Serra antwren facts for kids
Quick facts for kids Serra antwren |
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| Male F. s. littoralis | |
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| Female F. s. littoralis | |
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Formicivora
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| Species: |
serrana
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The serra antwren (Formicivora serrana) is a small bird that eats insects. It belongs to a group of birds called "typical antbirds". These birds are found only in southeastern Brazil, which means they are endemic to that area.
Contents
What is a Serra Antwren?
Different Types of Serra Antwrens
The serra antwren has three main types, or subspecies, that scientists recognize around the world:
- F. s. serrana (Hellmayr, 1929)
- F. s. interposita Gonzaga & Pacheco, 1990
- F. s. littoralis Gonzaga & Pacheco, 1990
For a while, one of these types, F. s. littoralis, was thought to be a completely separate species. But after more studies, scientists found that its calls were very similar to the other two types. Its looks were also only slightly different. Because of this, it was put back as a subspecies of the serra antwren.
How Big Are Serra Antwrens?
Serra antwrens are small birds. They are about 12 to 14 centimeters (5 to 5.5 inches) long. They weigh between 10 and 13 grams (about 0.35 to 0.46 ounces). That's about as much as a few paper clips!
What Do Serra Antwrens Look Like?
Antwrens in the Formicivora group have tails that are quite long. Male antwrens in this group are special because their bellies are darker than their backs.
Male and Female Differences
Male serra antwrens of the F. s. serrana type have a white stripe above their eye. This stripe goes down their neck and along the side of their chest. Their head and back are reddish-brown. Their wings are brownish-black with white tips. Their tail is black with white tips on the feathers. Their face, throat, and belly are black.
Female serra antwrens look different from the males. They have a wide black band through their eye. Their entire belly area is a creamy white color.
Differences Between Subspecies
Males of the F. s. interposita and F. s. littoralis types look quite different from the F. s. serrana males. They have very dark brown or black backs. Their white stripe above the eye is thin or almost gone. They have very little white on their wings or tail. Also, they have no white on their bellies.
Female F. s. interposita and F. s. littoralis look very much alike. They are slightly different from the F. s. serrana female. Their bellies are a pale buff color instead of creamy white.
Where Do Serra Antwrens Live?
Serra Antwren Habitats
The different types of serra antwrens live in specific areas:
- F. s. serrana: Found from eastern Minas Gerais to central Espírito Santo in Brazil.
- F. s. interposita: Lives in the Paraíba do Sul valley in southeastern Minas Gerais and northwestern Rio de Janeiro state.
- F. s. littoralis: Found separately from the others, along the coast of Rio de Janeiro state, including nearby islands.
Scientists recently found F. s. serrana birds further north in Espírito Santo. It's not clear if these birds are a separate group or part of a larger population.
What Kind of Places Do They Like?
The F. s. serrana and F. s. interposita types live in the lower parts of forests. They like the edges of semi-wet evergreen forests, younger forests that have grown back, and drier scrublands. The F. s. serrana type especially likes forests on rocky, poor soils, up to 1,550 meters (5,085 feet) above sea level. The F. s. interposita type prefers younger forests near the Paraíba do Sul river. It lives at lower elevations, up to 700 meters (2,297 feet). Both of these types have also started living in Eucalyptus tree farms in Minas Gerais.
The F. s. littoralis type lives only in a special coastal area called restinga. This area has sandy soil and is full of dense bushes, cacti, and bromeliad plants.
Serra Antwren Behavior
Movement and Daily Life
Serra antwrens are thought to stay in the same area all year round. They do not migrate to other places.
What Do Serra Antwrens Eat?
Serra antwrens eat insects, spiders, and other small arthropods. They usually look for food alone, in pairs, or in family groups. Sometimes, they join other bird species to hunt for food together.
They typically search for food about 1 to 2 meters (3 to 7 feet) above the ground. However, they will also look for food on the ground or as high as 4 meters (13 feet) up. They are very active in thick plants. They mostly pick prey off leaves, vines, branches, and stems while sitting on a perch. They might also make short jumps to reach the underside of leaves. We don't know much about how the F. s. littoralis type finds its food, but it also picks prey while perched.
Reproduction and Life Cycle
The F. s. littoralis type of serra antwren builds a cup-shaped nest. It uses dry leaves, bark, thin fibers (especially from cacti), and spiderwebs. The nest is usually built in a fork of a branch, about 3.5 meters (11.5 feet) off the ground. A female usually lays two eggs. Not much else is known about how this type, or the other two types, reproduce.
How Do Serra Antwrens Communicate?
The songs and calls of the three serra antwren types are very similar. Their song is a "monotonous series of dry chup notes." They sing these notes at the same pitch and speed, sometimes up to 50 times in a row. They might pause briefly during their song.
They also make a "short, downward-sloping, nasal whine" that can have up to 20 notes. Another call is a "high-pitched, squeaky, two-syllable kee-ip note." They might say this note alone, or repeat it with long breaks, or in short bursts. Both male and female antwrens sing, and they usually do so in the morning.
Serra Antwren Status
The IUCN (International Union for Conservation of Nature) has listed the serra antwren as a species of "Least Concern." This means it is not currently in danger of disappearing. It lives in a large area, but its population size is unknown and seems to be decreasing. No immediate threats have been found.
The two types that live inland are considered fairly common in their local areas. The F. s. serrana type lives in two national parks, which helps protect it. Because these birds can live in forests that are growing back and in scrublands, they might be less affected by human changes than birds that only live in untouched forests.
When the coastal F. s. littoralis type was considered a separate species, it was first listed as "Critically Endangered" and then as "Endangered." This was because its habitat was shrinking and being broken up by human activities. Brazilian authorities still consider this type to be Endangered.
