Sinornithosaurus form from those found on birds from the same geological deposits. The body (contour) feathers were generally between 3-4.5 cm long and included two types: the first type are formed of several filaments joined together into "tufts", similar to modern down feathers. The second type, including those on the arms, were composed of rows of filaments ("barbs") joined together along a main shaft ("rachis"), making them similar in structure to modern bird feathers. However, unlike the wing feathers of flying birds, they did not have the secondary branches with tiny little hooks ("barbules") that flight feathers have, which allow the
A Donkey, 3 Rocks, and a Bird. A Donkey, 3 Rocks, and a Bird. A Donkey, 3 Rocks, and a Bird., also known as Donkey, Bird and Rocks and Donkey, Three Rocks, and a Bird, is an outdoor 1992 sculpture by Brad Rude, installed at Catlin Gabel School in West Haven-Sylvan, a census-designated place in Washington County and the Portland metropolitan area, in the U.S. state of Oregon. Brad Rude's "A Donkey, 3 Rocks, and a Bird." (1992), installed at Catlin Gabel School between the Lower School's science room and the Art Barn, is a cast bronze and stone sculpture depicting a life-size donkey and a bird