NO. 4 AVIAN GENUS CLAMATOR — FRIEDMANN 4I 



four eggs of the Cuckoo but none of her own. Occasionally a 

 Magpie manages to keep her clutch apparently intact, though unable 

 to prevent the Cuckoos from depositing an egg or two. Thus, one 

 bird was flushed from a nest with ten eggs, eight of her own and a 

 couple of Cuckoos' eggs . . ." It seems from this that Jourdain's 

 evidence was not unvarying, but still pointed to regular egg removal. 

 Mountfort (1958, pp. 54-56) has added more evidence in support of 

 this habit. He marked with indelible ink all the eggs in a number of 

 parasitized magpie nests. ". . . The notes made subsequently at these 

 nests . . . proved clearly that not only as many as three different hen 

 cuckoos were laying in one Magpie's nest but that, as more eggs were 

 laid, so the number of the host's eggs diminished. Moreover, on at 

 least two occasions the addition of one Great Spotted Cuckoo's egg 

 coincided with the disappearance of two Magpie's eggs . . ," 



The picture revealed by the present data may be viewed graphically 

 in figures 9, 10, and 11, in each of which is shown the distribution 

 of the actual records, the number of instances of each particular com- 

 bination of egg numbers being indicated in the graphs. By contrast, 

 to emphasize the scattering, uncorrected nature of this distribution, 

 the dotted line represents the theoretical arrangements we should 

 expect ideally from Lack's postulated clutch-size relationship. 



All cases falling to the left, or below, the dotted diagonal line can 

 only be interpreted as in agreement with the Lack relationship, as 

 they represent clutches of eggs either collected or observed, but in 

 all cases it is not only possible, but even probable, that had they been 

 watched for subsequent days they would have had more eggs of 

 either the host or of the parasite, or both, and would thus have moved 

 closer to the line. The cases above and to the right of the dotted 

 line are instances of disagreement with the postulated relationship, 

 and it is their frequency with relation to those that concur with the 

 diagonal line, and the degree by which they exceed this relationship 

 that indicates the lack of adjustment between the parasite and its 

 hosts. 



It may be noted that the great-spotted cuckoo is relatively well 

 adjusted in the intensity of its parasitism to magpies (fig. 12), very 

 well adjusted to crows in Mediterranean lands, especially in eastern 

 Egypt, and quite obviously little or not at all adjusted to crows and 

 starHngs (fig. 13) in sub-Saharan Africa. Because of the historical 

 accident by which this cuckoo came to be studied in Spain earlier 

 and more extensively than elsewhere, we have come to think of it as 

 primarily a parasite on magpies and, because of that, we are apt to 



