Puna Ibis Plegadis ridgwayi Scientific name definitions

The Puna Ibis is a dark ibis of the high Andes. It has long legs, a long decurved bill, and a patch of bare reddish facial skin. It resembles the largely allopatric White-faced Ibis (Plegadis chihi), but in adult plumage lacks the white on the face and has darker legs, a darker iris, and darker body plumage. It occurs in the Andes from central Peru south through Bolivia to extreme northern Chile and northwestern Argentina. Small numbers occur along the Peruvian coast, where breeding occurs locally. It occurs in flocks in alpine wetlands and pastureland, feeding by probing in mud. The nest is a platform of vegetation placed in tall grass in a wetland.

56–61 cm; male 608–734 g, female 478–554 g (1 Dunning, J. B., Jr. (2008). CRC Handbook of Avian Body Masses. Second edition. CRC Press, Boca Raton, FL, USA. Close ). At some stages has fleshy bill, and legs can be dull red. In breeding plumage , differs from other Plegadis by darker overall colour, especially on back  and scapulars, with less chestnut; bill  and tarsi shorter. Non-breeding adult  similar, but duller above; head and neck  dark chestnut with fine white streaking . Immature as non-breeding adult, but duller above; some purple on underparts, which are more blackish than in P. chihi; dark brown iris and brownish bill.

Highlands of C Peru S to Bolivia, extreme N Chile and NW Argentina; non-breeding visitor to and local breeder (2 González, O., Tello, A. and Torres, L. (1999). El Yanavico Plegadis ridgwayi, de migratorio andino a residente de la costa peruana. Cotinga 11: 64–66. In Spanish with English summary. Close ) on Peruvian coast.

A high-altitude species , occurring on puna at 3500–4800 m. Locally it extends down to 2200 m and has been recorded nesting in coastal Peru, at Pantanos de Vila, Lima (3 Schulenberg, T. S., D. F. Stotz, D. F. Lane, J. P. O’Neill, and T. A. Parker (2010). Birds of Peru. Revised edition. Princeton University Press, Princeton, New Jersey, USA. Close , 4 Gonzáles, O., Tello, A. and Torres, L. (1999). El Yanavico Plegadis ridgwayi, de migratorio andino a residente de la costa peruana. Cotinga. 11: 64–66. Close ). It frequents swampy areas, rushy pastureland , mudflats, ponds and streams; also coarse bunch grass on hills, sometimes far from water.

Some visit NC Peruvian coast during May–Sept (5 Fjeldså, J., and N. Krabbe (1990). Birds of the High Andes: A Manual to the Birds of the Temperate Zone of the Andes and Patagonia, South America. Zoological Museum, University of Copenhagen and Apollo Books, Copenhagen and Svendborg, Denmark. Close ). Vagrants observed in N Peru (6 Chávez Villavicencio, C. (2007). Las aves del santuario de conservación regional manglares San Pedro de Vice, Secura, Perú. Cotinga. 27: 32–37. Close , 7 Rivas Mogollón, E.L., Pariapaza Liviapoma, E. and Nuñez Cortez, E.I. (2013). Aves del Humedal de Santa Julia, Piura - Perú. Bol. UNOP. 8(1): 10–20. Close ), with a recent record (Jan 2015) in the highlands of W Ecuador (8 Williams, R. (2016). Neotropical notebook. Neotropical Birding. 18: 45–52. Close ).

Diet unrecorded, but probably based on arthropods and other invertebrates. Usually feeds in flocks, often in fair numbers; mostly feeds by probing into mud in creeks and flooded areas .

Flight call a rapid series of short nasal quacks “kvek..kvek...kvek..”. On the ground, gives a more drawn-out “kwaaah” or “raaah” with longer pauses between notes.

Season variable: laying peaks in Apr–Jul, but also recorded in Dec–Mar in Peru, and Nov in Bolivia. Colonial. Nest a platform of dry vegetation, constructed in tall reeds c. 0·5–1 m above water level. Usually lays two eggs (1–2); chick has dark brown down.

Not globally threatened (Least Concern). The global population is estimated at 10,000–15,000 birds, but is thought likely to be declining due to habitat destruction. It is common in the uplands of Peru and in Bolivia. In Peru there were counts  in the late 1970s of 8000 birds at Lake Junín, and 1300 at L Arapa and wetland areas of Taraco. In Bolivia 105 birds were counted at L Alalay, Bolivia, and it is a common resident around L Titicaca. It is Red-listed in Chile, where it is classed as Vulnerable; until 1965 there were just two confirmed records of one and three birds, respectively, but sizeable flocks were recorded in 1970: 32 in marshes at Parinacota, Arica, and 40 near Isluga, Tarapacá. The isolated population in the altiplano of Jujuy, NW Argentina, is apparently not numerous.