Andean Ibis Theristicus branickii Scientific name definitions

Fernando Medrano and Peter Pyle
Version: 2.0 — Published May 12, 2023

Photos from this Account

Andean Ibis.
Andean Ibis.
Possible confusion species: Black-faced Ibis (Theristicus melanopis).

Black-faced Ibis has a black semi-circular mesial chin wattle and a clear, clean division between the rufous-chestnut crown and the lower face, the dividing line running behind the eye and tapering onto the nape.

Possible confusion species: Black-faced Ibis (Theristicus melanopis).

Black-faced has a rusty buff belly-patch between the gray breast-line and the black underbelly and a more extensive belly-patch.

Nestling Andean Ibises undergoing Prejuvenile Molt (left) with Definitive Basic bird (right).

Natal down appears to be primarily grayish on the crown and back and whitish on the throat, and buff underneath, mimicking later plumages. Incoming Juvenile upperwing coverts are similar to those of adult but washed brownish. Note also the slate bill with dull greenish outer half, dull brownish irises, and grayish legs in the nestlings, compared to the bare part colors of the adult.

Juvenile Andean Ibis. 

Juvenile Plumage is similar to later plumages but duller and browner in the head, neck, and breast. Note gray-brown cown and buff to whitish nape and sides of head, whitest on auriculars. Upperpart feathers dark gray tipped with buff. Upperwing lesser coverts buff with grayish centers creating scaled appearance. Note also the dull iris and bill, the latter with a dull greenish outer half.

Juvenile Andean Ibis.

Breast buff becoming whiter ventrally, some feathers often with narrow streaks. Upperwing coverts whashed brownish and with buff tips.

Formative (rear) and Definitive Basic (front) Andean Ibises.

Fresh Formative Plumage can show a dark crown resembling Juvenile Plumage, but note the prominent dark streaking to the foreneck. The head feathers and scattered back feathers have been replaced but wing coverts and flight feathers are juvenile. The Preformative Molt may be protracted and may not have yet completed in this individual.

Formative Andean Ibis.

By September the Preformative Molt has completed and the retained Juvenile back feathers, upperwing coverts, and tertials have become worn. The head feathers have been replaced and are formative, resembling later plumages but duller and with prominent streaks to the foreneck. Some scattered formative back feathers are also evident, and one secondary may have been replaced adventitiously.

Formative bird commencing the Second Prebasic Molt (rear, with wings up) and Definitive Basic (front) Andean Ibises.

In the rear bird, note that most Juvenile primaries and secondaries are retained and are narrow, tapered at the tips, and brown in comparison to those of the Definitive Basic bird. No molt clines or contrasts in wear are evident, except for the growing Second Basic inner two primaries on the right wing.

Possible Second Basic (right) with Definitive Basic (left) Andean Ibises. 

The bird to the right appear to have replaced the p1–p5 and s1 on both wings, with remaining visible remiges being juvenile, narrow, worn, brown, and not showing molt clines or contrasts. The bird to the left shows Staffelmauser molt, including a molt cline from worn basic p8 to fresher basic p10. Study is needed on the extent of the Second Prebasic Molt in this species.

Possible Third Basic Andean Ibis (lower bird)

The abraded p10s on the lower bird looks narrow and pointed, suggesting Juvenile feathers. If so, two waves of inner primaries (p1–p4 and p5–p9) may be third and second basic feathers, respectively. Secondaries s3–s4 and and s7 or s8 on each wing also could be Juvenile. Among species that can show up to four sets of Staffelmauser, this would be consistent with a bird completing the Third Prebasic Molt toward Third Basic Plumage. Study is needed on the extent of the Second and Third Prebasic Molts in this species.

Definitive Basic Andean Ibis.

In fresh Definitive Basic Plumage, back feathers, upeprwing coverts, and tertials are bluish-gray. The relatively deep tawny mid-breast and well-defined dusky and black breast collar may indicate Third Basic or an older individual. Extent of chestnut, buff, and whitish to the head and underparts shows individual variation; this one shows relatively pale buff coloration to the throat and upper breast and relatively whitish lower underparts. The basic rectrices are broad, truncate, and black in Basic plumages. Note also the dull dusky reddish legs during the non-breeding season.

Definitive Basic Andean Ibis.

Andean Ibises show Staffelmauser molting patterns, with up to four "sets" of basic primaries present, with a set defined by older outer next to newer inner primaries; the number of sets indicates minimum age. Here there are four sets on the left wing, p1, p2–p3, p4–p8, and p9–p10; note that within each set there is a cline from older and browner newer to black and glossier outer feathers. The secondaries also show 2–3 generations of Basic feathers. Note that the legs become relatively bright reddish during the courting and breeding period.

Andean Ibis commencing Second Prebasic Molt.

The Second Prebasic Molt can commence earlier than later prebasic molts due to lack of time constraints for breeding. Here three generations of back feathers are evident, with worn brown juvenile feathers, older gray formative feathers, and fresh silvery blue-gray second basic feathers. Note the streaked Juvenile foreneck and breast feathers also present. Legs can be dull pinkish during the Second Prebasic Molt.

Andean Ibis commencing Definitive Prebasic Molt.

Definitive Prebasic Molt may occur primarily in February–July. Variation in wear of back feathers indicates molt of this tract may be protracted and/or suspended but may also indicate the presence of a Definitive Alternate Plumage; study is needed. Here, some back feathers are being replaced but molt of remiges has not commenced. Three sets of basic primaries (p1–p5, p6–p7, and p8–p10) indicates commencement of at least the Fifth Prebasic Molt.

Andean Ibis completing Definitive Prebasic Molt.

Here p7 is growing and p8–p10 show a cline indicating basic feathers. Prebasic molts may be extended to September in some individuals. Further study is needed as few images are present of birds undergoing flight-feather molt it Macaulay Library .

Adult Andean Ibis. 

In adults, the bill can be dark slate to black, but sometimes tinged horn at the base and tipped dull greenish. Slit-like nostrils occur at the base. The iris is dark red, the bare orbital skin is slate, and, in adults, strips of bare black skin extend from the bill through the malar area. Legs and feet are red, perhaps brighter during breeding than during molting periods

First-year Andean Ibis. 

During the first year (while in Formative Plumage) the iris becomes warmer brown, the bill becomes darker with a smaller greenish tip, and the legs and feet can be dull dusky-pinkish to dull red. The bare skin in the malar area is beginning to be exposed.

Andean Ibis has been recorded in Los Toldos, Salta, Argentina.
Pair on its nest situated on cliff.
Pair in its habitat; Napo, Ecuador.
Birds in their habitat; Junín, Peru.
Birds in their habitat; Arica y Parinacota, Chile.
Bird foraging with Andean Lapwing (Vanellus resplendens).
Birds foraging with Andean Gulls (Chroicocephalus serranus).
Bird foraging with Puna Ibises (Plegadis ridgwayi).
Adult on nest; January, Cuzco [Cusco], Peru.
Nest is a platform of dry sticks.

Macaulay Library Photos for Andean Ibis

Top-rated photos submitted to the Macaulay Library via eBird. Note: Our content editors have not confirmed the species identification for these photos.

Recommended Citation

Medrano, F. and P. Pyle (2023). Andean Ibis (Theristicus branickii), version 2.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.bkfibi2.02