Ibises are wading birds of the Threskiornithidae family. They fall under the order Pelicaniiformes, together with spoonbills. Waders are a diverse group of birds that feed by wading through shallow waters. To facilitate this, they typically have long legs. Many waders also have long, flexible necks and long bills for foraging in water or spearing prey. Birds in this group also include herons, storks, cranes, and flamingos.
Ibises and Spoonbills are closely related. Their most striking difference is in bill shape, with the Ibises having curved bills and the Spoonbills having straight bills that are broad at the end. Ibises use their bills to probe in mud, while Spoonbills move their side to side in the water to catch prey. Dietary items include crustaceans, mollusks, fish, insects, amphibians, reptiles, and even small mammals and carrion. At night they roost in trees that are near and often overhanging water.
1. Genus Bostrychia
1.1. Hadeda Ibis, Bostrychia hagedash
Description: The Hadeda Ibis has gray and partially brown plumage with iridescent purple and green. It has white cheek stripes, a white neck and breast, and blackish legs. Its bill is grayish with red near the base of the upper bill.
Range: Sub-Saharan Africa.
Habitat: Savanna, grasslands, wetlands, and suburban areas. They are common in parks, gardens, and cemeteries.
Conservation status: Least concern.
Similar species:
- Wattled Ibis – The hadeda has white cheek stripes and the wattled ibis has a brown head and wattles.
- White Ibis (juveniles) – The white ibis is found in the USA.
1.2. Olive Ibis, Bostrychia olivacea
Description: A small dusky ibis with iridescent green in its body plumage. It has a gray-brown head and dark blue tail coverts.
Range: Tropical parts of Africa.
Habitat: Dense forests.
Conservation status: Least concern.
1.3. São Tomé Ibis, Bostrychia bocagei
Description: The São Tomé Ibis has a slightly bronzed mantle and wing-coverts, a dull olive head, and blackish around the eyes.
Range: São Tomé off the western coast of central Africa.
Habitat: Primary forests.
Conservation status: The São Tomé ibis is critically endangered, mainly due to habitat loss and introduced species.
1.4. Spot-Breasted Ibis, Bostrychia rara
Description: The spot-breasted Ibis has a buff-colored spotted neck and breast.
Range: Tropical parts of Africa.
Habitat: Forests and swamps.
Conservation status: Although it is classified as least concern. The spot-breasted ibis is a rare bird with few confirmed sightings.
1.5. Wattled Ibis, Bostrychia carunculate
Description: The Wattled Ibis has mainly brown plumage, white shoulder patches, and a thin wattle attached to the base of the bill. It is similar to the hadeda ibis but the latter has white cheek stripes and no wattles and the wattled Ibis has a brown head.
Range: Ethiopia and Eritrea.
Habitat: Rocky cliffs, open country, farmlands, forests, parks, and gardens.
Conservation status: Least concern.
2. Genus Cercibis
There is only one species in this genus.
2.1. Sharp-Tailed Ibis, Cercibis oxycerca
Description: The sharp-tailed Ibis has an elongated body shape, a glossy black plumage, and short red wattles.
Range: Northern South America.
Habitat: Wet savannah, riverbanks, grasslands, and gallery forests.
Conservation status: Least concern.
3. Genus Eudocimus
3.1. Scarlet Ibis, Eudocimus ruber
Description: The scarlet ibis has bright scarlet-red plumage with black wingtips, a pinkish-red bill and legs, and dark eyes.
Range: They are native to South America and the Caribbean. Introduced populations have established in North America by birds escaping captivity.
Habitat: Wetlands, marshes, swamps, rainforests, tropical grasslands, mudflats, and coastal environments.
Conservation status: Least concern.
3.4. White Ibis (American White Ibis), Eudocimus albus
Description: The White Ibis has mainly white plumage with black-tipped wings.
Range: Southern USA to South America and the Caribbean.
Habitat: Fresh and saltwater marshes, wetlands, mangrove swamps, mudflats ponds, and flooded fields.
Conservation status: Least concern.
Similar species:
- Australian White Ibis; Black-Headed Ibis – Range does not overlap.
- Limpkin – The juvenile white ibis has a white belly, whereas the limpkin has a dark belly.
- Scarlet Ibis (juveniles) – White ibises occur in the USA.
4. Genus Geronticus
The bald ibises have bald heads which gives them a vulture-like appearance. They also differ from other ibises by breeding on cliffs rather than trees and preferring arid locations to wetlands. Unlike other ibises, they are not wading birds.
4.1. Northern Bald Ibis, (Waldrapp), Geronticus eremita
Description: The northern bald Ibis has glossy black plumage, a bald red crown and face, and a curved red bill.
Range: Morocco and possibly parts of the Middle East. It is extinct in most of its former range.
Habitat: Coastal, dry, or semi-desert environments. They nest along cliff ledges.
Conservation status: It is critically endangered a population of about 500 birds due to human disturbance and loss of habitat.
4.2. Southern Bald Ibis, Geronticus calvus
Description: The southern bald ibis has glossy black plumage, a bald red crown and face, and a curved red bill.
Range: Southern Africa.
Habitat: Mountainous grasslands. They nest along cliff ledges.
Conservation status: The southern bald ibis is classified as vulnerable due to human disturbance and habitat destruction.
5. Genus Lophotibis
There is only one species in this genus.
5.1. Madagascar Crested Ibis, Lophotibis cristata
Description: The Madagascar crested ibis has mostly brown plumage, with a glossy greenish-blue head, red orbital skin, red legs, a yellow bill, and white wings.
Range: Madagascar.
Habitat: High altitude forests and woodlands.
Conservation status: The Madagascar crested ibis is classified as near-threatened due to unsustainable hunting and habitat loss.
6. Genus Mesembrinibis
There is only one species in this genus.
6.1. Green Ibis, Mesembrinibis cayennensis
Description: The green ibis has mainly green plumage, a pale green bill and legs, and gray facial skin patches.
Range: Central and South America.
Habitat: Forest wetlands, swamps, and the edges of rivers and lakes.
Conservation status: Least concern.
7. Genus Nipponia
7.1. Crested Ibis, Nipponia nippon
Description: The crested Ibis has white plumage, with red bare skin on head.
Range: A small population occurs in Shaanxi, Japan. They are extinct in most parts of their former range. They are now mainly found in captive environments in China, South Korea, and Japan.
Habitat: Forests, wet meadows, rice paddies, and river edges.
Conservation status: The crested ibis is endangered due to habitat loss, limited food resources, indiscriminate persecution, and the challenges of a limited range.
8. Genus Phimosus
There is only one species in this genus.
8.1. Bare-Faced Ibis, Phimosus infuscatus
Description: The bare-faced ibis has a dark brown to black plumage with a tinge of iridescent blue-green, a bare face, and a long pinkish-red bill.
Range: South America.
Habitat: Savannah, wet meadows, rice paddies, savannas, swamps, marshes, and other wetland environments.
Conservation status: Least concern.
9. Genus Plegadis
The Plegadis genus is probably most closely related to the Eudocimus genus. Eudocimus is the older lineage.
9.1. Giant Ibis, Pseudibis gigantea
Description: The largest of the ibises. It has grayish-brown plumage, a bald grayish head with dark stripes across the back, a yellowish-brown bill, orange legs, and dark red eyes.
Range: Cambodia, Laos, and Vietnam. It has disappeared from most of its former range.
Habitat: Lowland marshes, swamps, flooded plains, wet meadows, forests, river edges, and lakesides.
Conservation status: The giant ibis is critically endangered due to habitat destruction and human disturbance.
9.2. Glossy Ibis, Plegadis falcinellus
Description: The glossy Ibis has glossy reddish-brown plumage, green wings, a brownish bill, dark facial skin, and reddish-brown legs. Nonbreeding birds and juveniles are duller.
Range: The Americas, Europe, Asia, Africa, and Australia.
Habitat: Densely vegetated wetlands, swamps, and marshes near lakes and rivers. They also occur around lagoons, floodplains, wet meadows, and irrigated farmland.
Conservation status: Least concern.
Similar species:
- Limpkin – The glossy ibis is darker and its bill is more curved than the limpkin’s.
- White-Faced Ibis – The nonbreeding lossy ibis and white-faced ibis are very similar. The glossy ibis has dark eyes, whereas the white-faced ibis has reddish eyes. Also, the breeding white-faced Ibis has a white border around its face.
9.3. Puna Ibis, Plegadis ridgwayi
Description: A dark ibis with a chestnut-colored head and neck, and reddish facial skin which is brighter during the breeding season. Nonbreeding birds and juveniles have white streaks on the head and neck.
Range: Argentina, Bolivia, Chile, and Peru.
Habitat: Swamps, marshes, and lakes.
Conservation status: Least concern.
9.4. White-Faced Ibis, Plegadis chihi
Description: The white-faced ibis has a bare pink face bordered by white feathers. It has a gray bill, red legs, and reddish eyes. Nonbreeding birds lack the white coloration on the face. It is similar to the glossy ibis but the white-faced ibis has reddish eyes and the glossy ibis does not have a white face.
Range: Western USA to South America.
Habitat: Shallow wetlands and irrigated crop fields.
Conservation status: Least concern.
9.5. White-Shouldered Ibis, Pseudibis davisoni
Description: A large ibis with an overall dark plumage with a white neck ring and pale nape and shoulder patches (mainly visible in flight).
Range: Southwestern China to Myanmar, peninsular Thailand, and Indochina.
Habitat: Lowland forests, rice fields, shrubby grasslands, river edges, and lakesides.
Conservation status: The small population is critically endangered due to habitat loss.
10. Genus Pseudibis
10.1. Red-Naped Ibis (Black Ibis), Pseudibis papillosa
Description: The red-naped Ibis has a dark black and brown plumage. It has a crimson patch on the head and a white patch near the shoulder.
Range: Indian subcontinent.
Habitat: Marshes, lakes, riverbeds, and irrigated agricultural fields.
Conservation status: Least concern.
11. Genus Theristicus
Found in open, grassy habitats in South America. All have a long, decurved dark bill, relatively short reddish legs that do not extend beyond the tail in flight, at least the back is gray.
11.1. Black-Faced Ibis, Theristicus melanopis
Description: The black-faced ibis has a striking plumage in contrasting shades of gray, buff, brown, and white with a prominent dark band across the lower breast. It has dark eyes, a blackish bill, and red legs. It is similar to the buff-necked ibis but the latter has large, white wing patches.
Range: The southern parts of South America, further south than the similar buff-necked ibis.
Habitat: Grasslands and open forests.
Conservation status: Least concern.
11.2. Buff-Necked Ibis (White-Throated Ibis), Theristicus caudatus
Description: The buff-necked Ibis has a striking plumage in contrasting shades of gray, buff, black, and cinnamon-brown. It has a blackish bill, dark orbital skin, and red legs. It is similar to the black-faced ibis but it has large white wing patches and the black-faced Ibis does not.
Range: South America.
Habitat: Savanna, grasslands, and wetlands.
Conservation status: Least concern.
11.3. Plumbeous Ibis, Theristicus caerulescens
Description: The plumbeous ibis has mainly gray plumage with a white forehead and elongated plumes on the neck. It has orange eyes and red legs.
Range: South America.
Habitat: Lowland marshes, swamps, flooded pastures, lagoons, shallow lakes, ponds, and other wetland environments.
Conservation status: Least concern.
12. Genus Threskiornis
Birds of this genus inhabit the warmer parts of southern Asia, Australasiam and sub-Saharan Africa.
12.1. Australian White Ibis, Threskiornis molucca
Description: The Australian white ibis has mainly white plumage, with a black head, bill, tail, and legs. It is similar to the black-headed ibis but their ranges do not overlap.
Range: Australia.
Habitat: Wetlands and grasslands. In some parts of their range, they occur in urban areas where they are found in parks, gardens, and even garbage dumps.
Conservation status: Least concern.
12.2. Black-Headed Ibis, Threskiornis melanocephalus
Description: The black-headed ibis has mainly white plumage, with a black head, bill, tail, and legs. It is similar to the Australian white Ibis, but their ranges do not overlap.
Range: Asia and Southeast Asia
Habitat: Salt and freshwater marshes, lakes, ponds, rice paddies, agricultural land, riversides, and urban areas where they frequent garbage dumps.
Conservation status: The black-headed ibis is classified as near-threatened, possibly due to habitat loss.
12.3. Sacred Ibis, Threskiornis aethiopicus
Description: The sacred Ibis has mainly white plumage, with a black head, bill, tail, and legs.
Range: They are native to Africa, but were also introduced to Europe.
Habitat: Fresh and saltwater wetlands, mudflats, wet pastures, agricultural fields, and garbage dumps.
Conservation status: Least concern.
12.4. Straw-Necked Ibis, Threskiornis spinicollis
Description: The straw-necked ibis is mostly black has with a white neck, belly, and under-tail.
Range: Australia, New Guinea, Indonesia, and Tasmania. Vagrants occur in New Zealand and surrounding Islands.
Habitat: Wetlands, grasslands, agricultural fields, swamps, and lagoons.
Conservation status: Least concern.
