San Benedicto Rock Wren
Encyclopedia
The San Benedicto Rock Wren (Salpinctes obsoletus exsul) is a small extinct passerine
which was endemic to San Benedicto Island
in the Revillagigedo Islands
off Mexico
. It was a subspecies of the Rock Wren
.
San Benedicto is a volcano
, like all the Revillagigedo group. Unlike for example Roca Partida
, it was still active in recent times. On August 1, 1952, lava fountains started to break out of the Boquerón vent, located in a rift between the two older volcano cones. By around 8:45, ejecta
were thrown up for several km in a severe Vulcanian eruption
of magnitude 3 on the Volcanic Explosivity Index
scale; pyroclastic flow
s rolled over the island.
Two weeks later, the entire island was covered in ash and pumice
up to 10 ft (3 m) high. Bárcena crater, nearly 1100 ft high (over 300 m), rose where the wren's habitat had been before. The birds were never seen again.
This rock wren was the only endemic terrestrial bird on San Benedicto. It was one of but two landbirds on San Benedicto, sharing the island with Western Ravens which were wiped out by the eruption too.
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
which was endemic to San Benedicto Island
San Benedicto Island
San Benedicto, formerly Santo Tomás, is an uninhabited island, and third largest island of the Revillagigedo Islands, located in the Pacific at ....
in the Revillagigedo Islands
Revillagigedo Islands
The Revillagigedo Islands or Revillagigedo Archipelago are a group of four volcanic islands in the Pacific Ocean, known for their unique ecosystem...
off Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. It was a subspecies of the Rock Wren
Rock Wren
The Rock Wren is a small songbird of the wren family. It is the only species in the genus Salpinctes.The 12 cm long adults have grey-brown upperparts with small black and white spots and pale grey underparts with a light brown rump...
.
Extinction
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
, like all the Revillagigedo group. Unlike for example Roca Partida
Roca Partida
Roca Partida is the smallest of the Revillagigedo Islands in Mexico, administrated by the state of Colima. It is uninhabited, with an area of only ....
, it was still active in recent times. On August 1, 1952, lava fountains started to break out of the Boquerón vent, located in a rift between the two older volcano cones. By around 8:45, ejecta
Ejecta
Ejecta can mean:*In volcanology, particles that came out of a volcanic vent, traveled through the air or under water, and fell back on the ground surface or on the ocean floor...
were thrown up for several km in a severe Vulcanian eruption
Vulcanian eruption
The term Vulcanian was first used by Giuseppe Mercalli, witnessing the 1888-1890 eruptions on the island of Vulcano. His description of the eruption style is now used all over the world for eruptions characterised by a dense cloud of ash-laden gas exploding from the crater and rising high above the...
of magnitude 3 on the Volcanic Explosivity Index
Volcanic Explosivity Index
The Volcanic Explosivity Index was devised by Chris Newhall of the U.S. Geological Survey and Stephen Self at the University of Hawaii in 1982 to provide a relative measure of the explosiveness of volcanic eruptions....
scale; pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...
s rolled over the island.
Two weeks later, the entire island was covered in ash and pumice
Pumice
Pumice is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid...
up to 10 ft (3 m) high. Bárcena crater, nearly 1100 ft high (over 300 m), rose where the wren's habitat had been before. The birds were never seen again.
This rock wren was the only endemic terrestrial bird on San Benedicto. It was one of but two landbirds on San Benedicto, sharing the island with Western Ravens which were wiped out by the eruption too.