Feather development grows, its spathe, which is where the rachis and vanes attach, continues to form. When spathe is finished developing, the calamus begins to form within the base of the spathe. The calamus is the quill of the feather, which is the bottom portion that stays mainly within the pulp cavity. From there, the feather is fully developed and will remain as such until molting occurs, causing it to fall off. Feathers fall off during molting, which occurs in the at different times through the year depending on the type of bird. Birds can molt for seasonal, reproductive and many other
Calamus Creek Bridge Calamus Creek Bridge The Calamus Creek Bridge near Maxwell, Iowa is a concrete Luten arch bridge that was built in 1905. At a cost of $900, it was built by N.M. Stark and Company, a firm which built several Luten arch bridges that are listed on the National Register of Historic Places (NRHP). The Calamus Creek Bridge was listed in 1998. It has a single span and a total length of . The NRHP nomination for the bridge asserts:Before the codification of bridge design in the state in 1913, Stark built perhaps hundreds of Luten arches throughout Iowa, in exclusive