One May morning I had spent an hour in a small wood where I am accustomed to saunter, and, coming out into the road on my way home again, fell in with a friend. "Wouldn't you like to see an oven-bird's nest?" I inquired. He assented, and turning back, I piloted him to the spot. The little mother sat motionless, just within the door of her comfortable, roofed house, watching us intently, but all unconscious, it is to be feared, of our admiring comments upon her ingenuity and courage. Seeing her thus devoted to her charge, I wondered anew whether she could be so innocent as not to know that one of the eggs on which she brooded with such assiduity was not her own, but had been foisted upon her by a faithless cow-bird. To me, I must confess, it is inexplicable that any bird should be either so unobservant as not to recognize a foreign egg at sight, or so easy-tempered as not to insist on straightway being rid of it; though this is no more inscrutable, it may be, than for another bird persistently, and as it were on principle, to cast her own offspring upon the protection of strangers; while this, in turn, is not more mysterious than ten thousand every-day occurrences all about us. After all, it is a wise man that knows what to wonder at; while the wiser he grows the stronger is likely to become his conviction that, little as may be known, nothing is absolutely unknowable; that in the world, as in its Author, there is probably "no darkness at all," save as daylight is dark to owls and bats. I did not see the oven-bird's eggs at this time, however, my tender-hearted companion protesting that their faithful custodian should not be disturbed for the gratification of his curiosity. So we bade her adieu, and went in pursuit of a solitary vireo, just then overheard singing not far off. A few paces brought him into sight, and as we came nearer and nearer he stood quite still on a dead bough, in full view, singing all the while. When my friend had looked him over to his satisfaction,--never having met with such a specimen before,--I set myself to examine the lower branches of the adjacent trees, feeling no doubt, from the bird's significant behavior, that his nest must be somewhere in the immediate neighborhood. Sure enough, it was soon discovered, hanging from near the end of an oak limb; a typical vireo cup, suspended within the angle of two horizontal twigs, with bits of newspaper wrought into its structure, and trimmed outwardly with some kind of white silky substance. The female was in it (this, too, we might have foreseen with reasonable certainty); but when she flew off, it appeared that as yet no eggs were laid. The couple manifested scarce any uneasiness at our investigations, and we soon came away; stopping, as we left the wood, to spy out the nest of a scarlet tanager, the feminine builder of which was just then busy with giving it some finishing touches.