THE BIRDS OF AUSTRALIA. 
birds are very active morning and evening, when they may be seen gliding 
among the branches, and remind one very much of large white butterflies 
They commence to lay about the lOth November, from which date until 
the end of the month most of the females lay. Some seasons no eggs are 
found before the end of November, in which case the majority lay from between 
that date and the 25th December. However, it is not uncommon to find eggs 
much earlier or later than the above mentioned dates. 
“ White Terns lay one egg only, alwa3^s on a pohutukawa tree {Metrosideros 
villosa), and as far from the ground as possible. Sometimes they lay on the 
high lateral branches of a large upright tree, when two or three birds with eggs 
may be seen close together, but on different branches, for they are not very 
sociable birds ; but more generally they are found singly, near the tops of long 
thin, leaning trees, especially those leaning over a steep hillside or deep gully, 
fuUy exposed to the wind. It is, in fact, on such trees that about three- 
fourths of the birds lay. They make no nest of any kind, but lay their egg on 
the bare stem or branch, wherever there is a little flat place or any inequalit}?^ that 
will keep it from rolling off. They almost always lay on the main stem of 
the leaning trees, and rarely where it is less than 4 or 5 inches in diameter, 
though I have on three or four occasions seen an egg on a stem which was not 
more than about 3 inches thick. One egg was about 50 feet from the base 
of the tree, which was not more than 18 inches in diameter. I have in my pos- 
session a branch, 2J inches only in diameter, on which I found an egg. This is 
by far the smallest branch I have seen an egg on. These birds do not seem to 
mind whether the branch or stem on which they lay is level or not. Usually 
it is fairly horizontal, but sometimes it is very steep, occasionally, I should 
say, at an angle of 30° or 40°. In short, almost any place seems suitable, 
provided there is some inequality that will prevent the egg from rolling off 
while the tree is fairly still. Should the bird leave the egg, however, when 
there is only a slight wind blowing, the egg is likely to fall. I have seen it 
do so sometimes. A suitable place for the egg may be formed by two slight 
ridges running somewhat spirally round the branch, in which case the egg is 
placed between them : or a little flat place where a branch forks laterally is 
sometimes used : or the egg may be laid on the side of a stem or branch, 
and merely supported by a bit of stout bark. Once I noticed an egg placed 
between a strip of bark and the side of a thin stem. The strip of bark was 
about 18 inches long and I| inches wide. It was attached to the stem at one 
end only, the other being about 3 inches clear. The egg was placed about 
6 inches from the secured end, where there was a gap between the bark and 
the stem of fully haff an inch. I could give many other cases of finding 
eggs in most precarious positions. 
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