WATCHING SHAGS AND GUILLEMOTS 179 



sometimes to be the case if unmodified fish were 

 pulled up, but not if these were in a soft, porridgey 

 condition. Always, too, the actions of the parent 

 bird suggested that particular process which is known 

 as regurgitation, and which may be observed with 

 pigeons, and also — as I have seen and recorded — 

 with the nightjar. 



Cormorants, as they sit on the nest, have a curious 

 habit of twitching or quivering the muscles of the 

 throat, so that the feathers dance about in a very 

 noticeable manner, especially if that rare phenomenon, 

 a glint of sunshine, should happen to fall upon them. 

 Whilst doing so they usually sit quite still, some- 

 times with the bill closed, but more frequently, per- 

 haps, with the mandibles separated by a finger's 

 breadth or so. I have watched this curious kind of 

 St Vitus's dance going on for a quarter of an hour 

 or more, and it seems as though it might continue 

 indefinitely for any length of time. All at once it 

 will cease for a while, and then as suddenly break 

 out again. It is not only the old birds that twitch 

 the throat in this manner. The chicks do so too in 

 .just as marked a degree, and on account of the skin 

 of their necks being naked it is, perhaps, more notice- 

 able in their case than with the parent birds. I have 

 observed exactly the same thing, though it was not 

 quite so conspicuous, in the nightjar, so that I cannot 

 help asking myself the question whether it stands in 

 any kind of connection with the habit of bringing 

 up food for the young from the crop or stomach — 

 the regurgitatory process. I will not be sure, but I 

 think that the same curious tremulo of the throatal 

 feathers may be observed in pigeons as they sit on the 



