216 THE ZOOLOGIST. 



where I found many birds full of voice, but not the Thrushes. 

 On the 21st, however, with the temperature 45°, and a feeling of 

 spring in the air, there was a general awakening, and this con- 

 tinued till the 29th, when another spell of cold began, and, in 

 spite of one or two fine days, silence prevailed. On February 4th 

 (therm. 28°), a cold but still day, they sang again freely ; and 

 from this time onward may be said to have continued in song, 

 with occasional interruptions, but never in the same numbers, or 

 with the same noisy vociferation, as in the autumn. 



The conclusions to be drawn from these observations are not 

 altogether clear to me ; but I may venture upon a few remarks 

 on them. 



First, as to the general conditions of voicefulness, I think it 

 may be safely said that you will not hear the Song- Thrush in 

 strong wind, nor snow, cold fog, or other uncomfortable wintry 

 weather. What really spurs them to sing is still, open weather, 

 when food is easy to get at : sunshine is not a necessity, and the 

 temperature is of no great account until it becomes really low, 

 and continues so for some days. For example, on March 25th, 

 when I was writing these notes, a bitterly cold day of snowstorms, 

 a Thrush was singing finely at 6,45 p.m., with the thermometer 

 at 26°. 



Secondly, as regards the meaning of winter song, and its 

 possible connection with breeding, the entire silence of this 

 species between January Srd and January 21st might suggest a 

 distinction between a winter song, stimulated only by the enjoy- 

 ment of food and bodily comfort, and the true spring or breeding 

 song. I do not, however, feel by any means sure that such a 

 distinction is to be drawn, without modification; I am inclined 

 to think that the great outbreak of song in the autumn was, in 

 the case of mature birds at least, a forecast of the coming breeding- 

 season. This species is an early breeder, and eggs have been 

 found as early as February 28th*: and the silence in January 

 might have been accidental, or have occurred at another time, 

 according to the weather, just as it may also sometimes be noticed 

 in April or May. Birds that have already lived through one or 

 more breeding-seasons must, I should imagine, have come to 

 associate the full vocal powers they have acquired with the joys 



'■' H. Saunders, ' Manual of British Birds,' p, 4 (2nd edition). 



