234 
NATURE NOTES 
in their nest. I cannot absolutely vouch for the accuracy of this observation, but 
my informant was not a person likely to make a mistake. 
Bide ford, September 13, 1903. 
59. Late Nesting. — August 14 , yellowhammer, four eggs (slightly incu- 
bated) ; September 3, young greenfinches left a nest in our garden ; September 9, 
young yellowhammers in nest (ready to fly) ; September 9, young whitethroats in 
nest (about a week old). 
Bideford, September 14, 1903. 
60 . The Skuas. — Most readers will be glad to hear that this season has 
been a favourable one for the great skua, or bonxie ; I found fully 2CO pairs 
nesting on the hills on Foula Isle in Shetland, and a great number seemed to have 
hatched their young in safety. The Richardson’s skuas, however, were by no 
means so fortunate. They nest on the lowlying ground, and the heavy rains at 
the beginning of July drowned many a young bird. I found some,, indeed, which 
had been drowned before they could leave the shell, for the hollows that had 
served as nests were transformed into pools, and the water had got in at the hole 
from which the young birds had tried in vain to get out. The ordinary number 
of eggs for both the great and Richardson’s skua is two, but I was fortunate 
enough to see one nest of the latter species which contained four eggs — an event 
of which none of the Foula folk had heard before, so I venture to chronicle it. 
61 . Divers. — The capabilities of the divers on land are still the subject of 
much dispute. Their legs are placed so far behind in order to give them the 
utmost ease in swimming that it is doubtful whether it is anatomically possible for 
them to stand upright. While in the Shetlands I found a pair of black-throated 
divers nesting on a small island in one of the innumerable lochs. The approach 
to the nest was over a sloping piece of smooth, bare rock, and I watched one of 
the birds through a pair of binoculars as it went to its nest. As it was not more 
than sixty yards from where I lay concealed I had a splendid view, and felt 
almost certain that the bird straddled up over the rock somewhat after the manner 
of a duck, except that its neck was stretched awkwardly forward. The body 
appeared not to touch the ground during the whole process. I could hardly 
believe my eyes and frightened the bird off to see how it reached the water. This 
time, however, it slid down on its belly in the orthodox manner. On another 
island I found a red-throated diver sitting on its eggs. The nest was quite six or 
eight feet from the water, and being anxious to see how she would reach it I threw 
some small pebbles towards her (the nest was not thirty yards distant). Again 
I was surprised, but in a different way. The bird sprang at once into the air, and 
with a beat or two of the wing lit in the water. This was too shallow to allow 
the bird to dive, but it submerged itself as far as possible, and remained absolutely 
motionless for nearly a minute watching me. Then it swam out and dived. 
Bideford, A. J. R. Roberts. 
September 14, 1903. 
62 . Diving Birds (pp. 53, 214) I have now before me my brother’s former 
note entitled, “How do they do it?” p. 56, vol. xii., and the questions he has 
raised being interesting and important, I wish to help further, if I can, towards 
their solution. 
The most difficult part of this matter is where birds slowly sink in the water 
“ without any apparent muscular effort,” as I remember seeing them do when at 
the Zoological Gardens in London some years ago. The birds were, I think, 
guillemots. One saw a bird asleep on the surface of the water, light as a feather 
as the saying is, much lighter than water anyhow at that time ; and then one saw 
him dive, or fly or sink under water. The explanation of the first two operations 
is simple compared with the third. How does a bird sink ? If we place a beef- 
steak in water it sinks. Can it be that a bird can reduce the lightness of his 
body so that its specific gravity may equal that of raw beef? It is hard to believe 
this. In the tank in which I saw birds sink, water was being driven in at one 
end, producing a current, and the birds sank slowly in a very slanting direction. 
I think they made use of the current. A fish moving in the water, by raising 01 
depressing almost imperceptibly the side fins submerges or elevates his body. 
