New Zealand wren facts for kids
Quick facts for kids New Zealand wrensTemporal range: Miocene to present
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| The winter range of the New Zealand rock wren remains a scientific mystery | |
Scientific classification  |
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Suborder: | Acanthisitti Wolters, 1977 |
| Family: | Acanthisittidae Sundevall, 1872 |
| Genera | |
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Acanthisitta |
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The New Zealand wrens are a group of very small birds found only in New Zealand. They belong to a special bird family called Acanthisittidae.
Long ago, there were six different kinds of New Zealand wrens. They were grouped into four or five different genera. But today, only two kinds of these birds are still alive.
These wrens look and act a bit like the "true wrens" you might find in other parts of the world. However, they are not closely related to them at all. Scientists believe New Zealand wrens are a very old and unique group of birds. They might even be a separate branch on the bird family tree!
New Zealand wrens mostly eat insects. They search for food in the forests of New Zealand. One type, the New Zealand rock wren, lives only in high, cold mountain areas.
Both of the wrens still alive today are not very good at flying. Four of the five kinds that are now extinct were also known or thought to be unable to fly. This is very rare for small birds! They are among the only small birds known to have lost the ability to fly.
The wrens usually have dull colors, like brown and green feathers. They stay with one partner to raise their young. They lay their eggs in small nests in trees or among rocks. These birds are active during the day and tend to stay in one area, not flying far.
Sadly, many New Zealand wrens disappeared after people arrived in New Zealand. Two kinds became extinct after the Māori arrived, along with the Polynesian rat. We only know about these birds from their fossil bones.
Another wren, Lyall's wren, disappeared from the main islands. It survived for a while only on a small island called Stephens Island. This bird and the bushwren became extinct after Europeans arrived. The bushwren was last seen in 1972.
Of the two kinds left, the rifleman is still common on both the North and South Islands. The New Zealand rock wren lives only in the mountains of the South Island and is considered vulnerable, meaning it needs protection.
A Unique Bird Family
The New Zealand wrens are a very special group of birds. Scientists have studied them a lot to understand where they fit in the bird family tree. For a long time, it was debated if they were related to songbirds or another group.
Newer studies suggest that New Zealand wrens are so unique, they might be from a very ancient group of birds. This group separated from other birds a very long time ago. Some scientists think their ancestors might have arrived in New Zealand when it was still connected to a supercontinent called Gondwana, millions of years ago. Others think they flew here later from Australia or Antarctica.
Scientists believe that most of New Zealand was under water during a time called the Oligocene period. This event caused a "genetic bottleneck," meaning only a few birds survived. The wrens we see today are likely descendants of those survivors. The oldest known fossil of a New Zealand wren is called Kuiornis indicator. It lived during the Miocene period.
Scientists use Mitochondrial DNA to study how different species are related. A study in 2016 helped us understand the wren family better. It showed that some of the extinct stout-legged wrens were actually closely related to the Xenicus wrens. This means the stout-legged wrens probably evolved from ancestors with thinner legs.
Different Kinds of Wrens
Here are the different kinds of New Zealand wrens, both living and extinct:
- Genus Acanthisitta
- Rifleman: Acanthisitta chloris (This is one of the two living species.)
- Genus Xenicus
- †Bushwren, Xenicus longipes (Now extinct)
- New Zealand rock wren or South Island wren, Xenicus gilviventris (This is the other living species.)
- Genus Traversia
- †Lyall's wren or Stephens Island wren, Traversia lyalli (Now extinct)
- Genus Pachyplichas
- †South Island stout-legged wren or Yaldwyn's wren, Pachyplichas yaldwyni (Now extinct)
- †North Island stout-legged wren or Grant-Mackie's wren, Pachyplichas jagmi (Now extinct)
- Genus Dendroscansor
- †Long-billed wren, Dendroscansor decurvirostris (Now extinct)
- Genus Kuiornis
- †Kuiornis indicator (Now extinct)
What They Look Like
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New Zealand wrens are truly tiny birds! The rifleman is the smallest bird in all of New Zealand. They are usually between 7 to 10 centimeters long. That's about the length of your finger!
Their weight can be as little as 5–7 grams for the rifleman. That's lighter than a dollar coin! The extinct stout-legged wren was much heavier, estimated to be around 50 grams. The New Zealand rock wren weighs about 14 to 22 grams.
We only know what the feathers of four wren species looked like because European scientists saw them. All these birds had dull green and brown feathers. Most of them also had a clear stripe above their eye.
For Lyall's wren and the bushwren, males and females looked the same. But for the New Zealand rock wren, there are small differences in their feathers between males and females. The rifleman shows even bigger differences. Male riflemen have bright green upper parts, while females are duller and browner.
Interestingly, for both the New Zealand rock wren and the rifleman, the female bird is larger than the male. This is unusual for small birds! Female riflemen also have a slightly more upturned beak and a larger back claw than males.
These wrens evolved in New Zealand for millions of years without many mammals around. Because of this, some of them started to lose the ability to fly. Three species are thought to have become flightless: the stout-legged wren, the long-billed wren, and Lyall's wren. Their skeletons show they had very small breastbones, which are important for flight muscles. Old stories about Lyall's wrens on Stephens Island describe them scurrying on the ground instead of flying.
Where They Live
New Zealand wrens are found only in New Zealand. They live on the main islands and some smaller islands nearby. They haven't been found on far-off islands like the Chatham Islands.
Before humans arrived in New Zealand around 1280 AD, these wrens lived all over the North and South Islands, and on Stewart Island/Rakiura. The rifleman and bushwren lived in different types of forests. The New Zealand rock wren is special because it lives in cold, high mountain areas, from 900 meters up to 2,400 meters high. Even though it's sometimes called the South Island wren, fossils show it used to live in the North Island too.
Lyall's wren was once thought to live only on tiny Stephens Island. But fossil evidence shows it used to be found on both the North and South Islands. The stout-legged wren also lived on both islands. However, fossils of the long-billed wren have only been found in the South Island. Its bones are very rare to find.
After humans and new animals arrived in New Zealand, many wrens disappeared or their homes became much smaller. The New Zealand rock wren now only lives in the South Island, and its numbers are going down.
The rifleman's home area first shrank when forests were cut down for farms. But it has also started living in new places, like pine tree farms. It can also be found in other areas changed by humans, as long as there's native forest nearby.
Like all small birds in New Zealand, these wrens tend to stay in one place. They don't usually fly long distances or migrate. It's not known if the extinct species migrated, but it's very unlikely since three of them couldn't fly.
The New Zealand rock wren has a bit of a mystery! They live above the snow line, where it would be very hard to find food in winter. Scientists haven't found any proof that they move to lower areas during winter. But they also disappear from their usual spots. They might go into a deep sleep, like some hummingbirds do, to save energy during winter. But this hasn't been proven yet.
See also
In Spanish: Acanthisittidae para niños
