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Sunbittern

life science Maturity 5-7 Next article →

The sunbittern (Eurypyga helias) is a unique bird found in the tropical regions of the Americas. It is the only living member of its family, Eurypygidae, and its own genus, Eurypyga.

Eurypyga helias -Tulsa Zoo -USA-8a
Eurypyga helias -Tulsa Zoo -USA-8a

These birds live in humid Neotropical forests. They prefer areas with an open understorey. They are usually found near water sources like rivers, streams, ponds, or lagoons. The sunbittern is an important subject for scientists studying bird evolution and history.

One of the most striking features of the sunbittern is its wing display. While the bird has subdued colors like grey, brown, and black, its wings hold a secret. The remiges, or flight feathers, have vividly colored middle webs. When the bird spreads its wings, it reveals large eyespots made of red, yellow, and black.

Stavenn Eurypiga helias 00
Stavenn Eurypiga helias 00

Sunbitterns use these displays for two main reasons. First, they use them during courtship to communicate with other birds. Second, they use them as a threat display to startle potential predators. This sudden flash of "eyes" can give the bird time to escape.

Scientists categorize the sunbittern into three distinct subspecies based on their size and plumage. These subspecies are allopatric, meaning they live in different geographic areas. The Amazonian sunbittern (E. h. helias) lives east of the Andes in the Amazon basin and Pantanal. The northern sunbittern (E. h. major) ranges from southern Guatemala through Central America to western Ecuador.

Ma - Eurypyga helias - 1
Ma - Eurypyga helias - 1

Finally, the foothill sunbittern (E. h. meridionalis) lives along the East Andean slope in south-central Peru. These subspecies show physical differences, such as the color of their legs and bills.

Tracing the history of the sunbittern reveals a complex evolutionary story. It was once thought to belong to the order Gruiformes. However, molecular studies suggest it belongs to a different group. The sunbittern is most closely related to the kagu (Rhynochetos jubatus) of New Caledonia. Both birds belong to the clade Eurypygiformes. They also both possess powder down, which is a specialized type of feather. This connection suggests they may share a Gondwanan origin. This means their ancestors likely lived on the ancient supercontinent called Gondwana.

Fossil evidence provides even more clues about where these birds used to live. An indeterminate fossil of a eurypygid was found in the Green River Formation in Wyoming, USA. This specimen is a full skeleton and is the oldest known fossil of this group. Researchers have given it the unofficial name "Eoeurypyga olsoni" in some studies. This discovery is significant because it suggests the group once had a much more northern range.

Eurypyga helias - Karlsruhe Zoo
Eurypyga helias - Karlsruhe Zoo

This shows how animal habitats can change drastically over millions of years.

Sunbitterns are highly skilled hunters with a very diverse diet. They eat many types of invertebrates, including cockroaches, dragonflies, moths, and spiders. They also consume vertebrates like fish, tadpoles, eels, and lizards.

Eurypyga helias -Tulsa Zoo -USA-8a
Eurypyga helias -Tulsa Zoo -USA-8a

Remarkably, sunbitterns have shown a rare form of intelligence. In captive settings, they have been observed using bait to lure prey. This is a form of tool use. They are one of only 12 bird species known to use this specific fishing behavior.

The life cycle of the sunbittern is closely tied to the seasons. They begin nesting during the early wet season. Before nesting, they perform flight displays high in the forest canopy. They build open nests in trees and lay two eggs with blotched markings. The young are precocial, which means they are relatively mature and mobile when they hatch. However, they still remain in the nest for several weeks to grow and develop.

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🖼️ Images & Media (4)
File:Eurypyga helias -Tulsa Zoo -USA-8a.jpg
Eurypyga helias -Tulsa Zoo -USA-8a.jpg
File:Stavenn Eurypiga helias 00.jpg
Stavenn Eurypiga helias 00.jpg
File:Ma_-_Eurypyga_helias_-_1.jpg
Ma_-_Eurypyga_helias_-_1.jpg
File:Eurypyga helias - Karlsruhe Zoo.jpg
Eurypyga helias - Karlsruhe Zoo.jpg
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