MATING CONTROLLED 173 



nor Reeve were subject to control, that the 

 birds wandered in all directions, and that the 

 union of the sexes were fortuitous, would the 

 result have been satisfactory? We must 

 remember that the Reeve requires more than 

 one Ruff to satisfy her sexual instinct ; we must 

 also bear in mind the possibility that the 

 functioning of her instinct may be subject to 

 some periodicity, and we ask whether, under 

 these circumstances, accidental gatherings would 

 meet all the requirements of the situation. 

 Now, manifestly, she must be in a position to 

 find males when her appropriate organic condition 

 arises. But in the absence of any system in the 

 distribution of the sexes, how could delay be 

 avoided, or how could a uniform discharge of 

 the sexual function be assured ? There is, 

 however, a system. In the first place, there 

 are the assembly grounds to which the birds 

 repair season after season ; and then, on the 

 assembly grounds, there are the territories, 

 represented, as Mr Selous tells us, by depressions 

 where the grass by long use has been worn 

 away, and each depression is owned by one 

 particular RufF. The assembly grounds have 

 the effect of splitting up and scattering the 

 birds, and the number of Ruffs at any one par- 

 ticular meeting place is limited by the territories ; 

 with the result that Ruffs fit to breed are evenly 

 distributed and always to be found in certain 

 definite pl9,ces, and the Reeves know by experi- 

 ence where to find them. 



The advantage of this territorial system is 



