Tahiti petrel facts for kids
Quick facts for kids Tahiti petrel |
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Pseudobulweria
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rostrata
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The Tahiti petrel (Pseudobulweria rostrata) is a medium-sized seabird with dark brown and white feathers. You can find these birds all over the Pacific Ocean. There are two main types, called subspecies. One, P. r. rostrata, nests in the west-central Pacific. The other, P. r. trouessarti, nests in the warmer, tropical and subtropical parts.
The Tahiti petrel belongs to a bird family called Procellariidae. It's the most studied bird in its group, the Pseudobulweria genus. Sadly, this bird is considered near threatened by the IUCN Red List. This means it could become endangered if we don't protect it. Threats like rats, cats, pigs, dogs, mining, and bright lights at night are big problems for them.
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Discovering the Tahiti Petrel
The first Tahiti petrel was found and described in 1848 by Titian Peale in Tahiti. Later, in 1917, scientists realized there were two different subspecies. They named them rostrata and trouessarti. The trouessarti subspecies has a stronger bill, which is like its beak.
These two types also live in different places. P. r. rostrata nests in the west-central Pacific Ocean. P. r. trouessarti nests in the tropical and subtropical Pacific. At first, the Tahiti petrel was thought to be part of the Pterodroma group. But new studies of their genes showed it actually belongs to the Pseudobulweria genus. This group includes the Tahiti petrel, Beck's petrel, Fiji petrel, and Mascarene petrel. Sadly, the Saint Helena petrel from this group is now extinct.
What Does the Tahiti Petrel Look Like?
Adult Tahiti petrels weigh between 315 and 506 grams. Their wings can spread out to about 104.5 centimeters wide. The bird's total length is usually between 38 and 42 centimeters.
You can spot this bird by its wedge-shaped tail and long wings and neck. It has a small head and a black, strong, rounded bill. Its eyes are dark brown. The body is mostly dark brown with a white belly. Under their wings, they have a faint white line. Young birds look very similar to adults. Female birds are usually a bit smaller.
From far away, it can be tricky to tell the Tahiti petrel apart from other petrels. But the Tahiti petrel has narrower wings that stay straight when it flies. This makes it look a bit like an albatross. The Phoenix petrel, which is similar but smaller, flies with its wings bent forward. Up close, the Tahiti petrel has a smaller bill than the Phoenix petrel. It also has a white line under its wings, which the Phoenix petrel doesn't have.
The Atlantic petrel also has a white belly, like the Tahiti petrel. But you can tell the Atlantic petrel apart by its brown undertail. It also has a dark patch around its eye and plain underwings.
Where Do Tahiti Petrels Live?
Even though it's called the Tahiti petrel, this bird lives across the entire Pacific Ocean. As we learned, the two subspecies nest in different areas:
- P. r. rostrata is known to nest in American Samoa, the Gambier Islands, Marquesas Islands, and Society Islands. It might also nest on Rarotonga in the Cook Islands.
- P. r. trouessarti is known to nest in New Caledonia and Vanuatu.
When they are not nesting, these birds can be found in Australia, Guam, and the Federated States of Micronesia. Some individual birds have even been seen far away in places like Chile, Japan, and Papua New Guinea.
Tahiti petrels need both land and sea to survive. They live in both shallow and deep marine habitats. On land, they prefer shrubland and forest habitats. In the ocean, they like water that is warmer than 25°C (77°F). Because of this, events like El Niño can affect how many of them are found in the East Pacific.
Tahiti Petrel Behaviour
Reproduction and Life Cycle
When Tahiti petrels nest, they lay their eggs high up in mountains or forests. This is why they prefer to breed on volcanic islands. They breed all year long, but most eggs are laid between March and July. Most young birds are ready to fly between July and September.
In New Caledonia, P. r. trouessarti builds nests in cracks and burrows up to 500 meters high. In other areas, these birds might nest as high as 1,900 meters. We don't have much information about how long the eggs take to hatch or how the chicks are raised.
What Do Tahiti Petrels Eat?
We don't know much about what Tahiti petrels eat. But we have seen them grab prey from the surface of the water. They don't dive deep for food. For example, they have been seen hunting sea skaters. They also sometimes feed near other seabirds and pilot whales.
When scientists have looked inside their stomachs, they found parts of deep-sea fish and cephalopods (like squid). They also found fish that live near the bottom, like hatchetfish and snake mackerels. Since these petrels don't dive, finding deep-sea fish means they might eat dead animals. Or they might catch fish that swim closer to the surface at night.
How Do Tahiti Petrels Communicate?
When flying or on their nesting grounds, P. r. rostrata makes a long series of whistles. This call ends with a hooting sound. In American Samoa, their ground call has seven parts. They use a shorter version when flying. The first part of their call, a "ti-ti" sound, is also heard in 20 other petrel species. Researchers think they might use echolocation (like bats) to find their way in the dark or fog near their colonies.
On the other hand, P. r. trouessarti makes upward-sloping whistles when flying. On the ground, they often make braying whistles. These calls can have many variations. These differences might show if the bird is male or female, how it's feeling, or even its unique identity.
Protecting the Tahiti Petrel
Population Status
The Pseudobulweria group is one of the most endangered seabird groups. The Fiji petrel, Beck's petrel, and Mascarene petrel are all critically endangered. The Tahiti petrel is considered near threatened by the 2018 IUCN Red List.
We don't know much about the population numbers in Fiji, American Samoa, and the Cook Islands. However, the number of breeding pairs is going down in the Marquesas Islands, Tahiti, and Mo'orea. There are fewer than 500 pairs in Marquesas, fewer than 1,000 in Tahiti, and fewer than several thousand in Mo'orea. Overall, scientists think there are about 10,000 to 19,999 adult Tahiti petrels. The total number of individuals is estimated to be between 20,000 and 30,000.
What Threats Do They Face?
The P. r. rostrata subspecies is threatened by feral cats and introduced rats. These animals hunt the petrels. Building roads in mountain areas has made it easier for predators to reach the petrels' nesting sites. This includes natural predators like the Swamp harrier.
The P. r. trouessarti subspecies is threatened by feral pigs, dogs, and cats. Nickel mining is also a problem. Dogs and pigs dig the petrels out of their nests. Mining can cause the birds to eat harmful materials, which makes it harder for them to have healthy chicks. Also, in New Caledonia and French Polynesia, bright coastal light pollution can confuse young birds and cause them to die. Researchers are also looking into the relationship between Tahiti petrels and Wedge-tailed Shearwaters. They compete a lot for nesting burrows.
What Is Being Done to Help?
The KNS Mining Society plans to reduce mining in the Koniambo Massif mountain range in New Caledonia. There, a group called the Société Calédonienne d'Ornithologie (SCO) is working to help birds confused by light pollution. They collect these birds and release them safely. Since we still don't know all the population numbers, scientists will keep counting and watching these birds. This will help them understand what else is needed to protect the Tahiti petrel.
