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 



