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Ground roller

life science Maturity 7-9 Next article →

Ground rollers are a unique family of birds called Brachypteraciidae. They are non-migratory, meaning they do not travel to different lands each year. These birds are found only on the island of Madagascar. They belong to the larger order Coraciiformes. This order also includes the true rollers, found in the family Coraciidae. Ground rollers are most closely related to those true rollers. However, they have developed very different ways of living.

Short-legged Ground-roller, Masoala National Park, Madagascar
Short-legged Ground-roller, Masoala National Park, Madagascar

These birds have physical traits that help them live on the forest floor. They have a general build and size similar to crows. Unlike true rollers, ground rollers spend much more time on the ground. This terrestrial lifestyle is supported by their anatomy. They possess longer legs for walking and running. Their wings are shorter and more rounded than those of their relatives. They also have duller plumage, often featuring striped or flecked patterns. This makes them much more elusive and shy than true rollers.

Scaly Ground-Roller iNaturalist
Scaly Ground-Roller iNaturalist

Ground rollers have a very specific way of raising their young. They live and nest as solitary pairs. While true rollers rarely nest in ground holes, ground rollers prefer them. In fact, ground rollers excavate their own nesting holes in the earth. This digging behavior sets them apart from the Coraciidae family. Because they are so shy, seeing them in Malagasy forests is difficult. Often, the only way to know they are nearby is by hearing their hooting breeding call.

Atelornis pittoides -Zurich Zoologischer Garten-8a
Atelornis pittoides -Zurich Zoologischer Garten-8a

Scientists use several methods to understand the history of these birds. In 2001, researchers used mtDNA analyses to study their genetics. This type of analysis helps confirm the systematics, or the way groups are organized. These studies showed that the genus Geobiastes should be separate from Brachypteracias. This reversed a grouping that had been common since the 1960s. Researchers are waiting for more comprehensive reviews, perhaps using fossils, to finalize these relationships.

Long-tailed Ground-roller, Mangily, Madagascar 3
Long-tailed Ground-roller, Mangily, Madagascar 3

The fossil record also provides important clues about the past. In 2000, scientists described an extinct species called the Ampoza ground roller. This species, Brachypteracias langrandi, was identified from a single humerus, which is a bone in the wing. These remains were 2,000-year-old subfossils from the Holocene of Ampoza. Earlier, Eocene remains found in Europe were once thought to be ground rollers. However, researchers later recognized those fossils as quite distinct. Current evidence shows ground rollers have likely only ever lived in Madagascar.

Atelornis pittoides -Zurich Zoologischer Garten-8a
Atelornis pittoides -Zurich Zoologischer Garten-8a

There are currently five living species of ground rollers. These species are divided into four different genera. The Short-legged ground roller belongs to the genus Brachypteracias. The Scaly ground roller is part of the genus Geobiastes. The Long-tailed ground roller belongs to the genus Uratelornis. Finally, the genus Atelornis includes two species. These are the Pitta-like ground roller and the Rufous-headed ground roller. Each species plays a role in the ecosystem of Madagascar.

Scaly Ground-Roller iNaturalist
Scaly Ground-Roller iNaturalist

Understanding ground rollers helps scientists study the diversity of Madagascar. These birds are part of a complex web of life on the island. Their specific needs for forest habitats and ground nesting make them unique. By studying their biology and their history, we learn more about the order Coraciiformes. We also learn how different environments shape the bodies and behaviors of birds. The study of these elusive creatures continues to grow through new scientific research.

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🖼️ Images & Media (4)
File:Short-legged Ground-roller, Masoala National Park, Madagascar.jpg
Short-legged Ground-roller, Masoala...
File:Scaly Ground-Roller iNaturalist.jpg
Scaly Ground-Roller iNaturalist.jpg
File:Long-tailed Ground-roller, Mangily, Madagascar 3.jpg
Long-tailed Ground-roller, Mangily,...
File:Atelornis pittoides -Zurich Zoologischer Garten-8a.jpg
Atelornis pittoides -Zurich Zoologischer...
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