in nest building than the adults. The materials used are not only different but the nest is quite often swung loosely to the twigs above, so that it is at the mercy of every wind. The material used by the young birds for the construction of the nest is mostly coarse vegetable fibre and they seldom line their first home. The older birds, however, discover that twine , horsehair etc. make a much stronger and neater wall for their home and also that fluffy chicken feathers and bits of cotton batting are excellent lining. They are quite expert in concealing their nest by bringing down green leaves and tying them about the outside. This is so well done that to a casual observer it would appear only as a thick bunch of foliage. The older birds often do most excellent weaving and I have taken one nest composed entirely of horeshair, the sides being as smooth as a piece of camel's-hair goods. This nest is heart-shaped and has a circular opening at one side of the top, which has a diameter of only 1.65 inches, hardly large enough to admit the birds. The nest is four inches deep and four inches across inside, and is lined with soft chicken feathers and cotton batting. The quills of the feathers are pushed through the sides of the nest so that they will keep their places.
Until the season of '97 I have never known the Bullock's Oriole to use palm-fiber in the construction of its home, but I found a nest May 11,in a peach tree, composed entirely of this fiber. It was well lined with chicken feathers and placed between several small branches. A pair of Bullock's Orioles built a nest this year in an almond tree near the porch, and I had an excellent opportunity to watch them while they were at work. The place chosen was in a wide fork between four small branches. Both birds worked on the nest and as soon as they had loosely formed the walls or framework, one of them worked inside and the other outside. The latter would bring a horse-hair or a piece of twine in its beak and pass the end through the wall of the nest to his mate inside who took the end and passed it out again through another place. In this way the nest was soon woven quite smooth and looked as if it had been made with a darning needle by hand. This nest is very peculiar in shape, the sides being woven to the surrounding twigs which makes the opening at the top very large and causes the nest to look like a double one. The opening is six inches long and three inches wide and the nest is five inches deep inside. It is difficult to find two nests of the Bullocks' Oriole alike in shape or material, as they use almost anything they can find in the way of fiber.
The nests of the Arizona Hooded Oriole on the other hand are very much alike, and I have never found one made of other material than the palm- fiber. The locations, too, are similar, a tree with large leaves being usually selected and a favorite position is under the broad, corrugated leaves of the palm. These form an excellent shelter from both rain and sun. They drill holes through the thick leaves with their sharp, slender beaks and tie the nest to them with palm-fiber. Often the first is hung between several leaves such as those of the fig tree, when holes are cut and the palm-fibers laced in and out through them, thus drawing the leaves together to form the outside of the nest. The leaves not only aid in the nest structure but also form the best possible concealment. An average nest of Arizona Hooded Oriole is 3.50 inches deep and 2.50 inches wide inside measurements, whi!e the outside is about four inches deep and four across. Nests of both the Bullock's and Arizona Hooded Orioles are frequently taken possession of by House Finches, sometimes even before the orioles have finished them, but more often after they are deserted. When the House Finches take possession of the nest they re-line it with
