This habit is common with a number of different hawks: for example, the red-tailed hawk is reported sometimes to have its nest, a bulky flat, basin-shaped structure in the crotch of a tree, "profusely and beautifully lined with fresh green sprigs of white pine, which are frequently renewed during incubation and during the earlier stages in the growth of the young." The golden eagle is said to add green grass, or green leaves often attached to the twigs from time to time to the lining of the nest, especially after the young are hatched; and the broad-winged hawk is said to add green leaves to the lining of its nest. In quite another group of birds the same thing also occurs. A carrion crow's nest in England was visited periodically from March to August. Strangely no eggs were laid during this whole period, but the birds remained in attendance. When found, fresh sprigs of oak leaves were interwoven around the rim of the nest. On subsequent visits the oak leaves were found to have been replaced with fresh ones, and the leaves were kept fresh until late August. The purple martin supplies another example. The nest boxes we put up for them supply their main breeding places in some areas. "The parents have a habit of collecting many green leaves and placing them in the nest, a practice which may tend by evaporation to reduce the heat" in the next box. "Where large colonies are breeding they sometimes injure pear trees by stripping certain branches of their leaves," according to E. H. Forbush. A Madagascar weaverbird provides an example of decorating the nest entrance of a quite different type of nest; in this case the nest is in the shape of an inverted retort, with the entrance through the spout. The entrance is decorated with green grass heads or with green leaves, and the males keep adding fresh green decorations even when the eggs are being incubated by the female. It seems hard to believe that this is really decoration, that it is not for some purpose--either connected with the raising of the young, or more probably a leisure or substitute activity--something to keep the bird busy and strengthen the bond between bird and nest when it is not otherwise directly occupied with nesting activities. CURIOSITY IN BIRDS [Illustration] Being unable to ask birds questions that will receive answers, we have to judge their motives from appearances. And from the way some birds act curiosity seems a strong motivation at times. They show a disposition to inquire into things, especially strange things.