( 145 ) 



ON MR. SELOUS' THEORY OF THE ORIGIN OF 



NESTS. 



By H. E. Howard, F.Z.S. 



In his article on the Great Crested Grebe in this Journal 

 (1901, p. 339), Mr. Selous made reference to " one of two rival 

 Wheatears catching up a piece of grass in the midst of violently 

 excited movements," adding that he would recur to the explana- 

 tion of this habit. I therefore looked forward with much interest 

 to his explanation of a habit which I admit had puzzled me for 

 some years, and which, taking his observations in conjunction 

 with my own, I now feel sure is probably — if we only knew it — 

 to be found amongst the majority of species. I therefore think 

 it best to put my own observations on record, as they appear to 

 me to very much strengthen the foundation on which his 

 theory of the origin of nests is built — a theory which, to my 

 mind, now that I look back upon the same, to me, unintelligible 

 sexual movements which I have from time to time observed, 

 appears to be placed outside the category of a provisional 

 hypothesis. 



In an article on the Grasshopper- Warbler (Zool. 1901, p. 61), 

 I described the male of this species picking up a dead leaf, and 

 following the female with it in his bill, while mating. But this 

 only very tamely describes what really happens, and if it had not 

 been for Mr. Selous I should still have been satisfied with the 

 conclusion I then arrived at, viz. that it was an outward sign of 

 the one absorbing picture in the bird's mind — the construction of 

 its nest. Sexual frenzy precisely describes the condition of the 

 males of the above species at this time — that is to say, during 

 the week or so they are mating — and in every case where I have 

 closely followed their movements at this period, they have per- 

 formed the same curious ceremony, usually in the midst of 

 intensely excited and nervous actions. These movements are 

 characterized, as a rule, in the following way : The male walks 

 — you might almost say struts — along in front of the female, 



