A Streak-headed Woodcreeper (Lepidocolaptes souleyetii) calls along the river at La Selva (Costa Rica), 11/16/98. (Buff-throated Saltator in the background)
The Rufous Piha (Lipaugus unirufus) is a common lowland Cotinga that I hear more often than see (of course this is true of most Costa Rican birds!). This guy has a variety of calls/songs.