Perhaps we should consider the kingfisher the most barbarous of all the birds which form a shelter for their home. With bill for pick and shovel, she bores straight into a sheer clay bank, and at the end of a six-foot tunnel her young are reared, their nest a mass of fish bones--the residue of their dinners. Then there are the aerial masons and brickmakers--the eave swallows, who carry earth up into the air, bit by bit, and attach it to the eaves, forming it into a globular, long-necked flask. The barn swallows mix the clay with straw and feathers and so form very firm structures on the rafters above the haymows. But what of the many nests of grasses and twigs which we find in the woods? How closely they were concealed while the leaves were on the trees, and how firm and strong they were while in use, the strongest wind and rain of summer only rocking them to and fro! But now we must waste no time or they will disappear. In a month or more almost all will have dissolved into fragments and fallen to earth--their mission accomplished. Some look as if disintegration had already begun, but if we had discovered them earlier in the year, we should have seen that they were never less fragile or loosely constructed than we find them now. Such is a cuckoo's nest, such a mourning dove's or a heron's; merely a flat platform of a few interlaced twigs, through which the eggs are visible from below. Why, we ask, are some birds so careless or so unskilful? The European cuckoo, like our cowbird, is a parasite, laying her eggs in the nests of other birds; so, perhaps, neglect of household duties is in the blood. But this style of architecture seems to answer all the requirements of doves and herons, and, although with one sweep of the hand we can demolish one of these flimsy platforms, yet such a nest seems somehow to resist wind and rain just as long as the bird needs it. Did you ever try to make a nest yourself? If not, sometime take apart a discarded nest--even the simplest in structure--and try to put it together again. Use no string or cord, but fasten it to a crotch, put some marbles in it and visit it after the first storm. After you have picked up all the marbles from the ground you will appreciate more highly the skill which a bird shows in the construction of its home. Whether a bird excavates its nest in earth or wood, or weaves or plasters it, the work is all done by means of two straight pieces of horn--the bill. There is, however, one useful substance which aids the bird--the saliva which is formed in the mucous glands of the mouth. Of course the first and natural function of this fluid is to soften the food before it passes into the crop; but in those birds which make their nests by weaving together pieces of twig, it must be of great assistance in softening the wood and thus enabling the bird readily to bend the twigs into any required position. Thus the catbird and rose-breasted grosbeak weave.