COURTING DISPLAY INSTINCTS IN BIRDS. 407 



(4) The actual building by the male bird, before the arrival 

 from overseas of the female, and in a state of sexual excitement, 

 of a nest, which, upon her arrival, she helps to finish, and in 

 which the eggs are then laid and incubated.* 



(5) The building by the male, after the arrival of the female, 

 of one or more nests, previous to the participation of the latter 

 in the work, when, by the joint efforts of both, a final one is 

 made in which the eggs are deposited.! 



(6) Actions of the female bird in nest-building, curiously 

 resembling some sexual actions of the male of another and widely 

 separated species, as a consequence of which similar actions, an 

 essentially similar result, in the case of the real and the so-called 

 " false " or " mock-nest," is produced. \ 



(7) Coition on the nest, either (apparently) invariable, or more 

 or less habitual, in the case of various species of birds, repre- 

 senting (as observed by myself) three orders. § 



(8) The catching up by the female of some part of the 

 material of the nest thus used as a pairing-place, either during 

 or immediately after coition, whilst — in the first case certainly, 

 in the second inferentially — in a state of sexual excitement. jj 



(9) Actions, similar to the above, of the female, whilst sitting 

 alone, on the nest thus used, awaiting or pending the return of 

 the male, to repeat the act of coition. M 



(10) The apparent association, in the mind of both the male 

 and female bird, of nidification and coition, as shown by (a) the 

 former activity either immediately preceding or succeeding or 

 even traversing, and, to some extent, impeding the latter ; and 

 (b) the act of taking up in the bill such material as is used in 

 making the nest, even when the birds thus acting are at a 

 distance from and out of sight of it, having become, with them, a 

 symbol of conjugal union on the nest, as shown by its being 



* ' The British Warblers,' H. E. Howard, vol. i, 1, p. 8, with plate facing 

 p. 13. 



f l The British Warblers,' vol. i, 1, pp. 11-13. 



I ' Zoologist,' April, 1902, pp. 140-1. 



§ 'Zoologist,' May, 1901, pp.162, 181; September, 1901, pp. 341, 345; June,. 

 1914, pp. 224-5. ' Wild Life,' April, 1914, pp. 211-12 ; June, 1915, pp. 177-8 ; 

 July, 1915, pp. 31, 34; August, 1915, pp. 41-2. 



|| ' Zoologist,' June, 1914, p. 216 ; ' Wild Life,' June, 1915, p. 178. 



IT ' Wild Life,' April, 1914, p. 212. 



