Buff-necked Ibis

About

The Buff-necked Ibis, locally known as Curicaca, is a large, striking ibis species found across a wide range of open habitats in South America. It is characterized by its long, decurved bill, buff-colored neck, and iridescent dark plumage. These birds are often seen foraging in wetlands, grasslands, and agricultural fields, typically in small groups.

Size & lifespan

Length

71-79 cm (28-31 in)

Wingspan

120-130 cm (47-51 in)

Weight

1.2-1.7 kg (2.6-3.7 lbs)

Lifespan

Up to 15-20 years in the wild

Diet

Omnivore, primarily insectivore and carnivore

Physical characteristics

Plumage

Adults have a distinctive buff-colored neck and head, contrasting with a dark, iridescent green-black body. The back and wings are dark, often appearing glossy green or purple in good light. A broad white band separates the buff neck from the dark breast. The underparts are dark. The flight feathers are blackish. There is a prominent crest of shaggy feathers on the nape.

Beak shape

Long, slender, and strongly decurved (downward-curving) bill, dark grey to blackish.

Eye color

Reddish-brown to dark brown.

Leg color

Dull reddish-orange to dark greyish-red.

Distinguishing features

The combination of the buff neck, dark body, and long decurved bill is unique among ibises in its range. The shaggy crest on the nape is also a good field mark.

Juvenile appearance

Juveniles resemble adults but have duller plumage, with less distinct buff coloration on the neck and head, and less iridescence on the body. Their crest is also less developed.

Seasonal changes

No significant seasonal plumage changes. Breeding plumage is essentially the same as non-breeding plumage, though colors may appear more vibrant during the breeding season due to better feather condition.

Sexual dimorphism

Males and females are monomorphic in plumage, though males may be slightly larger on average.

How to identify

1. 1

   Buff Neck and Head

   Look for the prominent, warm buff coloration on the entire neck and head, which is a key distinguishing feature from other ibises.

2. 2

   Dark Body and White Band

   Observe the dark, iridescent green-black body plumage, separated from the buff neck by a distinct broad white band across the upper breast.

3. 3

   Decurved Bill

   Note the long, slender, and strongly downward-curving dark bill, characteristic of ibises.

4. 4

   Shaggy Crest

   Look for the shaggy, somewhat disheveled crest of feathers on the nape, especially visible when the bird is alert.

5. 5

   Vocalization

   Listen for its loud, raucous, and far-carrying 'curi-curi-ca' calls, which are highly distinctive and often given in flight.

6. 6

   Habitat

   Scan open, wet areas such as flooded fields, pastures, and marsh edges, where they frequently forage.

Habitat & range

Biomes

Grasslands, savannas, wetlands, agricultural fields, open woodlands, marshes, and riverbanks.

Geographic range

South America, from northern Colombia and Venezuela south through Brazil, Bolivia, Paraguay, Uruguay, and northern Argentina. Also found in parts of Guyana, Suriname, and French Guiana.

Elevation range

Primarily lowlands, up to approximately 1,000 meters (3,300 feet) above sea level, occasionally higher in some Andean valleys.

Preferred environments

Prefers open, wet areas such as flooded fields, pastures, marshes, and the edges of ponds and rivers. They adapt well to human-modified landscapes, including rice paddies and cattle ranches.

Behavior

Activity time

Diurnal, actively foraging during daylight hours.

Feeding habits

Forages by probing its long, decurved bill into soft ground, mud, or shallow water to extract invertebrates. Diet includes insects (beetles, grasshoppers, crickets), larvae, worms, snails, small crustaceans, frogs, lizards, and occasionally small snakes or fish. They often follow cattle, feeding on insects disturbed by the livestock.

Social behavior

Typically found in small to medium-sized flocks, especially when foraging or roosting. They can form larger aggregations at favored feeding sites or communal roosts. They are generally gregarious but can be seen singly or in pairs.

Flight pattern

Strong, direct flight with powerful, steady wing beats. They often soar on thermals, especially when moving between feeding grounds. In flight, the long neck and legs are extended, and the dark body contrasts with the buff neck.

Migration pattern

Mostly resident throughout its range, but some populations may undertake local or regional movements in response to rainfall patterns and food availability, particularly in drier regions.

Territoriality

While generally gregarious, breeding pairs will defend a small territory around their nest site.

Breeding & reproduction

Breeding season

Varies geographically, generally coinciding with the rainy season or periods of increased food availability. In some regions, it can be from July to October, while in others, it might be from September to December or even year-round.

Nesting habits

Nests are typically large, bulky platforms made of sticks and twigs, lined with softer vegetation. They are usually built in trees (often tall, isolated trees) or sometimes on cliffs, often near water. They may nest colonially with other ibises or storks, or in small, loose groups.

Clutch size

2-4 eggs, most commonly 3.

Egg description

Typically 2-4 eggs, pale greenish-blue or bluish-white, often unmarked or with faint brownish spots.

Incubation period

Approximately 28-30 days.

Fledging period

Chicks fledge (leave the nest) around 40-50 days after hatching, but remain dependent on parents for some time thereafter.

Parental care

Both parents participate in nest building, incubation, and feeding of the young. They bring food to the nestlings by regurgitation.

Where to find

Field tips

1. Look for foraging groups. Buff-necked Ibises often forage in small groups, making them easier to spot than solitary birds. Look for them probing the ground with their bills.
2. Listen for calls. Their loud, distinctive calls are often the first indication of their presence, especially when they are flying overhead or disturbed.
3. Scan open areas. Focus your search on open, wet habitats. They are less likely to be found in dense forests.
4. Check near livestock. They frequently associate with cattle, feeding on insects stirred up by the animals. Look for them in pastures with grazing livestock.
5. Observe flight patterns. When in flight, their extended neck and legs, combined with their dark body and buff neck, are good identification clues.

Similar species

Quick facts

Diet:

Insects, worms, small vertebrates

Habitat:

Wetlands, grasslands, agricultural fields

Social Behavior:

Gregarious, often in small flocks

Vocalization:

Loud, raucous 'curi-curi-ca' calls

Conservation Status:

Least Concern

Fun facts

• The local name 'Curicaca' is an onomatopoeia, directly mimicking its distinctive call.
• They are highly adaptable and have successfully colonized human-modified landscapes, such as cattle ranches and rice fields.
• Like many ibises, they often roost communally in tall trees, sometimes with other waterbird species.
• Their long, decurved bill is perfectly adapted for probing into soft substrates to find hidden prey.

Scientific classification

Kingdom

Animalia

Phylum

Chordata

Class

Aves

Order

Pelecaniformes

Family

Threskiornithidae

Genus

Theristicus

Species

Theristicus caudatus

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