But the most curious nest I have ever met with was built upon a railroad cutting, where the ground had a slope of more than forty-five degrees. Such a position for a dwelling of the kind the Robin is known to build, to one not conversant with the facts, must appear incredible. But that it was accomplished, the nest itself was the monument of the builders’ thoughtful skill and labor. A semicircular wall of mud, eight inches in diameter and five inches in height, constituted the groundwork, and within the cavity thus formed was reared a coarse, substantial, bulky fabric, that was entirely composed of the stems of grasses, leaves and roots, loaded down and held in place by pellets of mud. [Illustration: Copyright 1900 by A. R. Dugmore. NEST FROM THE TOP. SECTION OF TWO-STORIED NEST. RED-EYED VIREO’S TWO-STORIED NEST WITH COW-BIRD’S EGG BENEATH] A more remarkable position, and one that seemed as difficult to manage, I shall now relate. Few birds care so little for position as the common House Wren. Almost any place answers its purpose. Near the little town of Thornbury, in the State of Pennsylvania, a pair of these birds, in the summer of 1882, took possession of a derrick, and, as a site for a home, selected the space over a sheave in one of the stationary blocks, where, in due time, was deposited their rude, yet comfortable, nest of sticks and feathers. A similar structure occupied the spot the previous year, and a brood of eight birds was raised. It was not the elements of composition of these nests that excited interest and surprise, for they are not materially different from the usual form, but the strange, anomalous situation which they occupied. So dexterously were the materials arranged within the space that the revolution of the wheel was not in the least interfered with. The nest was approached on the side facing the rope that moved the pulley. The opposite side could have been used for this purpose, and doubtless with less danger to life or limb, but preference seemed to be shown for the other. Why this was so was for some time a mystery. But when the birds were seen to alight upon the rope at the top of the derrick and ride down to the nest, the explanation at once became apparent. Never did linnet enjoy the rocking twig, or bobolink the swaying cat-tail, with half the zest than did these eccentric creatures their ride down the rope. A hundred times a day, when necessity arose, they treated themselves to the pleasure, the rope all the while moving at the rate of thirty feet in a second. Six of the seven days, from early morn till night, they availed themselves of this strange conveyance, and never a danger occurred to mar their delight. In due time a family of happy, rollicking children was raised, and the nest on the derrick deserted.