The Olivaceous Woodcreeper sings at infrequent intervals throughout the day, although song is heard most often in morning (Marantz et al. 2003). Frequency range is broad (1.67–4.97 kHz) and may be associated with bill size (Palacios and Tubaro 2000). Song varies markedly across the species’ geographic range, with six song types that fall into two groups: (1) a rapid, staccato trill or thin rattle in Middle America and northern South America (west of the Andes, along Caribbean coast of Colombia and Venezuela, and on Tobago) and (2) a rapid, alternating series of clear whistles in Amazonia and in the various outlying populations in Brazil and the Atlantic Forest.
A trill is typical of subspecies in the griseus group (see Geographic Variation). This song lasts at least 1 s and consists of a 15–30 closely spaced notes (Figure 1A). The result is a trill that may recall the song of a Plain Xenops (Xenops minutus), although its notes are not as sharp and there is no introduction. The trill’s pitch rises slightly at first, but pitch descends, and the song slows (i.e., note spacing widens), toward the song’s end (Hilty 2003, Marantz et al. 2003), which has been likened to "a watch spring suddenly running down" (Peterson and Chalif 1973). The song of S. g. griseus proper (northern South America) tends to be of longer duration, lasting 3–4 s and consisting of 20–30 sharp notes. Song of the allopatric S. g. aequatorialis falls in this song group. It is a rapid, semi-musical trill that last 3-4 s and ascends slightly before decreasing markedly in volume and pitch (Ridgely and Tudor 1994).
A series of whistles is typical of other three subspecies groups. Birds in western (S. g. amazonus) and northwestern (S. g. axillaris) Amazonia utter a 3–4-s series of 6–14 clear whistles (pew or weet) that accelerates as it rises in pitch and intensity before pitch drops at the end (Figure 1B; Hilty and Brown 1986, Ridgley and Tudor 1994), a song intermediate between songs of the griseus group and songs deeper into Amazonia. For example, the song of putative S. g. transitivus in southeastern Amazonia east of the Rio Madeira differs strikingly. It is comprised of a series of 7 or 8 breathy whistles (wheep) that descends slightly in frequency and increases in cadence 4–4.5 s duration (Marantz et al. 2003). In arid northeastern Brazil, the song of S. g. reiseri is comprised of a series of ~17 relatively soft, singled wit or weet notes or a bisyllabic whee-du notes—alone or in combination—for ~5 s (Figure 1C; Marantz et al. 2003). In the Atlantic Forest, the common song of S. g. sylviellus is a descending series of 8–10 evenly spaced clipped whistles (kwip or weep) that accelerates slightly toward its end (Figure 1D; Belton 1984, Ridgley and Tudor 1994).
A variety of additional calls are given by the various groups. A single, whistled weep or weet notes may be delivered at an interval of 1/s, with notes doubled on occasion, at least by S. g. sylviellus (Belton 1984). Howell and Webb (1995) described a short dry rattle that may suggest the common song of the sympatric Long-billed Gnatwren (Ramphocaenus melanurus). Birds may produce a dry churring or rattling on a level pitch uniform cadence (S. g. gracileus) or may begin quietly but increase sharply in intensity or cadence toward the end (S. g. sylviellus; Marantz et al. 2003).