Across this species’ vast ranges, it appears to breed in nearly every month of the year. On the basis of specimens in breeding condition (i.e., enlarged testes, enlarged ova, or presence of a brood patch), in Middle America, Colombia, and northern Venezuela breeding occurs principally from mid-March to June (Freidmann and Smith 1950, Paynter 1955, Smithe and Paynter 1963, Grant 1964, Russell 1964, ffrench 1973, Binford 1989), although Blake (1958) reported a male with the testes slightly enlarged at Chiriquí, Panama, on 2 September. The breeding season appears to be shifted slightly later, to early July, in northeastern Brazil (Lamm 1948), but it is shifted markedly later in southern Amazonia (mid-August to mid-October; Novaes 1976, Novaes and Lima 1990) and the Atlantic Forest (October to early December; Davis 1945, Belton 1984, Robbins et al. 1999).
The few nests that have been found were active in late March–mid-April (Costa Rica; Skutch 1967), mid-May (Oaxaca; Rowley 1966), and early April (Tobago; ffrench 1973), but juveniles (i.e., birds that fledged recently) have been taken March through July in Mexico (Klaas 1968, Binford 1989) and in March in Goiás (Hellmayr 1908).
Like all woodcreeper, this species nests strictly in cavities, although it is not known to excavate its own cavity. Few nests have been found, but cavity openings may be narrow (Rowley 1966) or broad (Skutch 1967). Skutch (1967) reported an active nest in Costa Rica in a cavity facing the sky 12 m above ground in the trunk of a dead palm (Euterpe sp.), Rowley (1966) reported one in Oaxaca, Mexico, in a crevice atop a slim, broken off trunk ca 7.5 m above ground, and ffrench (1973) noted that an adult was seen to enter a narrow crevice in the trunk of an immortelle (Erythrina poeppigiana) ca 4.5 m above ground. The species is reported to nest in either natural cavities or abandoned woodpecker holes (Narosky et al. 1983). These sparse data suggest that this species, like the even smaller Wedge-billed Woodcreeper (Glyphorynchus spirurus), may nest in crevices as often as or more than in strict cavities.
Almost no information. On the basis of Skutch’s (1967) monitoring of a nesting adult, a nest in Costa Rica was lined with dry leaves. Cavities may be fairly small; for example, one in logged Atlantic Forest in Argentina was < 50 cm deep (Cockle et al. 2010).
Shape: Not reported, although presumed to be ovoid.
Size: Dimensions of are, on average, between 20.0 × 14.8 mm (Argentina; de la Peña 1987) and 21.5 × 16.2 mm (Tobago; Kreuger 1967), and an egg weighs ca 2.25 g (Geffen and Yom-Tov 2000).
Color: Unmarked white throughout (Ridgway 1911, Kreuger 1967, Narosky et al. 1983).
Surface Texture: Glossy (Narosky et al. 1983).
A clutch of eggs numbers two or three (Narosky et al. 1983), a number typical for the subfamily (Yom-Tov et al. 1994, Marantz et al. 2003).
Egg Laying: o information.
Skutch (1967) reported that incubation bouts at one nest ranged from 2 to 58 min. (median=23 min.) and were separated by recesses of 7–25 m (median=12 min.). The incubating adult at this nest most often returned with a dead leaf, presumably to further line the nest. Only a single bird was noted, suggesting the female alone incubated (but see Parental Care, below).
Neither nestlings nor recent fledglings have been described.
Skutch (1967) surmised that this species “is a woodcreeper in which lasting pair ponds are not formed,” a conclusion reached because he had seen only a single bird tending a nest in Costa Rica that he had watched repeatedly. He still posited female-only care in the species three decades later (Skutch 1996). That said, Rowley (1966) reported two adults feeding young at nest in Mexico.
None reported, either in this species or in any other woodcreeper.
No information, but assuming this species follows the general pattern for passerines, then young birds molt into adult plumage roughly nine months after they fledge.