6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I46 



of the blue-egg layers raises the problem of the efficiency as selective 

 agents of the relatively uniformly blue-egg laying hosts. 



Inasmuch as host adaptation is an important part of the biology 

 of brood parasitism, the picture in Clamator commends itself for 

 careful study and interpretation. This is attempted in the present 

 report. Still other biological problems, similarly apparently arrested 

 in their development as "part-way" stages in the species of Clamator, 

 concern development of plumage morphisms and of migratory be- 

 havior. Thus, in two of the four species we find geographically de- 

 limited melanistic plumage phases, more restricted in range in one 

 than in the other, but in neither has the black morph replaced, or 

 achieved reproductive isolation from, the pale, or normal, morph. 

 Also, all four species are migratory in parts of their total respective 

 ranges and not in other parts. The extent of migratory movement 

 within a single species varies from none at all to thousands of 

 miles. Geographic segments of each, not necessarily even subspe- 

 cifically distinct, differ markedly from other conspecific segments in 

 this important trait. These are also discussed with all available 

 evidence in the following pages. 



The four species of crested cuckoos comprising the genus Clamator 

 form a group of birds that still reveal much — that in other groups 

 has been concealed — in their continued progress toward greater adap- 

 tive excellence. 



PHYLOGENETIC RELATIONSHIPS 



The genus Clamator contains four species of crested cuckoos of 

 Africa, Asia, and parts of Mediterranean Europe (fig. 1) — jacobinus, 

 levaillantii, coroniandus, and glandarius. It forms a natural, easily 

 recognized group, characterized by a well-developed occipital crest of 

 elongated feathers, by a transilient mode of remigial molt, and by 

 the nares in the form of linear ovals. It agrees with the subfamily 

 Cuculinae in being parasitic in its breeding, but lacks the evicting 

 behavior pattern in its young. It agrees with the Cuculinae in most 

 other characters, but varies from that group in the direction of the 

 Phaenicophaeinae in having only 13 cervical vertebrae (14 in the 

 Cuculinae and in the other subfamilies of cuckoos), and in having 

 the muscle formula "ABXYAm" (Berger, 1960). No one has 

 proposed merging it with any other genera, and practically all of its 

 recent investigators (Stuart Baker, Berger, Friedmann, Jourdain, 

 Peters, the Stresemanns, etc.) have generally agreed that it is a 

 primitive group in its particular subfamily, the Cuculinae. This is 



