34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I46 



mismating. So marked a change as that between the arboreal, bulky 

 nests of masses of twigs and sticks of the magpies and crows, and 

 the terrestrial nesting tunnels of the pied starling might seem more 

 than sufficient to have functioned in its impact on the behavioral 

 patterns of the cuckoos in much the same manner as an isolating 

 mechanism. However, the differences involved, real as they are to 

 human eyes, did not appear to affect the parasite. 



In this connection I may say that I have tried to find a place 

 where both the pied starling and one or more species of crows were 

 present in numbers as breeding birds and where the great-spotted 

 cuckoo also bred, but have not been able to do so. Such a locality 

 might give an observer the opportunity to study the host choice of 

 the parasite where both types of hosts were equally available. 



The matter of host nest selection appears to affect the life and 

 activities of the cuckoos only during the brief moments of actual 

 ovulation by the hens. It may be remembered that mating or copula- 

 tion by the cuckoos does not take place in or at the nests of any of 

 the hosts, and that the cock cuckoos do not necessarily even know 

 which nests receive the eggs they may have fertilized. 



While the difference between the two extreme types of egg de- 

 positories used — the open, dish-shaped, arboreal, stick nest of a crow 

 and the long earth-tunnel of a pied starling — are great, the change 

 probably was not as abrupt as it might seem. To begin with, the host 

 to which the great-spotted cuckoo's evolution has made it most ade- 

 quately adapted is the magpie, a bird which customarily makes large 

 nests of small branches, twigs, and sticks, roofed over, with an 

 entrance on one side, and usually constructed in large thorny bushes 

 or on the upper branches of tall trees. From this it was not a great 

 change for the parasite to use nests of the crow in eastern Egypt 

 and the Near East, the chief difference being that the nests of the 

 latter were open, not roofed over, but were constructed of similar 

 materials and in generally similar types of situations. From one 

 species of crow to another (from C. corone in Egypt, Iraq, etc., to 

 C. albus and others in sub-Saharan Africa) involved no vital change 

 for the parasite, but the change from these to hole-nesting starlings 

 seems quite marked. However, even this was neither abrupt nor 

 as drastic as one might assume. In former British Somaliland (now 

 a part of the Somali Republic), a somewhat intermediate stage has 

 been reported by Archer (1961, m Archer and Godman, pp. 649-659). 

 He found several eggs of the great-spotted cuckoo in nests of the 

 white-capped starling, Spreo alhicapillus, a species that builds bulky, 



