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Branta

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The genus *Branta* consists of a group of waterfowl known as black geese. These birds belong to the Anserinae subfamily, which includes true geese and swans.

The geese of Europe and Asia (Branta bernicla bernicla)
The geese of Europe and Asia (Branta bernicla bernicla)

They are distinct from other true geese due to specific physical traits. Most notably, they possess black or very dark grey legs and feet. They also feature black bills and large dark areas on their heads and necks. Many species also display white or ochre markings on these dark areas. These markings serve as important tools for scientists to identify different species.

Identifying a *Branta* species involves looking closely at specific color patterns. While most have white markings, the nēnē is a notable exception. The nēnē lives in the Hawaiian Islands and lacks white on its head or neck. It also has much less black coloration than its relatives. Because of these unique traits, it was once placed in a different genus called *Nesochen*.

The Birds of the Sandwich Islands (Bernicla sandvicensis)
The Birds of the Sandwich Islands (Bernicla sandvicensis)

Other geese, like the swan goose, may have black bills but possess reddish-orange legs. This difference in leg color helps researchers confirm that the swan goose is not a member of *Branta*. Most geese also share the trait of having white undertail and uppertail coverts.

These birds occupy diverse geographic ranges across the globe. Many species live in the northern coastal regions of the Palearctic. Others are found throughout North America.

Ornithologia Neerlandica (Branta canadensis)
Ornithologia Neerlandica (Branta canadensis)

During the winter, many of these birds migrate to more southerly coasts. Some, like the nēnē, remain in the Hawaiian Islands as resident birds. In New Zealand, a self-sustaining feral population exists. This population actually comes from introduced Canada geese.

The geese of Europe and Asia (Branta ruficollis)
The geese of Europe and Asia (Branta ruficollis)

In Eurasia, *Branta* species tend to stay near the coast. This differs from the genus *Anser*, or grey geese, which can live much further inland.

The scientific history of this genus began in 1769. An Austrian naturalist named Giovanni Antonio Scopoli introduced the name *Branta*. The name is a Latinized version of the Old Norse word *Brandgás*. This term translates to "burnt goose," referring to the dark colors of the birds.

The geese of Europe and Asia (Branta leucopsis)
The geese of Europe and Asia (Branta leucopsis)

Since then, scientists have worked to map their complex family trees. In 2016, a study by Ottenburghs and colleagues established the phylogenetic relationships between the species. This research helps us understand how different species evolved from common ancestors.

There are currently six living species within the *Branta* genus. While most are smaller than other geese, some large taxa exist. These large birds can rival the size of the swan goose or the black-necked swan.

The geese of Europe and Asia (Branta hutchinsii)
The geese of Europe and Asia (Branta hutchinsii)

The fossil record also provides a deep look into their past. Several fossil species have been described from different eras. These include *Branta woolfendeni* from the Late Miocene of Arizona and *Branta thessaliensis* from Greece. Other fossils, such as *Branta dickeyi*, date to the Late Pliocene and Late Pleistocene of the western United States.

Prehistoric history in the Hawaiian Islands reveals even more about these birds. Two extinct species once lived there, known from subfossil remains. One was the *Branta hylobadistes*, also called the wood-walking goose. The other was the giant Hawaii goose, or *Branta rhuax*.

The geese of Europe and Asia (Branta leucopsis)
The geese of Europe and Asia (Branta leucopsis)

The history of *B. rhuax* was once very confusing. Scientists originally studied a skeleton that had been damaged by a lava flow. In 1970, Lester Short proposed it might be related to shelducks. However, reexamination of the bones in 2013 confirmed it belonged to the *Branta* genus.

Understanding *Branta* helps scientists connect different parts of the natural world. Studying their fossils allows researchers to track how birds moved across land and sea over millions of years. The discovery of bones on Kauaʻi and Oʻahu suggests a complex history of waterfowl in the Pacific. Some remains even hint at the presence of gigantic waterfowl that are difficult to classify. By studying these birds, we learn how climate, geography, and even volcanic activity shape the life of a species.

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🖼️ Images & Media (6)
File:The geese of Europe and Asia (Branta bernicla bernicla).jpg
The geese of Europe and Asia (Branta...
File:The geese of Europe and Asia (Branta ruficollis).jpg
The geese of Europe and Asia (Branta...
File:The Birds of the Sandwich Islands (Bernicla sandvicensis).jpg
The Birds of the Sandwich Islands...
File:Ornithologia Neerlandica (Branta canadensis).png
Ornithologia Neerlandica (Branta canadensis).png
File:The geese of Europe and Asia (Branta leucopsis).jpg
The geese of Europe and Asia (Branta...
File:The geese of Europe and Asia (Branta hutchinsii).jpg
The geese of Europe and Asia (Branta...
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