24 DISPOSITION TO SECURE A TERRITORY 



more closely, it will be found that in nearly 

 every case they belong to the male sex. Males 

 therefore arrive before females. This does not 

 mean, however, that the respective times of 

 arrival of the males and females belonging to 

 any one species are definitely divided, for males 

 continue to arrive even after some of the females 

 have reached their destination ; and thus a cer- 

 tain amount of overlapping occurs. A truer 

 definition of the order of migration would be as 

 follows : Some males arrive before others, and 

 some females arrive before others, but on the 

 average males arrive before females. This fact 

 has long been known. Gatke refers to it in his 

 Birds of Heligoland. " Here in Heligoland," he 

 says, "the forerunners of the spring migration 

 are invariably old males ; a week or two later, 

 solitary old females make their appearance ; and 

 after several weeks, both sexes occur mixed, i.e., 

 females and younger males ; while finally only 

 young birds of the previous year are met with." 

 Newton alludes to it as follows : " It has been 

 ascertained by repeated observation that in the 

 spring movement of most species of the northern 

 hemisphere, the cock birds are always in the van 

 of the advancing army, and that they appear some 

 days, or perhaps weeks, before the hens " ; and 

 Dr Eagle Clarke, in his Studies in Bird Migra- 

 tion, makes the following statement : "Another 

 characteristic of the spring is that the males, 

 the more ardent suitors, of most species, travel 

 in advance of the females, and arrive at their 

 meeting quarters some days, it is said in some 



