Photographing a Bluebird's Nest by Reflected Light 93 open field, a Bluebird had taken it as a new and advantageous point from which to feed. As he flies down and swerves about to catch a grasshopper, his flight is marked by a quick flash of blue from his back, which is followed directly by a glimpse of the brick-red from his breast as he returns. The nest of the Bluebird presents a problem that is not as easily solved as most of those that interest a bird photographer. The nest shown in Fig. 2 was laid bare by cutting away a large piece from the side of the plum tree. This allowed free access to the eggs, and a picture was taken without difficulty. The part removed was replaced after the opera- tion, and the Bluebird's household duties continued as though nothing had hap- pened. A year after this nest was photographed another nest was selected for an experi- ment in the use of mirrors, whereby the tree was not damaged ; no possible harm came to this bird or nest, and the eggs were photo- graphed exactly as they are in nature. The nest was built in a cavity in a cherry tree five feet from the ground. The entrance was about four inches in diameter and was fourteen inches from the nest at the bottom of the hole. The tree is shown in Fig. 3, with an arrow pointing to the entrance to the nest- hole. Fig. 4 illustrates the methods used and Fig. 5 the photograph obtained. The rays of the sun were reflected from the mirror on the ground to the mirror in the entrance, then down upon the nest, back again to the mirror, and finally into the camera. In this way a reflection of the nest and eggs on the mirror in the entrance was photographed, the real nest being fourteen inches be- low where it appears in the picture. TREE CONTAINING BLUEBIRD'S NEST, SHOWING MIRROR IN POSITION
