ones. In the crop fields of the park, while Indian porcupine and Wild boar can be frequently spotted, the 2 species of mongoose of India- common Indian gray mongoose and the small Indian mongoose are rarely seen.
Though fishing cat and jungle cat are cat species found here but small Indian civet and Asian palm civet are rarely seen here. The smooth-coated otter are generally sighted in the woodlands, attacking coot birds. Hyenas and Jackals are the predators here who consumer rodents and birds. A number of varieties of rats, bats, gerbils and mice are also seen in Keoladeo.
The diversity and population of fishes are an important part of the ecology of the park and are food for many birds. A total of 43 species of fish fauna are found here out of 37 varieties get into the park via water stream that comes from Ajan Bund and 6 of the species are breeding residents. In the monsoon months, the park gets about 65 million of fingerlings and fish fry.
The herpetofauna (amphibians and reptiles) in Keoladeo is assorted. There are around 10 kinds of turtles in the whole of Rajasthan and 7 are found here. Along with this, there are 13 species of snakes, 5 species of lizards and 7 species of other amphibians.
The wetlands in the park contain skipper frog and bullfrog. Spotting a python enjoying the sun during rains is a common site. In the burrow of python, Indian porcupine, common monitor lizard and bi-colored leaf-nose bat have also been seen. Russell’s viper, cobra and krait are the poisonous snakes found here. langurs and the Rhesus Macaques are the primates at Keoladeo.
There are not many huge predators but the smaller carnivore animals include striped hyena, Bengal fox, jackal, fishing cat, smooth-coated otter, Indian grey mongoose, jungle cat, small Indian civet, jungle cat and common palm civet. Ungulates or the large mammals found in the park are feral cattle, hog deer, blackbuck, hog deer, wild boar, chital and nilgai. Indian hare and Indian porcupine are other mammals at Keoladeo.