The Rufous Hornero (*Furnarius rufus*), Argentina's national bird, is a master architect renowned for its oven-shaped mud nests, which it constructs with remarkable precision on fence posts, trees, and even buildings. This sturdy, thrush-sized bird has a plain, earthy rufous-brown plumage that blends seamlessly with the clay it uses for building, complemented by a white throat and a pale eyebrow stripe. Its special features include a strong, slightly curved bill used as a trowel to sculpt mud, and a loud, duetting call—a sharp "kree-kree" often performed in unison by mated pairs as they reinforce their territory. Unlike many birds, the Hornero often reuses and repairs its heavy nest over years, creating a durable, insulated home that protects its young from both predators and harsh South American sun.

Faits amusants

The Rufous Hornero’s famous oven-shaped mud nest is so heavy and durable that it can weigh up to 5 kilograms (11 pounds) and survive for years, often being reused by other bird species like wrens or swallows after the hornero abandons it. A quirky behavior is their duet singing: mated pairs perform synchronized, loud calls while perched together, reinforcing their lifelong bond with a song that sounds like a cheerful "tri-tri-tri." They have an unusual adaptation for nest-building—they mix mud with animal dung or plant fibers to create a concrete-like material that hardens in the sun, and they sometimes build a small entrance wall inside the nest chamber to block predators. Remarkably, these birds are so industrious that they may construct two or three nests per year, even if only one is used, as a form of territorial display.

Habitats et répartition

The Rufous Hornero is a bird of open and semi-open lowland habitats, avoiding dense forests and high elevations. It thrives in human-altered landscapes such as pastures, agricultural fields, suburban gardens, and along roadsides, where it builds its distinctive mud nest on fence posts, utility poles, and building ledges. Its geographical range spans much of central and eastern South America, from southern and eastern Brazil, Bolivia, Paraguay, and Uruguay, through central and northern Argentina, extending as far south as northern Patagonia.

Comportements & Reproduction

The Rufous Hornero is monogamous, forming long-term pair bonds that often last for life. Pairs defend a territory year-round and work cooperatively to build the species’ iconic mud nest, a dome-shaped structure with an internal chamber and a curved entrance tunnel, which is constructed over several weeks using wet clay and plant fibers. This nest serves as both a breeding chamber and a roosting site, and the pair often reuses or repairs it for subsequent broods. The breeding season spans the austral spring and summer, with the female typically laying 2–4 white eggs. Both parents share incubation duties for about 16–18 days and feed the chicks together, with fledging occurring around 18–20 days after hatching. A unique reproductive strategy is the construction of multiple nests within the territory; while one is used for breeding, others may serve as decoys to confuse predators or as temporary shelters, and the pair may raise two or even three broods in a single season if conditions permit. The social structure is primarily territorial and solitary outside of the bonded pair, though they tolerate other horneros in overlapping feeding areas during non-breeding times.

Alimentation

The Rufous Hornero is an insectivorous bird, with its diet consisting almost entirely of small invertebrates. It forages primarily on the ground, using its strong, pointed beak to probe through leaf litter, soil, and mud in search of prey such as ants, beetles, termites, caterpillars, and spiders. An interesting fact about its feeding behavior is that it often follows army ant swarms to capture insects fleeing the chaos, and it has been observed using a unique "foot-stamping" technique to disturb hidden prey from the substrate. Unlike many birds, it rarely consumes seeds or fruit, making it a strict carnivore focused on high-protein arthropods.

Couleurs

The Rufous Hornero is a uniformly warm reddish-brown (rufous) above, with a paler, buffy-brown throat and underparts, and no distinct markings or patterns. Its coloration provides excellent camouflage in its dry, open woodland and savanna habitats, blending seamlessly with the earth and dead vegetation where it forages.