The ibis is a common sight in Australia today, easily recognized by its distinctive curved beak and straw-like plumage. But these birds were not always a fixture of the Australian landscape. Ibises are native to Africa, Europe, Asia and the Middle East. So how and when did they make their way down under?
In this article, we will explore the history of ibises in Australia. We will look at the different species found here, how they arrived, and when the first records of ibises inhabiting Australia appear. Understanding the origin story of the Australian ibis gives us insight into avian ecology, migration patterns, and the impacts of human movement on species distribution.
Ibis Species in Australia
There are four species of ibis that now reside in Australia:
- The Australian white ibis
- The straw-necked ibis
- The glossy ibis
- The sacred ibis
By far the most ubiquitous is the Australian white ibis. With its distinctive black head and white body plumage, this is the ibis most people picture when thinking of an Australian ibis.
The straw-necked ibis can be distinguished by the straw-like feathers on its neck. The glossy ibis has a darker plumage that shines purple and green in the light. The sacred ibis is an all-white ibis venerated in ancient Egypt.
Australian White Ibis
The Australian white ibis (Threskiornis moluccus) is found throughout much of Australia in both urban and rural wetland environments. It has a predominantly white plumage with black wings, a black head and neck, and that signature downward-curving beak.
Australian white ibises breed in large colonies near water sources. Their nests are platform-shaped structures made of sticks and lined with wetland vegetation. Female ibises lay 2-3 eggs that hatch after 21 days.
These opportunistic feeders consume a wide variety of prey including insects, small reptiles and amphibians, crabs, fish and frogs. They also forage for food scraps in urban areas like dumps, parks and schoolyards. This has led to their colloquial name of “bin chicken.”
Straw-necked Ibis
The straw-necked ibis (Threskiornis spinicollis) can be found across Australia, New Guinea, and parts of Indonesia. Identifiable by its distinctive straw-like feathers on the neck, this dark ibis has an iridescent plumage that appears purple-bronze in sunlight.
Straw-necked ibises inhabit freshwater wetlands and build platform nests in trees near water. They feed on insects, crustaceans, mollusks, frogs, fish and some plant material by probing in mud with their long beaks.
Glossy Ibis
The glossy ibis (Plegadis falcinellus) has a wide global range through Africa, Europe, Asia, and Australia. In Australia, it occupies freshwater and saline wetlands across the north and east coasts.
This dark ibis has a reddish-brown body, dark green wings, and an iridescent purplish-bronze neck and head that shines in the light. Glossy ibises wade through shallow waters probing for prey like crabs, fish, frogs and aquatic invertebrates.
Sacred Ibis
The sacred ibis (Threskiornis aethiopicus) is native to sub-Saharan Africa but has established feral populations in Europe, the Middle East, and Australia. In Australia, they are found in northern and eastern regions including Queensland, the Northern Territory and New South Wales.
Sacred ibises are almost all white with black wing tips. During breeding seasons they develop a buff-colored plume on the rump. In ancient Egypt, they were revered and associated with the god Thoth. Sacred ibises forage in wetlands eating invertebrates, small vertebrates and plant material.
Arrival of Ibises in Australia
Ibises are not native to Australia. Species like the Australian white ibis descended from ibises that flew from nearby islands like New Guinea and Indonesia. Other ibis species were introduced more recently to Australia.
Natural Range Expansion
The Australian white ibis likely descended from populations in New Guinea that naturally expanded their range into Australia thousands of years ago. Fossil evidence and Aboriginal rock paintings depict ibises inhabiting Australia prior to European colonization.
Experts believe Australian white ibises flew south from New Guinea and Indonesia to Australia during periodic extreme weather events like cyclones that provided favorable winds for the journey. Range expansion was also facilitated by lower sea levels during past ice ages exposing land bridges.
Introduction from Africa and Asia
The glossy ibis and sacred ibis were introduced more recently to Australia through human intervention. Populations of these species established from escaped zoo and aviary birds.
The first recording of glossy ibises in Australia was in 1948 in Townsville. In the 1960s, sacred ibises escaped from the Perth Zoo and Taronga Zoo to establish feral colonies. Straw-necked ibises may have also been introduced from Asia in the late 19th century.
Significant Events in Australia Ibis History
Here are some notable events marking the history of ibises inhabiting Australia:
Prehistoric Range Expansion
- 9000 BCE – Skeletal remains indicate ibises inhabited northern Australia during the early Holocene period.
- 3000 BCE – Aboriginal rock paintings depict ibises in Arnhem Land providing evidence of long-term occupation.
European Colonization
- 1770 – Captain Cook’s naturalist first describes the “New Holland Ibis” after sighting the birds along Australia’s east coast.
- 1789 – With the First Fleet, British sailors and colonists provide the first written records of frequent sightings of Australian white ibises.
Population Changes
- 1900s – Habitat loss leads to declining ibis populations. Ibises are shot by farmers for damaging crops.
- 1960s – Legal protection helps ibis numbers recover aided by adaptation to urban habitats.
- 1970s – Glossy ibis populations boom with more than 1000 breeding pairs across northern Australia.
Urban Colonization
- 1980s – Australian white ibises increasingly nest and forage in urban areas rather than just wetlands.
- 1990s – Large colonies take up residence in urban parks like Sydney’s Centennial Parklands.
- 2000s – Ibises become ubiquitous city dwellers earning nicknames like “bin chickens.”
Reasons for Ibis Success in Australia
A few key factors have allowed ibis populations to thrive on the Australian continent.
Adaptability
Ibises exhibit great adaptability to new environments, especially the Australian white ibis. As wetlands were altered and urban settlements expanded, ibises shifted their foraging and nesting behaviors to exploit these human-created habitats.
Generalist Feeders
Their varied diet of invertebrates, fish, amphibians, reptiles and plant material allows ibises to inhabit diverse freshwater and terrestrial habitats. As generalist feeders, they easily exploit many urban food sources.
Lack of Competition
Australia historically lacked biodiversity in bird species compared to older continents. With few avian competitors, the ibis’ generalized niche allowed it to successfully spread across Australia.
Climate
The Australian climate of seasonal rainfall producing temporary wetlands suits the ibis’ feeding behaviors. Their movement follows the boom and bust cycle of food availability in these ephemeral habitats.
Nesting Colonies
Ibises nest communally in large colonies providing safety in numbers from potential predators. These colonies act as focal points supporting expanding regional populations.
Legal Protection
Legal protections were introduced in the 1900s after significant hunting and habitat destruction caused declines. Ibis numbers rebounded with reduced persecution and active conservation efforts.
Urban Coexistence with Ibises
The close coexistence of ibises and humans in urban areas has produced some tensions:
Damage to Property
Ibis colonies can damage trees and infrastructure with their large nests and acidic droppings. Roosting birds cause unsightly mess and can spread disease.
Aggressive Foraging
Ibises scavenging in bins and dumps has led to conflicts with humans. Their boldness and sheer numbers can deter human usage of public spaces.
Noise
Their loud calls and squabbling, especially during breeding season, disturbs nearby human residents and businesses.
Health Risks
Large flocks increase exposure to bacterial diseases like salmonellosis that ibises can transmit to people and pets.
Solutions
Cities aim to find a balanced coexistence through actions like:
– Relocating nests away from sensitive infrastructure
– Modifying bins to deter foraging
– Culling programs in areas with highly problematic flocks
– Public education on hygienic practices
– Long-term planning of wetland conservation provide alternative habitats
Conclusion
From prehistoric wanderers to modern city dwellers, the adaptation of the ibis to Australian conditions has been a remarkable success story. Insights from the ibis experience reveal important principles of how invasive species can thrive in new environments. As human settlements continue to expand into wild areas, a thoughtful coexistence with nature is needed. The ibis will likely remain a ubiquitous fixture in both our swamps and suburbs for the foreseeable future.
