BIRDS’ NESrS AND SONGS. 
>83 
faculties employed. Birds build their nests badly or in unsuit- 
able places, just as men, we know too well, often construct 
houses imperfectly, or in places where they ought never to have 
been put. In high winds, eggs often drop out of rooks’ nests ; 
and a cat may sometimes stalk off with young birds from some 
unsuitably-placed nest. It would seem too elaborate, perhaps, 
to cite Mill’s sensationalism and the philosophy of experience, 
seeing that in the construction of birds’ nests, no evidence can 
be found to show the existence of anything beyond the reasoning 
and imitative powers that animals are admitted to possess. 
They make use of the things they hnd at hand, or that they 
may themselves be able to supply, just as we expect human 
beings to do. Swallows, swifts, and song-thrushes use their own 
saliva in building their nests ; and the thrush’s nest, when well 
built, is quite a work of art, and well worthy of notice, as I can 
myself testify, after having carefully watched the building of a 
perfect beauty of a thrush’s nest, for two successive years, in my 
own garden on the banks of the Thames. After placing, first 
of all, a fundamental structure, with a hollow about the size of 
a teacup, largely of moss and such soft substances, wrought 
into a rounded form by intermingled straw, or small roots, or 
stems of grass, there was put in, by the thrushes, at the brim, a 
thicker band hooped round like the mouth of a basket. All this 
was carefully intertwisted and delicately fastened into proper 
positions here and there by the bird’s own saliva, which made a 
nice nest of the cup itself ; but at last there came the laying on 
of a lining, which made the finest part of the work. Within 
the cup, the bird first laid on, and fastened to the frame by his 
glutinous matter, a layer of mingled mud and horse-dung, 
thicker at the bottom and thinning out towards the top, all 
rounded with amazing smoothness by the thrush’s bill. For 
innermost coating, short slips of rotten wood were used, firmly 
glued on by the same cement, and bruised flat so as to thoroughly 
accord with the smoothness of the surface whereon it was laid. 
When thus finished, the lining was like pasteboard, hard, 
smooth, tough, and watertight, while thoroughly warm and com- 
fortable, furnishing a structure admirably fitted to protect the 
eggs during the bleak winds of early spring. 
All this I observed \vith as much care as I could, without at 
all disturbing the birds. With them I had, at last, got so 
familiar that the hen-bird would let me stroke her back as she 
sat on the eggs. They had chosen a pleasant spot for their 
nest and as I was very careful to keep all cats away from the 
garden, it was a very safe one. It was the same pair that built 
the second nest, which was near the first one ; but the birds, I 
noticed carefully, made no attempt to repair the former nest, as 
rooks would have done. And I thought the second nest was, in 
some respects, a little better than the first, as if the builders had 
learnt something in the year. 
And as I watched all this, I could not help thinking that 
