Ceylon Frogmouth's existence under the veil of the dense tropical forests for a long time until Dr. Salim Ali found it at the Thattekkad Bird Sanctuary (which has since been named after him) in circa 1930. Later it was rediscovered in circa 1990 by ornithologist K. V. Eldhose, at the same sanctuary. Its occurrence, ethology, nesting, etc. This bird is best located at night by its song, which is a loud descending cackly and frog-like series of Klock-klock-klock-klock-klock calls.

0range-headed Ground Thrush (Zoothera citrina )

The Orange-headed Ground Thrush is a thrush that is common in well-wooded areas of India, China and southeast Asia. Most populations are resident. The species shows a preference for shady damp areas and can be quite secretive. They do not form flocks. Orange-headed Thrushes are omnivorous, eating a wide range of insects, earthworms and fruit. In their natural habitat, these ground thrushes nest in trees.

Large Egret (Ardea alba)

The Large Egret has pure white feathers with a pale whitish bill. It has long black legs and is also commonly refered to as the White Heron. The bird habits marshy areas. Its feathers are entirely white. The Herons food is mainly insects, frogs and small reptiles. During the mating season, the male develops a long white drooping crest and fine long feathers on the back and breast.

Crow Pheasant is common inside the Sanctuary. It is a large species at 48 cm. The head is black, upper mantle and underside are purplish black. The back and wings are chestnut brown. There are no pale shaft streaks on the coverts. The eyes are ruby red. Juveniles are duller black with spots on the crown and there are whitish bars on the underside and tail. Its nest is an untidy collection of twigs and branches where three or four glossless eggs are laid.

The Baillon's Crake is a very small waterbird of the family Rallidae. Baillon's Crake (Porzana pusilla) is a scarce winter visitor in India. Their breeding habitat is sedge beds in Europe, mainly in the east, and across Asia. They nest in a dry location in wet sedge bogs, laying 4-8 eggs. This species is migratory, wintering in east Africa and south Asia. These birds probe with their bill in mud or shallow water, also picking up food by sight. They mainly eat insects and aquatic animals.

The Banded Crake is a waterbird in the rail and crake family Rallidae. The Banded Crake is about 25 cm long. Its body is flattened laterally to allow easier passage through the undergrowth. Its breeding habitat is swamps and similar wet areas in well-wooded country across south Asia east from India, Pakistan, and Sri Lanka. These birds probe with their bill in mud or shallow water, also picking up food by sight. They forage for berries and insects on the ground, or clambering through bushes and undergrowth.

The Barn Owl is an owl in the barn owl family Tytonidae. This is one of the two groups of owls, the other being the typical owls Strigidae. Any member of the family Tytonidae is sometimes referred to as a Barn Owl. These are pale, long-winged, long-legged owls, 33-39 cm in length with an 80-95 cm wingspan. They have an effortless wavering flight as they quarter pastures or similar hunting grounds.

The Bay-backed Shrike, is a member of the bird family Laniidae. The shrikes, resident in South Asia. It is smallish shrike at 17 cm, maroon-brown above with a pale rump and long black tail with white edges. It is a widespread resident breeder in India, Afghanistan and Pakistan. It nests in bushes in scrubby areas and cultivation. Bay-backed Shrike has a characteristic upright "shrike" attitude perched on a bush, from which it sallies after lizards, large insects and small birds.

The Besra Sparrow-Hawk, is a bird of prey in the family Accipitridae. Besra is usually found in the wooded areas. Resident but nesting not confirmed from the sanctuary. It nests in trees, building a new nest each year. This bird is a medium-sized raptor (29 to 36 cm) with short broad wings and a long tail, both adaptations to fast manoeuvring. Its hunting technique is, relying on surprise as it flies from a hidden perch or flicks over a bush to catch its prey unaware.

Black Crested Baza is not uncommon, in the evergreen patches of the sanctuary. About six have been recorded constantly, of which two pairs were seen breeding within the sanctuary limit on tall trees. They move in flocks of 5 to 6 during the non-breeding season.

The Black Bittern, is a bittern of Old World origin, breeding in tropical Asia. Their breeding habitat is reedbeds. They nest on platforms of reeds in shrubs, or sometimes in trees. Their population is larger than that of the other bitterns. Seen along the banks of the Lake and even along stream banks of the sanctuary.