LETTERS 



SPORADIC NESTING. 

 To the Editorfi of British Bibds. 



Sirs, — Mr. Buiiyard, in reply to iny request for information as to 

 the grounds upon which he bases his opinion that the Hobby and 

 Grasshopper-Warbler are sporadic in their nesting- habits, studiously 

 avoids any attempt to substantiate his assertions by facts. 



In reply to the points raised by his letter in your October issue : 

 I did not suggest a better definition because I was discussing the 

 term as actually applied by your correspondent to the Hobby and 

 Grasshopper- Warbler. I did not mention Hawfinch because I agreed 

 that this species was, like the Crossbill, a sporadic breeder in England, 

 though in a very different degree. Mr. Witherby has ample grounds 

 — after the latest irruption of the Crossbill as a breeding species in 

 England, in conjunction with previous authentic records — to term this 

 species " sporadic " ; but the cases of Hobby and Grasshopper- Warbler 

 are totally different, and, I submit, still require to be proved. 



In my opinion " sporadic," as applied to the nesting of wild birds, 

 implies " irregular in occurrence, as the result of nomadic tendencies 

 or of impulse." Thus, I should describe as sporadic the nesting ot 

 Pallas's Sand-Grouse and Crossbill, and the appearances of the clouded- 

 yellow butterfly in England. 



The dictionary assigns such meanings to the word as " single," 

 " separate," etc., but such scarcely seem to apply to the context, 

 otherwise all birds which were not gregarious would fall under this 

 head — excluding Crossbill and Hawfinch as semi -gregarious, or at 

 least social, while including Hobby. 



In deducing generalities from statistical records, due allowance must 

 be made for various appearances and disappearances seemingly within 

 the above category. Thus : First appearances are not per se sporadic, 

 as some young birds will select new breeding-places. Or, a bird may 

 be blown out of its course and accordingly remain to breed, but here 

 the occurrence would not be primarily due to impulse or intent of the 

 bird. On the other hand, a bird may disappear without being 

 sporadic — it may have died or hav'C been shot ; and as regards the 

 survivor finding a new mate, it seems equally probable that it should 

 have gone to join a mate, as that a mate should come and join it. 

 Similarly, the fluctuations in the numbers of a species breeding in a. 



