BLACKBIRDS, NIGHTINGALES, ETC. 331 



this stage of the bird's domestic history, I cannot 

 tell for how long he continues to do this. Probably, 

 as in the case of the shag, and also, I believe, the 

 moor-hen, the nest is added to during the whole time 

 that the birds make use of it A nest, however, may 

 properly be considered finished from the time that 

 it is en etat to receive the eggs and the sitting bird, 

 and according to this, these two grebes must have 

 built theirs between about 8.30 A.M. on one day and 

 6 A.M. on the next. Now, in my experience, these 

 birds only work during the early morning, from dawn 

 or thereabouts, up to about 8 or 9. Possibly they 

 may begin again in the evening, or work at night, 

 but I never saw them building, or even (before it 

 was finished) near the nest, at any later time of the 

 day. That the nest I speak of was not begun till 

 after 6.30 A.M. on the one day, is practically certain, 

 for up to that time the birds were building another 

 one, so that unless, as I say, they worked on the 

 evening of that day, or in the night-time, they must 

 have begun and finished it in one morning, between 

 dawn (as we may suppose) and 8 o'clock and this 

 is what I believe. If so, it seems a remarkable feat, 

 but the swiftness with which they dive and swim up 

 with their cargoes, and the bulk of weeds which these 

 represent makes me think it possible, though I must 

 confess that all the work which I actually saw on 

 the morning in question made little perceptible differ- 

 ence in the size of the heap that was already there 

 on my arrival. 



Like an iceberg, the great mass of the nest is 

 beneath the surface of the water. It seems to be 

 woven amongst the stems of growing weeds or other 



