Straight-billed Woodcreeper Dendroplex picus Scientific name definitions

The Straight-billed Woodcreeper is common in open woodland, scrub, and river edge forest. Its very pale, straight bill and face and throat are the most distinctive features, but visual separation from other species, particularly Zimmer's Woodcreeper (Dendroplex kienerii), can be challenging. The song is subtly diagnostic, a fast accelerating and descending trill given throughout the day. Individuals or pairs forage along smaller trunks and limbs at lower levels, often joining mixed-species flocks. This species is widespread, and is distributed from Panama south through central South America and to northeastern Brazil.

18–22 cm; male 34–42 g, female 33–45 g (mainland), female 51 g (altirostris). Slim, medium-sized woodcreeper with a distinctive bill combining straight culmen with upward-sweeping lower mandible. Nominate race has indistinct whitish eyering (most evident below eye) and weak supercilium contrasting with dusky postocular stripe, brown auriculars with bold buffy-white streaking; forehead whitish; crown and nape dark brown to blackish with buffy-white streaks, these increasing in size and length on nape; back, scapulars and lesser coverts warm olive-brown to reddish-brown, with at most a few fine streaks on upper back, remaining wing-coverts mostly rufescent; lower back, rump, remiges and tail rufous-chestnut; primaries and outer secondaries tipped dusky brown, these tips increasing in extent on outermost primaries; central rectrices darker than outers, thus contrasting with rump; chin and throat buffy white, feathers of throat narrowly fringed dark brown to black, indistinct malar stripe separating buffy submoustachial region from throat; lower throat and upper breast with oval centres of feathers pale buff surrounded by black fringes that continue uninterrupted around tip, resulting in boldly scaled appearance; remaining underparts brown, sometimes more olive on belly; scaling of upper breast becomes narrower and more linear on lower breast, upper belly, sides and flanks, leaving belly largely unmarked but undertail-coverts again have buffy-whitish streaks; underwing-coverts cinnamon-rufous; iris reddish-brown to dark brown; bill light greyish-horn or brownish to dull whitish (sometimes with pinkish or lilac tinge), base of upper mandible dusky or blackish, lower mandible often paler; legs and feet various shades of green, grey, bluish-grey or brownish. Distinguished from very similar D. kienerii by straighter to slightly upturned bill, more scaly pattern on breast (more oval feather centres, complete fringes), more brownish or olive cast on belly, more rufescent tone of lesser coverts, proportionately shorter wings and tail, also by differences in vocalizations. Also similar to X. obsoletus but bill slightly paler and less decurved, back and underparts less boldly and less extensively streaked, overall coloration more rufescent (less olive), and vocalizations markedly different. Sexes similar. Juvenile similar, but plumage darker overall with patterns more muted, spots or streaks smaller, throat deeper buff, streaking below more extensive and deeper buff in color, and bill shorter and darker. Races vary in overall colour, face pattern, size and shape of breast spots, and throat colour. In “picus group”, populations of nominate in SE Amazonia (“rufescens”) and NE Brazil (“bahiae”) on average more rufescent and with streaking above and below both broader and more extensive, but many individuals cannot be distinguished; saturatior is like nominate but much darker, especially below, breast streaking more limited in extent, tail longer; duidae is also similar, but throat pure white, back browner, breast spotting more extensive and outlined with black, belly more strongly streaked; deltanus is similar to duidae but darker overall, with darker bill (also crown and tail darker, mantle more heavily streaked than nominate); altirostris is similar to nominate, but wing and bill longer, bill heavier and more strongly curved, spots on underparts larger, better defined and more extensive; <em>peruvianus</em> is brighter and more rufescent than nominate, especially above, with throat deeper buff. Members of “picirostris group” more boldly marked overall, upperparts paler and more rufous, whitish teardrop-shaped spots on crown and streaks on back both broader and sometimes outlined in black, auriculars and bolder supercilium wholly whitish, throat and upper breast almost pure white, feathers of lower throat having at most narrow dark fringes outlining rhomboid (not oval) centres; extimus is similar to picirostris but browner, less rufous, overall; dugandi has dark markings on head more extensively black than in picirostris , and is slightly paler than extimus but darker than picirostris; choicus is similar to dugandi, but dark markings on head weaker and less extensive, back and underparts lighter; longirostris is similar to picirostris, but larger, with bill longer and heavier, tail shorter, spots on breast wider, abdomen darker and less rufescent, and back, wings and tail deeper chestnut; phalarus is similar, but has spots on crown and nape larger, giving forecrown a lighter appearance, breast spots buffier; <em>paraguanae</em> differs from picirostris, choicus and phalarus in having bill longer, throat more extensively white, upperparts lighter, more yellowish-tinged, and relative to longirostris, underparts lighter brown.

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Occupies a variety of lowland habitats, with preference for open situations rather than forest: open woodland, wooded savanna, tropical deciduous and gallery forests, seasonally flooded forest, swamps, early-successional growth along rivers and lakes, river islands, mangroves, arid scrub, both young and older second growth, forest edge, plantations, and rural areas with scattered trees. In Panama and in N & E South America, some coastal populations largely restricted to mangrove swamps, whereas others frequent arid thorn-scrub; in rest of range seems less particular, occurring in a variety of open habitats, often near water, but regularly including cerrado, savanna and second growth. One of relatively few dendrocolaptids resident on Amazonian river islands, where it prefers mid-levels of mature forest and tall Cecropia woodland on islands that are of middle age or older. Ecological overlap with D. kienerii unclear; generally commoner than latter in more open habitats, but the two regularly occur at same sites, and even in same flocks. Chiefly lowlands in lower tropical zone below 600 m; locally in small numbers in foothills, to 1100 m in N Peru and 1400 m in Venezuela. A captive bird roosted on a vertical surface with head tucked into back feathers.

Apparently resident throughout range.

Diet chiefly arthropods, but occasionally takes small vertebrates. Stomach contents included primarily beetles, ants and insect larvae, less frequently spiders, wasps, hemipteran bugs, scorpions and pseudoscorpions, millipedes (Diplopoda), cockroaches (Blattodea), grasshoppers and locusts (Acrididae), snails, and unidentified seeds; also seen to eat flying termites (Isoptera) and small lizards. Most prey relatively small, less than 10 mm, with many items much smaller, but one stomach contained a millipede in excess of 20 mm, and another a lepidopteran pupa 20 mm long. Once seen to hammer wings off a large grasshopper before swallowing it whole. Most often encountered alone, sometimes in pairs or family groups, occasionally with mixed-species flocks (sometimes including D. kienerii). Only published account of foraging over army ants involved a pair seen at swarm of Labidus praedator, over which one bird spent most of its time in clinging to palm fronds, but once sallied after prey on nearby frond. Forages primarily while hitching up smaller trunks and branches (cactus stalks at some sites) from upper understorey to subcanopy, sometimes lower or into canopy; said to favour rough-barked trees at some sites, and more likely than most woodcreepers to investigate fence posts in open terrain. Most prey gleaned or picked from trunk surface or bark crevices; sometimes probes ends of broken branches or curled or dead leaves, or forages on arboreal nests of ants. Despite moderate overlap in diet and substrate use with others of genus at site in SE Peru, aggressive interactions characterized as “partial tolerance” noted only with larger X. guttatus; spatial separation appears to reduce conflicts with small congeners. Has been speculated that aggressive intolerance by dominant X. guttatus may prevent present species from ranging into high-ground forest.

Among the first birds to begin singing at dawn and one of the last to sing at dusk, but also sings intermittently during the day. Song in Amazonia a rapid series of c. 25–40 high-frequency notes in 2–3 seconds, begins as a few sharp stuttered notes followed by accelerating series of descending notes that slows at end, notes given slowly enough to be counted, “chip, chip, chip, dip-dip-dii-dii-di-di-di-di-di-di, dew, dew, dew” or “stit-ste-e-e-e-e-e-e-e-ee-eerp-eerp-eerp”; in N Venezuela fewer notes delivered more slowly (24 in 3·5 seconds), an initial chip followed by a series that accelerates slightly in middle and ends with a slowly repeated series of up-and-down notes, “chip, chip-chip-chip-dip-dip-dip-di-di-di-di-di-di-di, dip, dip, wik-up, wik-up, wik-up, wik”; said to be rather quiet in Panama, but sometimes gives soft trill somewhat like that of Lepidocolaptes souleyetii; when agitated, gives an extended series that speeds and slows, quality relatively similar but notes harsher. Call a single “dit”, “chip” or “tschup”; a loud trill, much like adult song but more obviously descending, is given by nestlings and juveniles apparently to keep in contact with parents.

Breeds in Apr–Aug in N Venezuela; nest with eggs in early May-early Jun in Venezuela and in Aug in Surinam; nests with young in late Jul to early Aug in Trinidad and NE Venezuela, but in late Mar, late Oct and early Dec in Surinam and E Amazonian Brazil; fledged young observed in Apr–May in NE Venezuela and late Sept in E Amazonian Brazil; otherwise, birds in breeding condition in mid-Jan in Surinam, late Jan–Nov in N Colombia and mid-Sept to Nov in Bolivia and Amazonian Brazil. Nest in natural cavity or in old hole of woodpecker (Picidae) in hollow trunk, tree cactus, dead stump or arboreal termite nest, or in gap between palm fronds, bromeliads or epiphytic orchids; also in wooden fence posts and nest-boxes (2 Majewska, A. A., and J. C. Oteyza (2013). Breeding biology of the Straight-billed Woodcreeper. Wilson Journal of Ornithology 125(1):150–158. Close ), cavity entrance 1·25–9 m above ground, floor of nest-chamber either unlined or lined with bits of bark or stems and down from seed pods or other vegetable matter. Clutch 2–3 white eggs, sometimes 1, average 25 × 20 mm in Surinam, 28 × 20 mm in N Venezuela and Trinidad; incubation by both sexes suggested by presence of active brood-patch on a male (which was also in moult). Incubation period 17 days; nestling period 17–18 days (2 Majewska, A. A., and J. C. Oteyza (2013). Breeding biology of the Straight-billed Woodcreeper. Wilson Journal of Ornithology 125(1):150–158. Close ). An instance of brood parasitism by Shiny Cowbird (Molothrus bonariensis) in N Colombia represents only documented case of a woodcreeper being parasitized.

Not globally threatened. Fairly common to common throughout much of extensive range in Panama and N & NE South America; less common and more local in regions that are largely forested, as in much of Amazonia. Estimated density 3 individuals/100 ha in lake-edge forest at site in SE Peru, where home range of one radio-tracked bird was 4 ha. A widespread habitat generalist; preference for open country, second growth, edge and human-altered environments reveals comparatively low sensitivity to human disturbance. Possibly increasing in Panama in connection with loss and fragmentation of forest, an observation that probably applies elsewhere in range. Populations restricted to mangrove swamps may be somewhat more sensitive than others. Although loss of mangroves was blamed for steep decline in Trinidad during 20th century, this species’ present abundance on the island (where now believed to be common and moderately widespread in mangroves along W coast) suggests that it may have been overlooked by most earlier workers owing to difficulty of surveying its preferred mangrove habitat. An indicator of mangrove forest in coastal regions of S Central America and South America.