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 difference 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
