SEXUAL SELECTION 529 



ease of one of a pair would leave the other free and single; 

 and there is reason to believe that female birds during the 

 breeding season are especially liable to premature death. 

 Again, birds which have had their nests destroyed, or 

 barren pairs, or retarded individuals, would easily be in- 

 duced to desert their mates, and would probably be glad 

 to take what share they could of the pleasures and duties 

 of rearing offspring although not their own.' Such contin- 

 gencies as these probably explain most of the foregoing 

 cases.' Nevertheless, it is a strange fact that within the 

 same district, during the height of the breeding season, 

 there should be so many males and females always ready 

 to repair the loss of a mated bird. Why do not such spare 

 birds immediately pair together? Have we not some reason 

 to suspect, and the suspicion has occurred to Mr. Jenner 

 Weir, that as the cotirtship of birds appears to be in many 

 eases prolonged and tedious, so it occasionally happens that 

 certain males and females do not succeed during the proper 

 season in exciting each other's love, and consequently do 

 not pair? This suspicion will appear somewhat less im- 

 probable after we have seen what strong antipathies and 

 preferences female birds occasionally evince toward par- 

 ticular males. 



' See White ("Nat. Hist, of Selborne," 1825, vol. 1. p. 140) on the exist- 

 ence, early in the season, of small coveys of male partridges, of which fact 

 I have heard other instances. See Jenner, on the retarded state of the genera- 

 tive organs in certain birds, in "PhiL Transact.," 1824. In regard to birds 

 living in triplets, I owe to Mr. Jenner 'Weir the cases of the starlings and 

 parrots, and to Mr. Fox of partridges; on carrion-crows, see the "Field," 1868, 

 p. 415. On various male birds singing after the proper period, see Bev. L. 

 Jenyns, "Observations in Nat. Hist.," 1846, p. St. 



8 The following case has been given ("The Times," Aug. 6, 1868) by tho 

 Eev. F. 0. Morris, on the authority of the Hon. and Rev. 0. W. Forester: 

 "The gamekeeper here found a hawk's nest this year, with five young ones 

 on it. He took four and killed them, but left one with its wings clipped as a 

 decoy to destroy the old ones by. They were both shot next day, in the act 

 of feeding the young one, and the keeper thought it was done with. The next 

 day he came again and found two other charitable hawks, who had come with 

 an adopted feeling to succor the orphan. These two he killed, and then left 

 the nest. On returning afterward he found two more charitable individzials os 

 the same errand of mercy. One of these he killed; the other he also shot, but 

 could not find. No more came on the like fruitless errand." 



