Post by Eaglehawk on Sept 4, 2019 7:25:10 GMT
Bar-headed Goose - Anser indicus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Genus: Anser
Species: Anser indicus
Distribution & Habitat
The Bar-headed Goose (Anser indicus) is a goose which breeds in Central Asia in colonies of thousands near mountain lakes and winters in Central Asia, as far south as India. The summer habitat is high altitude lakes where the bird grazes on short grass. The species has been reported as migrating south from China, Kazakhstan, Mongolia and Russia before crossing the Himalaya. The bird has come to the attention of medical science in recent years as having been an early victim of the H5N1 virus, HPAI (highly pathogenic avian influenza), at Qinghai. It suffers predation from crows, foxes, ravens, sea eagles and others. The total population may, however, be increasing.
Flight
The Bar-headed Goose is though to be one of the world's highest flying birds, having been heard flying across Mount Makalu (the fifth highest mountain on earth at 27,824 ft) and apparently seen over Mount Everest (29,028 ft, although this is a second hand report with no verification) . This incredibly demanding migration has long puzzled physiologists and naturalists: "there must be a good explanation for why the birds fly to the extreme altitudes... particularly since there are passes through the Himalaya at lower altitudes, and which are used by other migrating bird species" quoted from Black & Tenney (1980). In fact bar-headed geese have never been directly tracked (using GPS or satellite logging technology) flying higher than 6,300 m, and it is now known that they apparently do take the passes through the mountains. The challenging northward migration from lowland India to breed in the summer on the Tibetan Plateau is undertaken in stages, with the flight across the Himalaya (from sea-level) being undertaken in seven hours on average. Surprisingly, despite predictable tail winds that blow up the Himalayas (in the same direction of travel as the geese), bar-headed geese spurn these winds, waiting for them to die down overnight, when they then undertake the greatest rates of climbing flight ever recorded for a bird, and sustain these climbs rates for hours on end.
Migration
The bar-headed goose is known to be well equipped for this incredibly challenging migration. It has a slightly larger wing area for its weight than other geese, which is believed to help the goose fly at high altitudes. Studies have found that they breathe more deeply and efficiently under low oxygen conditions. The haemoglobin of their blood has a higher oxygen affinity than that of other geese.
The Bar-headed Goose migrates over the Himalayas to spend the winter in parts of India (from Assam to as far south as Tamil Nadu . The winter habitat of the Bar-headed Goose is cultivated fields, where it feeds on barley, rice and wheat, and may damage crops. Birds from Kyrgyzstan have been noted to stopover in western Tibet and southern Tajikistan for 20 to 30 days before migrating further south. Some birds may show high wintering site fidelity.
Physical Description
The bird is pale grey and is easily distinguished from any of the other grey geese of the genus Anser by the black bars on its head. It is also much paler than the other geese in this genus. In flight, its call is a typical goose honking. The adult is 71–76 cm (28–30 in) and weighs 1.87-3.2 kg (4-7 lbs).
It has sometimes been separated from Anser, which has no other member indigenous to the Indian region, nor any at all to the Ethiopian, Australian, or Neotropical regions, and placed in the monotypic genus Eulabeia.
Breeding
They nest mainly on the Tibetan plateau. It lays three to eight eggs at a time in a ground nest. Intraspecific brood parasitism is noticed with lower rank females attempting to lay their eggs in the nests of higher ranking females.
Captivity
The Bar-headed Goose is often kept in captivity, as it is considered beautiful and breeds readily. Records in Britain are frequent, and almost certainly relate to escapes. However, the species has bred on several occasions in recent years and around five pairs were recorded in 2002, the most recent available report of the Rare Birds Breeding Panel. It is possible the species is becoming gradually more established in the UK. The bird is sociable and causes no problems for other birds. The "wild" population is believed to be declining in the UK due to over-hunting.
Slowed metabolism helps migrating geese soar
by eLife
One of the bar-headed geese involved in the study, prior to flight training with foster parent Jessica Meir on a bicycle. Credit: Meir, York et al.
Researchers have shed new light on how some geese can fly high for long periods of time, according to a study published today in eLife.
The team collected the first ever cardiorespiratory measurements of bar-headed geese flying in a wind tunnel at a simulated altitude of 9,000m. They discovered that the animals are able to maintain flight in these low-oxygen conditions via a reduction in their metabolism.
Bar-headed geese are famed for migratory flight at extreme altitudes, having been directly tracked flying as high as 7,290m, and anecdotally reported reaching 9,000m. Previous research suggests these birds have several adaptations that allow them to maximise their oxygen usage at high altitudes, such as the ability to deliver oxygen efficiently to individual cells. But until now, no studies have comprehensively measured the physiology of bar-headed geese during flight in low-oxygen conditions, partly because there are few wind tunnels in the world suitable to carry out such experiments.
To address this gap in our knowledge, a research team from the University of British Columbia (UBC), Vancouver, Canada, imprinted a flock of bar-headed geese born and raised at sea-level, and trained them to fly in a wind tunnel. The group was led by Jessica Meir, a postdoctoral researcher in Bill Milsom's lab at UBC at the time the study was carried out, along with Julia York, an undergraduate researcher, currently a Ph.D. candidate at the University of Texas at Austin, US.
They found that six of the seven birds that could fly in the tunnel were capable of flight in moderately low-oxygen levels equal to around 5,500m—the altitudes at which their wild counterparts typically fly. Three of the birds were also willing to fly in severely low-oxygen conditions, equal to altitudes of roughly 9,000m, for at least the short duration of the flights carried out in the study.
"We were surprised to find their heart rate during flights in reduced oxygen was no higher than that during flights in normal oxygen levels," York says. "We also saw that the temperature in their veins decreased during our simulated flights, which is hypothesised to significantly increase the amount of oxygen they can carry in their blood. Our data suggest the animals are able to reduce their metabolism in line with the reduced amount of oxygen available, without evidence of an oxygen limitation.
Milsom adds that determining how these results relate to the longer migratory flights of bar-headed geese at high altitudes will require further work to measure the physiological variables in the wild, or during longer flights in both normal and low-oxygen conditions.
"These initial measurements pave the way for future experiments that we believe will significantly move the field of high-altitude physiology forward," Meir explains. "Additionally, our findings have relevance to all physiological and biomedical fields involving animals and humans in low-oxygen environments, such as medical conditions including heart attacks and strokes, or procedures like organ transplants."
This study is one of a number of experiments carried out by Meir during her research career to see how animals cope in extreme conditions. Her previous work has involved travelling to Antarctica to study the adaptations of emperor penguins to long underwater dives.
Meir is currently a NASA astronaut, scheduled to launch to the International Space Station for a six-month mission on September 25, 2019, where she will support research into a diversity of space sciences including how long-duration spaceflight affects human physiology.
phys.org/news/2019-09-metabolism-migrating-geese-soar.html
Journal Reference:
Jessica U Meir et al, Reduced metabolism supports hypoxic flight in the high-flying bar-headed goose (Anser indicus), eLife (2019). DOI: 10.7554/eLife.44986
Abstract
The bar-headed goose is famed for migratory flight at extreme altitude. To better understand the physiology underlying this remarkable behavior, we imprinted and trained geese, collecting the first cardiorespiratory measurements of bar-headed geese flying at simulated altitude in a wind tunnel. Metabolic rate during flight increased 16-fold from rest, supported by an increase in the estimated amount of O2 transported per heartbeat and a modest increase in heart rate. The geese appear to have ample cardiac reserves, as heart rate during hypoxic flights was not higher than in normoxic flights. We conclude that flight in hypoxia is largely achieved via the reduction in metabolic rate compared to normoxia. Arterial Po2 was maintained throughout flights. Mixed venous PO2 decreased during the initial portion of flights in hypoxia, indicative of increased tissue O2 extraction. We also discovered that mixed venous temperature decreased during flight, which may significantly increase oxygen loading to hemoglobin.
elifesciences.org/articles/44986
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Genus: Anser
Species: Anser indicus
Distribution & Habitat
The Bar-headed Goose (Anser indicus) is a goose which breeds in Central Asia in colonies of thousands near mountain lakes and winters in Central Asia, as far south as India. The summer habitat is high altitude lakes where the bird grazes on short grass. The species has been reported as migrating south from China, Kazakhstan, Mongolia and Russia before crossing the Himalaya. The bird has come to the attention of medical science in recent years as having been an early victim of the H5N1 virus, HPAI (highly pathogenic avian influenza), at Qinghai. It suffers predation from crows, foxes, ravens, sea eagles and others. The total population may, however, be increasing.
Flight
The Bar-headed Goose is though to be one of the world's highest flying birds, having been heard flying across Mount Makalu (the fifth highest mountain on earth at 27,824 ft) and apparently seen over Mount Everest (29,028 ft, although this is a second hand report with no verification) . This incredibly demanding migration has long puzzled physiologists and naturalists: "there must be a good explanation for why the birds fly to the extreme altitudes... particularly since there are passes through the Himalaya at lower altitudes, and which are used by other migrating bird species" quoted from Black & Tenney (1980). In fact bar-headed geese have never been directly tracked (using GPS or satellite logging technology) flying higher than 6,300 m, and it is now known that they apparently do take the passes through the mountains. The challenging northward migration from lowland India to breed in the summer on the Tibetan Plateau is undertaken in stages, with the flight across the Himalaya (from sea-level) being undertaken in seven hours on average. Surprisingly, despite predictable tail winds that blow up the Himalayas (in the same direction of travel as the geese), bar-headed geese spurn these winds, waiting for them to die down overnight, when they then undertake the greatest rates of climbing flight ever recorded for a bird, and sustain these climbs rates for hours on end.
Migration
The bar-headed goose is known to be well equipped for this incredibly challenging migration. It has a slightly larger wing area for its weight than other geese, which is believed to help the goose fly at high altitudes. Studies have found that they breathe more deeply and efficiently under low oxygen conditions. The haemoglobin of their blood has a higher oxygen affinity than that of other geese.
The Bar-headed Goose migrates over the Himalayas to spend the winter in parts of India (from Assam to as far south as Tamil Nadu . The winter habitat of the Bar-headed Goose is cultivated fields, where it feeds on barley, rice and wheat, and may damage crops. Birds from Kyrgyzstan have been noted to stopover in western Tibet and southern Tajikistan for 20 to 30 days before migrating further south. Some birds may show high wintering site fidelity.
Physical Description
The bird is pale grey and is easily distinguished from any of the other grey geese of the genus Anser by the black bars on its head. It is also much paler than the other geese in this genus. In flight, its call is a typical goose honking. The adult is 71–76 cm (28–30 in) and weighs 1.87-3.2 kg (4-7 lbs).
It has sometimes been separated from Anser, which has no other member indigenous to the Indian region, nor any at all to the Ethiopian, Australian, or Neotropical regions, and placed in the monotypic genus Eulabeia.
Breeding
They nest mainly on the Tibetan plateau. It lays three to eight eggs at a time in a ground nest. Intraspecific brood parasitism is noticed with lower rank females attempting to lay their eggs in the nests of higher ranking females.
Captivity
The Bar-headed Goose is often kept in captivity, as it is considered beautiful and breeds readily. Records in Britain are frequent, and almost certainly relate to escapes. However, the species has bred on several occasions in recent years and around five pairs were recorded in 2002, the most recent available report of the Rare Birds Breeding Panel. It is possible the species is becoming gradually more established in the UK. The bird is sociable and causes no problems for other birds. The "wild" population is believed to be declining in the UK due to over-hunting.
Slowed metabolism helps migrating geese soar
by eLife
One of the bar-headed geese involved in the study, prior to flight training with foster parent Jessica Meir on a bicycle. Credit: Meir, York et al.
Researchers have shed new light on how some geese can fly high for long periods of time, according to a study published today in eLife.
The team collected the first ever cardiorespiratory measurements of bar-headed geese flying in a wind tunnel at a simulated altitude of 9,000m. They discovered that the animals are able to maintain flight in these low-oxygen conditions via a reduction in their metabolism.
Bar-headed geese are famed for migratory flight at extreme altitudes, having been directly tracked flying as high as 7,290m, and anecdotally reported reaching 9,000m. Previous research suggests these birds have several adaptations that allow them to maximise their oxygen usage at high altitudes, such as the ability to deliver oxygen efficiently to individual cells. But until now, no studies have comprehensively measured the physiology of bar-headed geese during flight in low-oxygen conditions, partly because there are few wind tunnels in the world suitable to carry out such experiments.
To address this gap in our knowledge, a research team from the University of British Columbia (UBC), Vancouver, Canada, imprinted a flock of bar-headed geese born and raised at sea-level, and trained them to fly in a wind tunnel. The group was led by Jessica Meir, a postdoctoral researcher in Bill Milsom's lab at UBC at the time the study was carried out, along with Julia York, an undergraduate researcher, currently a Ph.D. candidate at the University of Texas at Austin, US.
They found that six of the seven birds that could fly in the tunnel were capable of flight in moderately low-oxygen levels equal to around 5,500m—the altitudes at which their wild counterparts typically fly. Three of the birds were also willing to fly in severely low-oxygen conditions, equal to altitudes of roughly 9,000m, for at least the short duration of the flights carried out in the study.
"We were surprised to find their heart rate during flights in reduced oxygen was no higher than that during flights in normal oxygen levels," York says. "We also saw that the temperature in their veins decreased during our simulated flights, which is hypothesised to significantly increase the amount of oxygen they can carry in their blood. Our data suggest the animals are able to reduce their metabolism in line with the reduced amount of oxygen available, without evidence of an oxygen limitation.
Milsom adds that determining how these results relate to the longer migratory flights of bar-headed geese at high altitudes will require further work to measure the physiological variables in the wild, or during longer flights in both normal and low-oxygen conditions.
"These initial measurements pave the way for future experiments that we believe will significantly move the field of high-altitude physiology forward," Meir explains. "Additionally, our findings have relevance to all physiological and biomedical fields involving animals and humans in low-oxygen environments, such as medical conditions including heart attacks and strokes, or procedures like organ transplants."
This study is one of a number of experiments carried out by Meir during her research career to see how animals cope in extreme conditions. Her previous work has involved travelling to Antarctica to study the adaptations of emperor penguins to long underwater dives.
Meir is currently a NASA astronaut, scheduled to launch to the International Space Station for a six-month mission on September 25, 2019, where she will support research into a diversity of space sciences including how long-duration spaceflight affects human physiology.
phys.org/news/2019-09-metabolism-migrating-geese-soar.html
Journal Reference:
Jessica U Meir et al, Reduced metabolism supports hypoxic flight in the high-flying bar-headed goose (Anser indicus), eLife (2019). DOI: 10.7554/eLife.44986
Abstract
The bar-headed goose is famed for migratory flight at extreme altitude. To better understand the physiology underlying this remarkable behavior, we imprinted and trained geese, collecting the first cardiorespiratory measurements of bar-headed geese flying at simulated altitude in a wind tunnel. Metabolic rate during flight increased 16-fold from rest, supported by an increase in the estimated amount of O2 transported per heartbeat and a modest increase in heart rate. The geese appear to have ample cardiac reserves, as heart rate during hypoxic flights was not higher than in normoxic flights. We conclude that flight in hypoxia is largely achieved via the reduction in metabolic rate compared to normoxia. Arterial Po2 was maintained throughout flights. Mixed venous PO2 decreased during the initial portion of flights in hypoxia, indicative of increased tissue O2 extraction. We also discovered that mixed venous temperature decreased during flight, which may significantly increase oxygen loading to hemoglobin.
elifesciences.org/articles/44986