WATCHING BIRDS AT A STRAW-STACK 217 



Sometimes only about half the flock flies off", the rest 

 not appearing to care much about it ; usually a much 

 greater number does, and this often appears to be 

 the whole number, but almost always — unless, of 

 course, on the approach of a man or some other such 

 alarming occurrence — some few, at least, remain. As 

 with the starlings, these flights seem often to be abso- 

 lutely instantaneous, the birds all rising together in 

 a solid block, but this is not always the case, and the 

 cloud may be preceded by a little half-hopping, half- 

 chass^eing about of three or four individuals, whilst 

 sometimes there is, for a second or two, a very quick 

 following of one another. If this were always so, 

 and if one bird could not fly off" without others 

 following it, there would be little or nothing to explain, 

 but, as we have seen, this is very far from being the 

 case. In nine cases out of ten the birds begin to 

 come back almost as soon as they are gone ; but, in 

 spite of this, I came to the conclusion that the cause 

 of flight was almost always a nervous apprehension, 

 such as actuates schoolboys when they are doing 

 something of a forbidden nature and half expect to see 

 the master appear at any moment round the corner. 

 Though there might be no discernible ground for 

 apprehension, yet after some three or four minutes it 

 seemed to strike the assembly that it could not be 

 quite safe to remain any longer, and presto ! they 

 were gone. Afterwards it was recognised that there 

 had been no real reason for alarm, and they came 

 back, but this seemed to strike them individually 

 rather than collectively. Now it was by stacks in 

 the open fields under no more cover, as a rule, 

 than the neighbouring hedgerow, that I had noticed 



