AVIAN GENUS CHRYSOCOCCYX 49 



Acanthiza chrysorrhoa Yellow-tailed thornbill 



Sericornis lathami Yellow-throated scrub-\\Ten 



Sericornis maculatus Spotted scrub-^^Ten 



Pyrrholaemus brunneus Redthroat 



Hylacola pyrrhopygia Chestnut-tailed heath-wi-en 



Hylacola cauta Mallee heath-wren 



Calamanthus isabellinus Rusty jfield-wren 



Chthonicola sagittata Speckled warbler 



Alalurus cyaneus Blue wTen 



Malurus assimilis Purple-backed wren 



The chief host, almost the exclusive one in some areas, is the speckled 

 warbler, Chthonicola sagittata, while the next most frequently victimized 

 fosterer is the redthroat, Pyrrholaemus brunneus. The dark, chocolate- 

 bro\\ai eggs of Chrysococcyx osculans match those of Chthonicola very 

 closely and those of Pyrrholaemus fairly well. 



Of 53 instances of parasitism amassed from published as well as 

 from unpublished sources, 34 involved CJithonicola sagittata, 9 Pyrrhol- 

 aemus brunneus, 3 Acanthiza chrysorrhoa, 2 Malurus assimilis, and 1 

 each for the other host species. In other words, 80 percent of the total 

 is of the two chief hosts, and a little over 60 percent refers to a single 

 one, the speckled warbler. 



While there is no reason to question the suitability of the regular 

 hosts as fosterers of the young parasite, there is still little in the pub- 

 lished record to document the fact that they can and do rear them 

 successfidly. As far as I have been able to learn, two of the less fre- 

 quent hosts, Alalurus assimilis and Hylacola pyrrhopygia, have been 

 recorded explicitly as having been seen rearing and feeding nestlings 

 or recent fledglings of the black-eared cuckoo. From one published 

 source and two unpublished ones I have found documentation of 

 similarly successful rearings by the speckled warbler, Chthonicola 

 sagittata. 



C. maculatus. 



The Asiatic emerald cuckoo is known to parasitize babblers, warblers, 

 and sunbirds, chiefly members of the latter two families.*' The hosts 

 listed below are taken from the literature, and I have been obliged 

 to accept some of them as published. It should be kept in mind, 

 however, that the eggs of this cuckoo and of the violet cuckoo, C. 

 xanthorhynchus, are practically indistinguishable, and the original 

 identifications were based on little more than the mere fact that the 

 observerer noted only one of the two cuckoos in the area. As far as 

 the biological implications of host choice are concerned, this makes 



^ For pertinent references to published records see: Ali 1962, p. 50; Baker 1907, 

 pp. 682, 684; 1908, p. 278; 1927, pp. 162-163; 1942, p. 195; Dewar 1925, p. 154; 

 Makatsch 1955, p. 186; Schonwetter 1964, pp. 568-569; Smythies 1953, p. 325. 



