Rufous Hornero Furnarius rufus Scientific name definitions

Rufous Hornero are residents of second growth scrub and pastureland from central Brazil west to Bolivia and south to southern Argentina.  Noted more for their distinctive nests than for their appearance, Rufous Hornero are large ovenbirds with rufescent brown upperparts, light rufous supercilia, and tawny breast and underparts.  Rufous Hornero feed predominantly on insects such as beetles, crickets, ants, and termites, which they capture while foraging on the ground.  Rufous Hornero are incredible architects that build domed nests out of mud and straw; these nests  are 20 to 30 cm in diameter and 20 to 25 cm tall.  The nests of the Rufous Hornero are almost never reused by the pair that built them, making these nests readily accessible to other birds and animals as nest locations and shelter.

16–23 cm; 31–65 g. Large ovenbird with medium-length, nearly straight bill. Has poorly defined light rufous super­cilium , loral area and malar area, slightly darker auriculars; forehead rufous-brown, blending into dull brown crown; more rufescent hindneck; back and rump rufescent brown with some paler edgings, uppertail-coverts rufous; wing-coverts and secondaries rufescent brown, bend of wing pale buff, primaries dull brownish with light rufous wingband; short tail slightly rounded to nearly square, mostly dark rufous; throat whitish, blending to pale vinaceous tawny on breast, to paler buff belly ; flanks darker, more tawny, undertail-coverts buffy whitish with concealed dull brownish bases; iris rufous-brown to cinnamon; upper mandible fuscous to greyish or dark brownish-horn, lower mandible pale horn to pinkish with dark tip; tarsus and toes greyish, brownish or blackish. Sexes alike. Juvenile is paler below. Race <em>albogularis</em> is smaller, with darker, greyer crown, more conspicuous broader reddish collar, much more ochraceous below; <em>commersoni</em> is like previous but collar even broader, back redder, belly paler, less ochraceous; paraguayae differs from last in more rufescent forehead and nape, has less greyish underparts.

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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.

Second-growth scrub, pastures and agricultural land; a variety of open habitats, particularly disturbed areas with bare soil; second-growth scrub, pasture and agricultural land, also urban parks and gardens. Especially common near human habitations . Mostly in lowlands; ranges into mountains in some dry or agricultural valleys, to 3500 m.

Resident.

Arthropods and other invertebrates; also some seeds. Reported dietary items are Coleoptera (of families Curculionidae, Chrysomelidae, Elateridae, Carabidae, Cassidae, Tenebrionidae, Aphodiidae, Histeridae, Scarabaeidae), ants (e.g. Pheidole, Crematogaster, Acromyrmex), termites (Isoptera), lepidopteran larvae, grasshoppers (Acrididae), Hemiptera, worms  (Annelida), spiders, and snails (Planorbis); ants seem particularly well represented in stomach samples. Recorded preying on small lizard  . Nestlings fed with crickets (Gryllidae), mole-crickets (Scapteriscus), coleopteran and lepidopteran larvae, Annelida, spiders. Solitary or in pairs; occasionally, or perhaps locally, associates with foraging groups of Chalk-browed Mockingbirds (Mimus saturninus). Forages while walking. Gleans invertebrates  and some seeds from bare ground and leaf litter, very rarely from trunks and branches.

Song a long, rhythmic, raucous burst of loud, sharp “kweep!” notes, trails off towards end but often with some slower, emphatic, complaining terminal notes; often in duet . Calls include sharp “jeet!”, “jeah” or “krip”, often in series.

Season largely during austral spring-summer; eggs in Sept–Dec and nestlings in Oct to mid-Jan in Argentina; nestlings in Oct–Jan in S Brazil; frequently double-brooded. Monogamous; paired throughout year, often lifelong pair-bond. Nest a large globular “adobe oven” 20–30 cm in diameter, 20–25 cm tall, walls typically 3–5 cm thick, made of clay, mud, some dung, and straw, weight c. 3–5 kg, orientation of entrance variable, usually facing away from prevailing wind (in some studies), occasionally two openings or with entrance at top, interior wall separating narrower vestibule from larger nest-chamber, floor of latter with bits of grasses and stems; placed up to 8 m above ground in open location on tree branch, fence post, telephone pole , rooftop or almost any structure  , occasionally on bare ground, rock, or on top of as many as three older nests, or even in or on skull of dead mammal or large tin can; building activity occurs throughout year, entire nest typically completed within 2–3 months but can be built in 15 days, sometimes more than one nest built but only one used; territory probably defended all year, size 0·25–1 ha. Clutch 2–4 eggs, rarely 5 (mean 3·5 in C Argentina), laid at 1-day intervals; incubation by both sexes, period 14–18 days; both also brood and feed chicks , nestling  period c. 23–26 days; juveniles remain in parental territory for 4–9 months, occasionally attempt to help with nest-building but attacked by parents when they do. Regularly parasitized by Shiny Cowbird (Molothrus bonariensis), eggs of which sometimes ejected. High nesting success with 2·5 young fledged per clutch in one detailed study, but only 1·3 per clutch in another study; main factor causing reduced success was starvation of nestlings, probably affecting especially the last-hatched in broods of 4; in another study abnormally high temperatures were apparently major cause of mortality. Annual adult survival rate 71%.

Not globally threatened. Common to abundant throughout range in suitable habitats, i.e. human-disturbed areas. Benefits from moderate anthropogenic habitat alteration; has expanded its distribution during 20th century, primarily as a result of deforestation. Old nests of this furnariid are used extensively by other bird species, both for nesting and as roost-sites.