Glossy Ibis

About

The Glossy Ibis is a medium-sized wading bird characterized by its rich, iridescent dark plumage, long decurved bill, and long legs. It is the most widespread ibis species globally, found in warm regions across Europe, Asia, Africa, Australia, and the Americas. It typically inhabits wetlands, feeding on invertebrates and small vertebrates.

Size & lifespan

Length

48-66 cm (19-26 in)

Wingspan

80-105 cm (31-41 in)

Weight

485-970 g (1.07-2.14 lbs)

Lifespan

Up to 20 years in the wild

Diet

Carnivore (primarily invertebrates and small vertebrates)

Physical characteristics

Plumage

Adult breeding plumage is a striking deep chestnut-maroon on the body, with iridescent bronze-green and purplish gloss on the wings, back, and tail. The head and neck are also chestnut. Non-breeding adults are duller, with a streaky brown head and neck, and less vibrant body plumage. Juveniles are duller still, mostly dark brown with a duller green gloss and a pale, streaky head and neck.

Beak shape

Long, slender, strongly decurved (downcurved) bill, dark olive-brown to blackish. In breeding adults, a pale blue-grey line runs from the base of the bill to the eye, bordered by a darker line below.

Eye color

Dark brown, surrounded by a narrow, pale blue-grey orbital ring in breeding adults.

Leg color

Dark olive-green to blackish, becoming reddish-brown during the breeding season.

Distinguishing features

Its unique combination of dark, iridescent plumage, long decurved bill, and dark legs distinguishes it from most other wading birds. The pale facial line in breeding adults is a key field mark.

Juvenile appearance

Juveniles are duller than adults, with a dark brown body and a less pronounced iridescent sheen. Their head and neck are streaky brown, lacking the rich chestnut of adults, and the facial skin is duller.

Seasonal changes

Breeding adults exhibit richer chestnut plumage and more vibrant iridescent gloss, along with the distinctive pale blue-grey facial line. Non-breeding adults and juveniles are duller, with less distinct facial markings.

Sexual dimorphism

Males and females are generally similar in plumage, though males tend to be slightly larger.

How to identify

1. 1

   Overall Plumage

   Look for the dark, iridescent plumage. In good light, the rich chestnut body and bronze-green/purplish wings are striking. In poor light, it may appear uniformly dark.

2. 2

   Bill Shape

   The long, slender, and strongly decurved (downcurved) bill is a primary identification feature, used for probing in mud.

3. 3

   Facial Markings (Breeding Adults)

   Observe the pale blue-grey line running from the base of the bill to the eye, bordered by a darker line below. This is absent in non-breeding adults and juveniles.

4. 4

   Legs

   Long, dark legs, which become reddish-brown during the breeding season. They trail behind the body in flight.

5. 5

   Flight Pattern

   Watch for strong, direct flight with rapid wing beats, often in V-formations or diagonal lines, with neck extended and legs trailing.

Habitat & range

Biomes

Wetlands, marshes, swamps, shallow lakes, flooded fields, estuaries, and coastal lagoons.

Geographic range

Cosmopolitan distribution, found in scattered populations across Europe, Asia, Africa, Australia, and the Americas (including the Caribbean and parts of the southeastern United States).

Elevation range

Primarily lowlands, typically from sea level up to a few hundred meters.

Preferred environments

Shallow freshwater or brackish wetlands with emergent vegetation, muddy edges, and open water for foraging. They prefer areas with dense reeds or trees for nesting and roosting.

Behavior

Activity time

Diurnal, primarily active during daylight hours for foraging and other activities.

Feeding habits

Forages by probing its long, decurved bill into soft mud or shallow water to find invertebrates such as insects, crustaceans, and worms. It also takes small fish, amphibians, and occasionally seeds. Often forages in groups, walking slowly and methodically.

Social behavior

Highly gregarious, especially outside the breeding season. They often form large flocks for foraging, roosting, and migration. Breeds colonially, often with other wading bird species.

Flight pattern

Strong, direct flight with rapid wing beats, often in V-formations or diagonal lines, especially during migration. Legs trail behind the body, and the neck is extended.

Migration pattern

Many populations are migratory, moving from temperate breeding grounds to warmer wintering areas. European and Asian populations migrate to Africa and South Asia. North American populations are largely resident in the southeast but may undertake local movements. Australian populations are nomadic.

Territoriality

Generally not territorial outside the immediate nest site within a colony. Foraging areas are typically shared.

Breeding & reproduction

Breeding season

Varies geographically: March-July in the Northern Hemisphere, August-December in the Southern Hemisphere, and year-round in tropical regions.

Nesting habits

Nests colonially, often in mixed-species colonies with other ibises, herons, and spoonbills. Nests are typically platforms of sticks, reeds, or other vegetation, built in dense emergent vegetation (reeds, cattails) or low trees/shrubs over water.

Clutch size

2-5 eggs

Egg description

2-5 (typically 3-4) elliptical eggs, pale turquoise-blue to greenish-blue, unmarked. They become duller and stained during incubation.

Incubation period

20-23 days

Fledging period

28-35 days, though young may leave the nest and clamber in surrounding vegetation before they can fly.

Parental care

Both parents share incubation duties and care for the young. Chicks are altricial (helpless at hatching) and are fed by regurgitation.

Where to find

Field tips

1. Look for groups. Glossy Ibises are often found in flocks, sometimes mixed with other wading birds like herons or spoonbills. Scan large areas of wetlands.
2. Observe feeding behavior. Watch for their characteristic probing action with their long, decurved bills in shallow water or mud. This behavior is distinctive.
3. Check lighting conditions. The iridescent plumage is best seen in good light. In overcast conditions, they may appear uniformly dark, making identification harder without other features.
4. Listen for calls. While not highly vocal, their guttural calls can sometimes draw attention, especially in flight or within a colony.

Similar species

Quick facts

Global Distribution:

Most widespread ibis species

Bill Shape:

Distinctively decurved

Plumage Iridescence:

Bronze-green and purplish gloss

Social Behavior:

Highly gregarious, colonial breeder

Diet:

Invertebrates and small vertebrates

Fun facts

• The Glossy Ibis is one of the most widely distributed wading birds in the world, found on every continent except Antarctica.
• Despite its name, the 'glossy' iridescence is only visible in good light; otherwise, the bird appears dark brown or black.
• They are excellent fliers and can undertake long migratory journeys, often flying in characteristic V-formations.
• Fossil evidence suggests that the Glossy Ibis has existed for millions of years, with fossils found dating back to the Miocene epoch.

Scientific classification

Kingdom

Animalia

Phylum

Chordata

Class

Aves

Order

Pelecaniformes

Family

Threskiornithidae

Genus

Plegadis

Species

Plegadis falcinellus

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