38 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I46 



did not specify if the 8 parasitized ones that he discussed were the 

 only ones so affected. 



The lack of sufficiently comprehensive or detailed quantitative ob- 

 servational evidence makes it necessary, at least for the present, to 

 rely on the available data on multiple parasitism of individual nests 

 as our primary method of evaluating the host-parasite relations. Of 

 all the species of Clamator the one that is most revealing of evolution- 

 ary change in this important regard is the great-spotted cuckoo, C. 

 glandarius, and we may, therefore, begin with it. The data on this 

 species are as follows. 



Clamator glandarius 



Of a total of 172 parasitized nests, containing 407 eggs of the 

 cuckoo, 82 had a single one each, 41 had 2, 13 had 3, 13 had 4, 10 

 had 5, 5 had 6, 1 had 7, 4 had 8, 2 had 10, and 1 had 13. In other 

 words, some 47 percent of the nests contained single eggs of the 

 parasite. However, considering that the first cuckoo egg laid in a 

 nest was a "single" one at that time, and counting only the subsequent 

 eggs as "multiples," the total is 172 singles and 235 multiples. In 

 other words, multiple eggs were almost 50 percent more frequent 

 than singles. While this is a general condition, it does not give a 

 representative picture of the situation as it really is in any one 

 geographic fraction of the total range of the parasite. 



To make the data more comparable, we may eliminate for the 

 moment all cases involving hosts other than species of crows. Six 

 species of the genus Corvus (corone, corax, alhus, capensis, ruficollis, 

 and rhipidurus) are parasitized, and together account for more than 

 half of all the records (fig. 8). Out of 43 parasitized crow nests 

 found in Spain, Asia Minor, and Egypt (the bulk of the records are 

 from Egypt) containing a total of 54 cuckoo eggs, we find that 33 

 nests had 1 each, 9 had 2, and 1 had 3. In other words, over 75 

 percent of the nests contained single eggs of the cuckoo, and, all in 

 all, multiple eggs of the parasite were less than 25 percent as frequent 

 as were singles. 



Out of 35 parasitized crow nests from south of the Sahara — from 

 former Italian Somaliland (now a part of the Somali Republic) to 

 Nigeria and south to South Africa — only 5 had single cuckoo eggs, 

 7 had 2, 3 had 3, 6 had 4, 7 had 5, 2 had 6, 2 had 8, 2 had 10, and 

 1 had 13 ; a total of 148 cuckoo eggs for the 35 nests as compared 

 with 54 eggs from 43 nests in the Mediterranean lands. In tropical 

 and southern Africa less than 20 percent of the nests had single eggs 



