Black-chested snake eagle

The black-chested snake eagle, also called the black-breasted snake eagle (Circaetus pectoralis), is a large bird that lives in African forests and grasslands. It belongs to the Accipitridae family, which includes many birds of prey like hawks and eagles.

This eagle looks similar to other snake eagles, and scientists used to think it was the same species as the short-toed and Beaudouin's snake eagles. These birds are closely related, but they have some differences that help scientists tell them apart.

Black-chested snake eagles are special because they are good at catching and eating snakes, which can be tricky for other birds. They play an important role in keeping the balance of nature by controlling snake populations.

Taxonomy

The black-chested snake eagle was once thought to be part of the short-toed snake eagle group. Some scientists believed they were the same species, while others saw differences in their looks and where they lived as reasons to treat them as separate species. Recent studies using DNA have shown that the black-chested snake eagle is actually closer in family to the brown snake eagle than to the short-toed snake eagle. This helps explain why it is now recognized as its own distinct species.

Identification

The black-chested snake eagle is known for its dark brown-black head and chest, which gives it its name. It looks different from the short-toed and Beaudouin's snake eagles because it has white feathers on its lower body, unlike the other two types. When it flies, you can see its dark head and chest against its white belly and wing underside, with just a few narrow black lines at the tips of the underwings. Both males and females look the same, but the female is larger. It can sometimes be mistaken for the martial eagle, but it is smaller, has a plain breast without spots, and has white underwings instead of brown-black. Its eye is bright yellow-orange, its bill is horn-coloured, and its legs are pale grey and not feathered below the thigh.

The bird makes a whistling sound that goes kwo kwo kwo kweeoo.

Distribution

The black-chested snake eagle lives in parts of Africa. You can find them in southern and East Africa, from Ethiopia and Sudan in the north down to South Africa in the south. They also live as far west as the southern Democratic Republic of the Congo and southeastern Gabon.

Some of these birds stay in the same place all year, especially in southern and East Africa. But in places like Sudan, they are only seen when they come to breed. In Ethiopia and the former Transvaal, they visit but don’t usually breed there. Even in areas where they normally stay, like Zimbabwe, some birds move around more during the dry winter months.

Habitat

The black-chested snake eagle lives in many different places, such as open woodlands, grasslands, and savannas. It can also be found in dry areas and near farms, often using electricity pylons or telephone poles. This bird usually lives alone, but sometimes groups of up to 200 come together when they are not breeding. It shares its home with another eagle called the brown snake eagle, and they can even nest close to each other without fighting.

Feeding Ecology

The black-chested snake eagle mostly eats snakes, especially venomous ones up to 80 cm long, but it will also eat lizards, insects, small mammals, and frogs. This bird hunts from a perch, hovers in the air, or searches the ground. It stalks its prey in the air and then slowly drops to the ground to catch it.

This species depends a lot on how many small mammals are available, with its numbers going up when there are more small mammals around, especially in Serengeti National Park. An old sample from Morogoro, collected in 1922, had rodent fur and a hissing sand snake in its stomach.

Reproduction

The black-chested snake eagle builds its nests in trees, often in flat-topped acacia trees, sometimes using other trees like pine. The nest is made of sticks and hidden among plants. The female lays one white egg and takes care of it alone for about 52 days, while the male brings her food. After the egg hatches, the baby bird stays in the nest for around three months. These birds can breed at any time of year, but they most often lay eggs during the dry winter months in places like South Africa, with different timing in other areas like Zambia and Zimbabwe.

Conservation

The black-chested snake eagle is considered safe by the IUCN and BirdLife International. Though found in many places, the number of these birds can change a lot, sometimes being very common and other times hard to find. Scientists think these changes might happen because some birds stay in one place while others move around, or because there isn’t always enough food.

Sometimes, these birds can get into trouble from human activities, such as getting caught in water, being hurt by accidents with electricity wires, or other dangers. However, these problems don’t seem to affect the bird’s numbers too much.