410 THE ZOOLOGIST. 



such lists would require to include a large number of nests, and 

 also to extend over a series of years, since it seems that — 

 whether the cause be directly climatic, or through the food- 

 supply* — there is variation in different seasons. 



It seems probable that in the Willow-Wren, as in so many 

 other birds, the same nesting-haunts are resorted to in successive 

 seasons by the same individuals, and this no doubt applies to 

 both sexes. Where different pairs breed in such close proximity, 

 as in the present species, evidence is somewhat difficult to collect. 

 The best instance in the wood is perhaps that of pair No. 19. In 

 1908 this pair nested in a small spruce-bush, about two feet 

 from the ground. The following year (1909) the nest was built 

 amongst some prostrate grass-grown dead branches, twenty yards 

 away from that of the previous season. The 1910 site was 

 within eight yards of the 1909 one, in a similar situation, and, 

 most interesting of all, the second brood was reared in the 1908 

 nest in the little spruce-tree, which, owing to its sheltered posi- 

 tion, had remained practically intact for two years. It was 

 used by the bird without any repair beyond the addition of a 

 few fresh feathers in the lining. This adaptation of an old nest 

 in the Willow- Wren is unique in my experience. It is perhaps 

 reasonable to assume that one female was responsible for all 

 three nests. Although only eight first broods and five second 

 broods were located in the wood in 1909, it may be worth while 

 to state their relationship to 1910 nests. Excluding the instance 

 just cited, the facts are : — 



Of seven first nests in 1909, five were within fifty yards of 

 1910 sites (first nests) : 5, 6, 40, 40, 48 yards respec- 

 tively. 



Of five second nests in 1909, four were within fifty yards of 

 1910 sites (first nests) : same spot, 2, 30, 49 respectively. 



The remaining two first nests and one second nest were at 

 greater distances. 



General Habits. — Broadly speaking, male Willow-Wrens may 

 be said to pass through four stages after their arrival in their 

 breeding-haunts, each stage being marked by characteristic 

 behaviour. There is, first of all, the period previous to the 



:;: Age is another probable factor, not necessarily constant in its applica- 

 tion, since the proportion of young breeding birds may vary yearly. 



