168 AGGREGATION, COMPETITION AND CYCLES 



finement with increasing objectivity. Howard (1920:73) states that 

 each male establishes a territory at the beginning of the breeding sea- 

 son, and there isolates itself from the members of its own sex. But 

 the change is carried further, so that the bird becomes openly hostile 

 toward other males with whom it had previously lived on amicable 

 terms. The seasonal organic condition is responsible for the function- 

 ing of the disposition that results in this intolerance, just as for that 

 concerning the selection of a territory. This intolerance applies also 

 to the selection of a mate. This may be summed up in the later brief 

 statement that the male "isolates himself, makes himself conspicuous, 

 becomes intolerant of other males and confines his movements to a 

 definite area" (1920:64). Nice (1933:91) would limit the term still 

 further: "territory can not mean just the nest spot when the adults 

 feed in common; this may be the 'nest territory,' but is a very dif- 

 ferent matter from a territory in its strict sense, to which the parents 

 confine themselves during the breeding season. Again the very essence 

 of territory lies in its exclusiveness; if a bird's range is not defended, 

 it is not a territory." 



The extent of territory is supposed to be determined by the space 

 available, as well as the amount of food in it; when food is scarce, 

 the area required is larger. The boundaries are apparently arrived at 

 by both direct and indirect competition, in connection with such fea- 

 tures of the terrain as watercourses, openings, trees, bushes, etc. Once 

 in possession, the male endeavors to keep all other males of the same 

 species out of the area, and when their requirements are much the 

 same, those of other species as well. Nice states that the complete 

 procedure for acquiring a territory consists of four steps, namely, 

 staking out the claim, the chase, the combat, and the final proclama- 

 tion of ownership on the part of each bird {loc. cit., page 94) 

 (Fig. 35). Conspicuousness of the male is regarded as an essential fea- 

 ture of the process, which in passerines is chiefly secured through 

 song, though the author states that the assertions made concerning 

 the latter are pure theory. She further says that the bird students 

 of the world "are in danger of going territory-mad," and it is patent 

 that the present superstructure is out of proportion to its foundation, 

 even Howard admitting in the preface of his book that much is mere 

 speculation (cf. Errington and Hamerstrom, 1936:315, 398; Allen, 

 1934) . 



In a recent study of sex rhythm in ruffed grouse, Allen (1934) 

 concludes that this has a direct bearing upon the problem of terri- 

 tory, as the following excerpt indicates: 



"Bird behavior, including the earlier arrival of males than of 



