Nesting secrets of the cuckoos

by K.G.H. Munidasa

Out of the eleven forms of Parasitic Cuckoos, which are known to occur in Sri Lanka, only five have been admitted to the island's check-list as breeding residents. The rest are migrants to the island during the winter period.

A sixth, the Indian Cuckoo (Cuculus micropterus) has meanwhile been labelled as "Status Uncertain," though "there is evidence that, occasionally, at least, it breeds in the island and "its young have been found in the nests of the Ceylon black-headed Oriole."
 

The late S.V.O. Somanader, posing the question of this elusive bird in 1967 suggested "its fosterers may be found among the Paradise Flycatcher or the Drongos, or even the Black-headed Oriole"... Cicely Lushington in her book Bird Life in Ceylon records that "an Oriole was once seen feeding a young cuckoo, which probably belonged to this species."

However, in 1982 the Ceylon Bird Club placed on record authentic evidence that proved, once and for all, that the Black-headed Oriole is the local fosterer of this cuckoo.

The best known of all resident cuckoos is the Indian Koel (Eudynamys scolopacea), which is parasitic on the two local crows, i.e. House crow and the Black crow. The koel's egg is described as grayish-green, spotted with reddish brown.

It measures 30.6 x 22.9 mm. against 36 x 27 mm. (House crow) and 42 x 29 mm. (Black crow). The crows' eggs however are said to be brighter in ground colour.
 

The Ceylon Hawk Cuckoo (Cuculus varius ciceliae) and the Pied Crested Cuckoo (Clamator jacobinus) are both parasitic species which, as far as the records prove, victimize the Common Ceylon Babbler or the "Seven Sisters".

Both of them lay turquoise-blue eggs, which tally closely with those of the host speices, but slightly the larger in size.

The Indian race of the former is said to cuckold small birds like pipits and chats, while the latter bulbuls, and various members of the Babbler family.

The breeding season of the Pied crested Cuckoo is as extended as that of its host species the Common Babbler.

At times two or even three cuckoo eggs have been taken from a single babbler's nest. They measure 24 x 19 mm. against 23.8 x 18.4 mm. of the babbler.

In 1968, the writer came upon a baby Crested Cuckoo being brought up by the Common Babblers, in the suburbs of the Ampara town. There were five to six babblers in the group, while two of them attended on the foster child, the others foraged in the undergrowth.
 

The cuckoo was unlike any young babbler (there wasn't any in evidence) that even an inexperienced bird-student would have at once noticed the difference in coloration, while it sat there on a sprig demanding food from the two foster parents. It was gray and buff-white with dirty white wing patches (white in the adult cuckoo) clearly visible on the side of wings.

Since the adult Ceylon Drongo Cuckoo (Surniculus lugubris stewarti) closely resembled the Ceylon Common Drongo, it was formerly believed that it deposited its eggs in the nest of that bird. However, W.E. Wait later obtained authentic evidence that went to prove that in its breeding habits the Drongo Cuckoo victimized the Black-fronted Babbler.

In 1917 wait recovered a nest of this babbler from the Puttalam district, tenanted by a nestling of the Drongo Cuckoo. On a previous occasion, too he had taken a strange egg from a nest of the same species of babblers, which he tentatively assigned to the this cuckoo.

In June 1970, at an old village not far from the Hingurana sugar factory, the writer happened to examine a nest of the White-throated Babbler.

It contained a clutch of three speckled eggs of which two were identical in all respects, but the other was seemingly different in shape, being very elliptical.
 

Later a thorough examination of the two egg specimens under a bright light revealed, though the ground colour of both was white, the strange egg gave out a pink glow, the other being chalky-white. The first egg measured 16 x 13 mm. against 18 x 13 of the other.

Henry gives the measurement of the egg of White-throated Babbler as 18 x 13.7 mm, and glossy-white in ground colour, with speckles of brownish-red. In May 1975, Shirley Perera of the Department of Wildlife Conservation watched a juvenile of the Drongo Cuckoo being fed by this species of babblers in the jungles of Mullegama off Inginyagala.

It is also on record that about 50 years ago a nestling of the Drongo Cuckoo was found in a nest of the White-browed Prinia -a member of the warbler family, not much larger than the Ceylon Tailor Bird.

The White-browed Prinia builds a small pouched-shaped nest out of grass strips, domed over at the top, and attached to a grass tussock or low branch.

Its egg is coloured a rich turquoise-blue, with spots and blotches of chocolate-brown. G.M. Henry suggests that the Drongo Cuckoo may also possibly lay its eggs in the nest of the Ceylon Iora, which builds a cup-like nest, usually in an open dead branch in the forest canopy. Its egg is described as matt-white, with markings of slaty-grey and brown.

The Ceylon Bay-banded Cuckoo (Cacomantis sonnerati waiti) is a race peculiar to Sri Lanka, whose breeding is practically unknown. However, it is believed that this race of cuckoos generally laid its eggs in the nests of the Orange Minivet and the Small Minivet.

"In September 1940 Cicely Lushington watched a female of the Orange Minivet feeding a fledgling of this cuckoo." The Indian race is known to cuckold various bulbuls and babblers. So most likely these birds will prove to be the normal fosterers of the local race, too.