We spent the later part of the afternoon of Sunday, January 15, 2012, birding along Yapara Creek, a tributary of the Amazon River located below the main confluence of the Ucayali-Marañón Rivers. The Plain-breasted Piculet, Picumnus castelnau, was one of the species that we saw. Piculets are tiny woodpeckers that actively creep near the tips of vines and branches while foraging. They do not have stiffened retrices or use their tails to brace themselves. Underparts are an off-white color (with a pale yellow tinge) and upperparts are an olive-brown. Males have a black spotted red forecrown that is outlined with black. Their preferred habitat is young Cecropia forests on river islands, but they also occur in second-growth forest away from rivers. Temperatures were in the mid to upper 80's with partly cloudy skies and high humidity.