NO. 4 AVIAN GENUS CLAMATOR — FRIEDMANN 'J'J 



Melospiza melodia, in the Columbus, Ohio, area, migratory and non- 

 migratory behavior was not correlated with age, and apparently was 

 not a matter of inheritance. Thus, nine resident fathers had seven 

 resident and two migratory sons, and nine migratory fathers had 

 seven resident and four migratory sons. Among 61 males, it was 

 found that 24 remained consistently resident, 31 were consistently 

 migratory, and 6 changed from one to the other of these behavior 

 groups. Among 43 females, 5 were consistently resident, 37 always 

 migrated, and 1 changed from resident to migrant. Some years later 

 Lack (1943-44) reported on a study of partial migration in a number 

 of species of European birds, and showed that in all cases the females 

 and the young of the year showed a noticeably greater tendency to 

 migrate south in the autumn than did the adult males. 



Baker (1942, p, 4) was aware of the partial nature of the migra- 

 tion of cuckoos other than Clamator. He went so far as to conclude 

 that ". . . most genera and, indeed, most species of migratory 

 Cuckoos include a race which is more or less sedentary. For instance, 

 the Common Cuckoo, the most migratory form of Cuckoo, has a race, 

 the Klhasia Hills Cuckoo, which can hardly be called migratory at all. 

 It breeds in the eastern sub-Himalayas and spreads into the plains of 

 Burma and India in winter, while some individuals remain all the year 

 round in their summer quarters. If . . . migration has in many 

 cases been forced upon birds because of the insufficiency of food 

 supply during the breeding season it may well be, . . . that cuckoos 

 were originally tropical or sub-tropical oriental birds and their extreme 

 limits. East and West, are those to which they have extended under 

 this pressure . . ." 



In his recent (1962) survey of bird migration, Dorst noted that a 

 considerable number of species of birds are composed of sedentary, 

 migratory, and partially migratory populations, which could be looked 

 upon as "physiological races" or sections of the total population of 

 each species. From this he drew the logical conclusion that migration 

 cannot be regarded as a specific character as it really belongs within 

 the framework of populations within the species. 



In some species of other birds migration is a characteristic of one 

 race or subspecies and not of another. A case that may be mentioned 

 is the Oregon junco, a North American finch studied experimentally 

 by Wolf son (1942). This bird has a migratory and a purely resident 

 race in northern California. To test their migratory tendencies 

 Wolf son experimentally subjected groups of individuals of each kind 

 to increasing numbers of hours of light, either natural or artificial. 



