I read something several days ago that stated that only three species of birds breed exclusively on the Antarctic Continent. I never thought about that before and did a little research regarding that statement. It set my imagination at work, though I have no intention of visiting Antarctica, even during its chilly summer.
Snow petrels, emperor penguins and south polar skuas are the three kinds of birds that nest nowhere but on the sea coasts of Antarctica. These are hardy, adaptable birds that exploited different niches, mostly free of competition from other bird species. And each species is well adapted to its role in life. Snow petrels and skuas have even been spotted flying over the South Pole.
Snow petrels are tube-nosed birds that are pigeon-sized and have a fluttering flight. Elegant, dainty birds, they have white feathering all over, with black beaks, legs and eyes. Their white plumage hides them when their little flocks rest on icebergs, pack ice and ice floes.
Snow petrels fly low over the Southern Ocean, close to the shores of Antarctica, to ingest krill, which is a kind of shrimp, and small fish. They also scavenge seal placentas, washed-up whale carcasses and dead penguin chicks. And they are able to drink ocean water because they excrete a high-saline solution from their tubed nostrils.
It's estimated that 4,000,000 adult snow petrels nest in colonies on rocky cliffs, usually near the ocean. Each pair's nursery is deep in a rock crevice, away from skuas.
The majestic, handsome emperor penguins are also masters of Antarctica. Thousands of them nest in colonies on pack ice many miles back from the Southern Ocean. This is the only bird species in the world that does not lay eggs on some kind of soil or rock. Emperors lay on frozen water- ice.
Male and female emperors court on the Antarctic ice shelf in autumn of the southern hemisphere. Each female lays one egg, which her mate puts in a flap of feathery skin and on top of his feet so the egg doesn't touch the life-stealing ice. Through the cold, sunless winter the males huddle together for warmth as each one incubates his mate's egg. Female emperors, meanwhile, went back to the sea to fatten up on fish and krill.
After two months at sea, surviving females return to their rookeries to relieve their starving mates of incubating duties. Each chick has hatched and is hungry for food stored in its mother's stomach. Each female repeatedly feeds her youngster and broods it on her feet. Meanwhile, the emaciated males march to the sea to feed up and come back later to feed their progeny. This routine goes on while the ice shelf melts until the young emperors are almost right at the ocean to dive in and do their own hunting of fish and krill. The habit of incubating eggs during the southern hemisphere winter insures that emperor chicks are on their own in the southern summer when the living is easier.
Emperors are adapted to their rigorous lifestyle. They have layers of fat and dense feathering that keeps them warm. They live off much of that fat when not feeding, and store food in their stomachs for their young.
The robust, eagle-like south polar skuas are related to gulls, but have strongly-hooked beaks for killing and tearing off chunks of meat and massive, barrel-shaped chests packed with powerful flight muscles for swift flight to pursue panicky prey. These web-footed, tawny-feathered gull relatives seem to be eagles in the making.
The aggressive south polar skuas are scavengers, feeding on unattended bird eggs, dead whales, penguins and other critters they find on ice and ocean water. They are also fierce predators, quickly killing and eating penguin chicks, and any other hapless critters they happen to come across on the sea or ice. They do what they must to survive and reproduce in a harsh habitat.
Snow petrels, emperor penguins and south polar skuas are the only birds in the world endemic to the Antarctic continent, where they live, feed and breed. Most people will never see them in their Antarctic habitats, but it's intriguing to know they are there.
Friday, February 22, 2019
Monday, February 18, 2019
Petite Polar Gulls
Two kinds of small, beautiful gulls, the ivory and Ross', spend most of their lives on the vast Arctic Ocean where ocean currents and wind create leads of open water in the pack ice. These gulls add beauty and interest to that ocean, particularly in winter when few other creatures are there. Few of us will ever visit the Arctic Ocean, but it's inspiring to know that an intriguing community of animals live in that extreme habitat, including those two kinds of handsome, interesting gulls.
Both these lovely gulls are well adapted to living on the Arctic Ocean. Their small bodies allow them to function well on limited food. Ivory gulls have white feathering, which blends them into the snow and ice of the Arctic. Predators don't easily see them. Ross' gulls are light in color, camouflaging them. Both species have strong, pigeon-like flight that carries them over ice to scattered, watery leads in the ice where they get food.
Ivory gulls are fourteen inches long, a bit larger than pigeons. They are white with black legs and a gray beak, tipped with yellow. Young ivories, however, have some dark dots and blotches on their white plumage.
At all times of the year, except their breeding season, ivories travel long distances to scattered food sources. They consume the dung of meat-eating Arctic wolves and Arctic foxes, scraps of meat and fat from mammals, including seals and whales, killed by polar bears and Inuits, and any other dead birds and mammals they find along their way.
Ross' gulls are eleven inches long, about the size of pigeons, and have red legs and small, pointed, black beaks. The pretty adults have pale-gray upper wings and tails and a blush of pink underneath. They also have a black ring around their necks during the breeding season. Young Ross' have a dark W across their upper wings and back.
Year around, except during nesting time, Ross' gulls follow leads in the pack ice to find and ingest small crustaceans such as scuds, plankton and tiny fish, all of which they pick out of the water with their small, thin bills.
Obviously, each of these gull species has food sources different from the other kind of gull, reducing competition for food between them. And each gull species' bill is suited to get its food, a case of form following function. Like all living beings, these gulls are built for what they do to sustain life.
Ivory gulls and Ross' gulls nest apart from each other. Ivories nest in colonies among rocks on sea-facing cliffs and gravel-covered, polar ice in northern Greenland and on Canadian islands just west of Greenland. Each pair builds a cradle of moss, lichens and seaweed. Meanwhile, Ross' gulls nest in colonies on the ground in river valleys and deltas in northeastern Siberia. But both species winter among icebergs, ice floes and leads on the edges of the polar pack ice on the Arctic Ocean, even during the long, dark, polar night.
Ivory and Ross' gulls are fascinating in themselves, and where they live the year around, a brutal habitat we can hardly imagine. Though most of us will never see them, it's intriguing to note where and how these hardy kinds of gulls live.
Both these lovely gulls are well adapted to living on the Arctic Ocean. Their small bodies allow them to function well on limited food. Ivory gulls have white feathering, which blends them into the snow and ice of the Arctic. Predators don't easily see them. Ross' gulls are light in color, camouflaging them. Both species have strong, pigeon-like flight that carries them over ice to scattered, watery leads in the ice where they get food.
Ivory gulls are fourteen inches long, a bit larger than pigeons. They are white with black legs and a gray beak, tipped with yellow. Young ivories, however, have some dark dots and blotches on their white plumage.
At all times of the year, except their breeding season, ivories travel long distances to scattered food sources. They consume the dung of meat-eating Arctic wolves and Arctic foxes, scraps of meat and fat from mammals, including seals and whales, killed by polar bears and Inuits, and any other dead birds and mammals they find along their way.
Ross' gulls are eleven inches long, about the size of pigeons, and have red legs and small, pointed, black beaks. The pretty adults have pale-gray upper wings and tails and a blush of pink underneath. They also have a black ring around their necks during the breeding season. Young Ross' have a dark W across their upper wings and back.
Year around, except during nesting time, Ross' gulls follow leads in the pack ice to find and ingest small crustaceans such as scuds, plankton and tiny fish, all of which they pick out of the water with their small, thin bills.
Obviously, each of these gull species has food sources different from the other kind of gull, reducing competition for food between them. And each gull species' bill is suited to get its food, a case of form following function. Like all living beings, these gulls are built for what they do to sustain life.
Ivory gulls and Ross' gulls nest apart from each other. Ivories nest in colonies among rocks on sea-facing cliffs and gravel-covered, polar ice in northern Greenland and on Canadian islands just west of Greenland. Each pair builds a cradle of moss, lichens and seaweed. Meanwhile, Ross' gulls nest in colonies on the ground in river valleys and deltas in northeastern Siberia. But both species winter among icebergs, ice floes and leads on the edges of the polar pack ice on the Arctic Ocean, even during the long, dark, polar night.
Ivory and Ross' gulls are fascinating in themselves, and where they live the year around, a brutal habitat we can hardly imagine. Though most of us will never see them, it's intriguing to note where and how these hardy kinds of gulls live.
Tuesday, February 12, 2019
Gulls Wintering on Impoundments
Many times in winter over the years, I have visited the several large, human-made impoundments in southeastern Pennsylvania to experience Canada geese, snow geese, tundra swans, a variety of ducks, great blue herons, bald eagles and ring-billed gulls that regularly winter on them, but not all at once and not on every lake. These are birds that traditionally wintered on the Susquehanna and Delaware Rivers and Chesapeake and Delaware Bays, but have adapted to built impoundments.
I visited Blue Marsh Lake, a huge impoundment in Berks County, one recent mid-afternoon to see if masses of ring-billed gulls were still spending winter nights there, as they have for several years. They were, by the thousands. Ring-bills are the main wintering bird species on that built lake, resting on its water, or ice, every winter night, as other ring-bills do on many other impoundments.
Ring-billed gulls have long adapted to wintering on local inland habitats, including harvested fields, parking lots and, most recently, landfills, to get food, and on built lakes to rest in relative peace. They have been a common, wintering species here for many years, bringing a touch of rivers, estuaries and sea coasts inland.
During winter days, thousands of ring-bills concentrate at feeding sites, especially landfills. Most gull species are preadapted to scavenging in open habitats and, therefore, can make good use of landfills. But by mid-afternoon, long lines and flocks of ring-bills wing swiftly across the sky, flock after flock, as if on an aerial highway, to return to their chosen lake, including the one at Blue Marsh, for example, to spend the night in relative safety in a familiar habitat. Each gull flaps powerfully and soars gracefully over the lake and eventually sweeps down to land on it, or a gravelly beach on its shore. And all those gulls together create quite an inspiring show of beauty and grace as they land on Blue Marsh Lake and beach, as on other impoundments.
The presence of the many adaptable ring-bills on built lakes may attract other, more common, species of wintering gulls to rest on those inland impoundments, including herring, great black-backed and, maybe most recently, lesser black-backed gulls. These three kinds of gulls, plus an occasional glaucous or Iceland gull, are also adapting to wintering on inland impoundments to some extent, and feeding at landfills. Herring gulls look like larger editions of ring-bills. Great black-backs are white with black upper wings and backs and pink legs. And the smaller lesser black-backs are white with dark-gray upper wings and backs and yellow legs.
Human-made impoundments and landfills have changed the wintering habits of the more adaptable and common kinds of gulls in southeastern Pennsylvania, and North America in general, to the birds' benefit. And those gulls help bring beauty, grace and excitement to those built habitats in winter.
I visited Blue Marsh Lake, a huge impoundment in Berks County, one recent mid-afternoon to see if masses of ring-billed gulls were still spending winter nights there, as they have for several years. They were, by the thousands. Ring-bills are the main wintering bird species on that built lake, resting on its water, or ice, every winter night, as other ring-bills do on many other impoundments.
Ring-billed gulls have long adapted to wintering on local inland habitats, including harvested fields, parking lots and, most recently, landfills, to get food, and on built lakes to rest in relative peace. They have been a common, wintering species here for many years, bringing a touch of rivers, estuaries and sea coasts inland.
During winter days, thousands of ring-bills concentrate at feeding sites, especially landfills. Most gull species are preadapted to scavenging in open habitats and, therefore, can make good use of landfills. But by mid-afternoon, long lines and flocks of ring-bills wing swiftly across the sky, flock after flock, as if on an aerial highway, to return to their chosen lake, including the one at Blue Marsh, for example, to spend the night in relative safety in a familiar habitat. Each gull flaps powerfully and soars gracefully over the lake and eventually sweeps down to land on it, or a gravelly beach on its shore. And all those gulls together create quite an inspiring show of beauty and grace as they land on Blue Marsh Lake and beach, as on other impoundments.
The presence of the many adaptable ring-bills on built lakes may attract other, more common, species of wintering gulls to rest on those inland impoundments, including herring, great black-backed and, maybe most recently, lesser black-backed gulls. These three kinds of gulls, plus an occasional glaucous or Iceland gull, are also adapting to wintering on inland impoundments to some extent, and feeding at landfills. Herring gulls look like larger editions of ring-bills. Great black-backs are white with black upper wings and backs and pink legs. And the smaller lesser black-backs are white with dark-gray upper wings and backs and yellow legs.
Human-made impoundments and landfills have changed the wintering habits of the more adaptable and common kinds of gulls in southeastern Pennsylvania, and North America in general, to the birds' benefit. And those gulls help bring beauty, grace and excitement to those built habitats in winter.
Tuesday, February 5, 2019
Wintering Geese in Southeastern Pennsylvania
Several kinds of handsome geese winter on many human-made impoundments in southeastern Pennsylvania, as they do elsewhere across much of the United States. And Canada geese are, by far, the most numerous goose species regularly wintering on southeastern Pennsylvania lakes. They rest on those bodies of water in flocks of hundreds, even thousands.
Snow geese are common here, too, but only in part of each winter because they move around a lot.
And five other kinds of geese, including Atlantic brant, cackling geese and barnacle geese in the Branta genus with Canada geese, Ross's geese in the Chen genus with snow geese, and white-fronted geese in the Anser genus, winter here occasionally in single-digit numbers for the most part.
The great, noisy flocks of stately Canada geese dominate the impoundments they settle on to rest, preen and socialize. When hungry, group after group of Canadas, all honking loudly, run across the water while flapping their powerful wings, and take swift flight off the lakes, into the wind, and off to harvested corn fields to eat waste corn kernels, or to winter rye fields to pluck the green shoots of rye. When arriving at a feeding field, Canada goose flocks that trailed each other across farmland, bugling loudly all the way, stream down into the wind to a field, gang after gang, as if on an aerial highway, each bird extending its wings like parachutes.
When full of corn kernels or rye blades, flocks of Canadas run across the field, in one minute intervals, and lift off into the wind to sweep back to their resting impoundments. There each gang swings into the wind again and floats gently down to the water, as each bird's reflection races through the water to meet its bird in splashing impact.
Canada geese are a large, picturesque part of southeastern Pennsylvania in winter. Great gatherings of these big, majestic birds are always exciting to see and hear, wherever they may be. They add much life to this area's lakes and fields, all of which are human-made habitats they adapted to. But great hordes of bugling Canada geese in flight are most exciting and inspiring to see and hear at sunrise and sunset when silhouetted black before the red sky.
Those masses of elegant Canadas attract other kinds of geese to this area's lakes and farmland, especially the awe-inspiring snow geese in their boisterous, overwhelming tens of thousands, often in one giant horde.
Snows usually arrive here in mid-February and stay until almost the middle of March. Like Canadas, snow geese rest on local impoundments and fly out to feeding fields in great, writhing lines, one after another, like waves sliding up a beach. The whole mass of snows often rise from water and fields at once, with a deafening roar of beating wings and high-pitched, honking voices, and looking like a giant sheet being lifted by one end.
Snow geese feed in the same fields that Canada geese do. But snow goose hordes are so large that the snows have to move from field to field every day to get enough to eat. Snows often clean out fields, causing Canadas to move to other feeding fields, too.
Brant, cackling geese, barnacle geese and Ross's geese are all small species, hardly larger than mallard ducks. These species of petite and attractive geese have short necks, and small heads and beaks. Cackling geese are miniature editions of Canada geese and Ross's are miniature editions of snow geese. In winter, these species of smaller geese, and a few white-fronted geese, join gangs of Canada and snow geese, adding more excitement to birders when those geese are spotted among the larger ones on impoundments and in fields.
Brant, and cackling and Ross's geese, raise young on the Canadian tundra. And brant and barnacle geese hatch offspring on the coasts of Greenland.
Barnacle pairs nest on sea cliffs to hatch young away from Arctic foxes and polar bears. But when their goslings hatch, those youngsters must jump off the cliffs to the ground or water below. A few goslings are killed or injured by the impact and some get caught and eaten by Arctic foxes, but the majority of barnacle goslings survive the leap.
Look for these attractive geese this winter and into early spring, or in successive winters. They are exciting and inspiring to experience.
Snow geese are common here, too, but only in part of each winter because they move around a lot.
And five other kinds of geese, including Atlantic brant, cackling geese and barnacle geese in the Branta genus with Canada geese, Ross's geese in the Chen genus with snow geese, and white-fronted geese in the Anser genus, winter here occasionally in single-digit numbers for the most part.
The great, noisy flocks of stately Canada geese dominate the impoundments they settle on to rest, preen and socialize. When hungry, group after group of Canadas, all honking loudly, run across the water while flapping their powerful wings, and take swift flight off the lakes, into the wind, and off to harvested corn fields to eat waste corn kernels, or to winter rye fields to pluck the green shoots of rye. When arriving at a feeding field, Canada goose flocks that trailed each other across farmland, bugling loudly all the way, stream down into the wind to a field, gang after gang, as if on an aerial highway, each bird extending its wings like parachutes.
When full of corn kernels or rye blades, flocks of Canadas run across the field, in one minute intervals, and lift off into the wind to sweep back to their resting impoundments. There each gang swings into the wind again and floats gently down to the water, as each bird's reflection races through the water to meet its bird in splashing impact.
Canada geese are a large, picturesque part of southeastern Pennsylvania in winter. Great gatherings of these big, majestic birds are always exciting to see and hear, wherever they may be. They add much life to this area's lakes and fields, all of which are human-made habitats they adapted to. But great hordes of bugling Canada geese in flight are most exciting and inspiring to see and hear at sunrise and sunset when silhouetted black before the red sky.
Those masses of elegant Canadas attract other kinds of geese to this area's lakes and farmland, especially the awe-inspiring snow geese in their boisterous, overwhelming tens of thousands, often in one giant horde.
Snows usually arrive here in mid-February and stay until almost the middle of March. Like Canadas, snow geese rest on local impoundments and fly out to feeding fields in great, writhing lines, one after another, like waves sliding up a beach. The whole mass of snows often rise from water and fields at once, with a deafening roar of beating wings and high-pitched, honking voices, and looking like a giant sheet being lifted by one end.
Snow geese feed in the same fields that Canada geese do. But snow goose hordes are so large that the snows have to move from field to field every day to get enough to eat. Snows often clean out fields, causing Canadas to move to other feeding fields, too.
Brant, cackling geese, barnacle geese and Ross's geese are all small species, hardly larger than mallard ducks. These species of petite and attractive geese have short necks, and small heads and beaks. Cackling geese are miniature editions of Canada geese and Ross's are miniature editions of snow geese. In winter, these species of smaller geese, and a few white-fronted geese, join gangs of Canada and snow geese, adding more excitement to birders when those geese are spotted among the larger ones on impoundments and in fields.
Brant, and cackling and Ross's geese, raise young on the Canadian tundra. And brant and barnacle geese hatch offspring on the coasts of Greenland.
Barnacle pairs nest on sea cliffs to hatch young away from Arctic foxes and polar bears. But when their goslings hatch, those youngsters must jump off the cliffs to the ground or water below. A few goslings are killed or injured by the impact and some get caught and eaten by Arctic foxes, but the majority of barnacle goslings survive the leap.
Look for these attractive geese this winter and into early spring, or in successive winters. They are exciting and inspiring to experience.
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