Leks Runaway selection, the process that leads to extreme ornamentation of males, is described on this page by Barry Sinervo at the University of California-Santa Cruz. We talked about differences in reproductive success among male manakins. Here is a page from Cornell University describing manakins. To get an idea about sexual dimorphism, below are a typical female and male manakin. Go to the site to see larger photos.
Male manakins make a variety of non-vocal sounds as part of their display.
Give a listen. Below is a Capuchinbird, a lek-breeding bird from Amazonia. A relative of the Capuchinbird, whose breeding system is described here, is the Bare-necked Umbrellabird. The photos and story are by M. and P. Fogden, photographers and reserachers from Costa Rica.