I read a short story as a child that revolved around the people of earth observing a distant object in space approaching. Over time as the distant speck got closer it was observed to be a giant bird and the earth itself began to tremble and quake as if our planet was the bird's egg. Does anyone know the name of this story?
There are (at least) two stories in the planets-are-the-eggs-of-giant-space-birds microgenre: "Born of the Sun" by Jack Williamson and "And Lo! The Bird" by Nelson S. Bond. In Williamson's story planets and moons are observed hatching, but no "mother bird" is seen flying in from interstellar space; in fact (as the title indicates) our sun is the "mother bird", the bird-like hatchlings are baby stars. The story you described is the other one, Nelson S. Bond's "And Lo! The Bird". It was a favorite of Harlan Ellison, who is quoted at the end of this post.
The story begins with the narrator, a newspaper reporter, interviewing an astronomer who has seen something very strange in his telescope:
"A bird," he said.
I glanced at him in swift surprise. "A bird?" I felt like smiling, but the look in his eyes did not encourage mirth.
"A bird," he repeated. "Far in the depths of space. The telescope was directed toward Pluto, farthermost planet of our solar system. A body almost four thousand millions of miles from Earth.
"And at that distance—" he spoke with a painful deliberation—"at that incredible distance, I saw a bird!"
The bird heads in towards the sun, in search of the lost planet Vulcan:
Briefly, as if searching for something, it flew in a wide circle in an orbit between Mercury and the sun.
Abramson believed it was looking for something. For something it could not find because it was no longer there. Astronomers believed, said Abramson, that at one time there had been another planet circling between Mercury and the sun. Some watchers of the sky had seen this as late as the Eighteenth Century, and had called it Vulcan. Vulcan had disappeared; perhaps it had fallen into the sun. So thought Abramson. And so, apparently, the bird decided too, for after a fruitless search it winged its way outward from the sun to approach the closest of its brood still remaining intact.
Mercury is first to hatch:
I saw the first thin splitting of Mercury's shell, and the curious fluid ichor which seeped from a dying world. I watched the grisly emergence of that small, wet, scrawny thing—raw simulacrum of its monstrous parent—from the egg in which it had lain for whatever incalculable era was the gestation period of a creature vast as space and as old as time. I saw the mother bird stretch forth its giant beak and help its fledgling rid itself of a peeling, needless shell; stood horrified to watch the younger bird emerge and flap its new, uncertain wings, drying them in the burning rays of the star which had been its incubator.
A plan is hatched to save the Earth:
"I believe," he told a special emergency committee appointed by the President, "the bird has come to hatch the brood of young it deposited God knows how many centuries ago about that incubating warmth which is our sun. Its wisdom or instinct tells it that the time of emergence is now; it has come to help its fledglings shed their shells.
"But we know that mother birds, alone and unaided, do not hatch their young. They will aid a struggling chick to crack its shell, but they will never begin the liberating action. With an uncanny second sense, they seem to know which eggs have failed to develop life within them. Such eggs they never disturb.
"Therein, gentlemen, lies our only hope. The shell of Earth is forty miles in thickness. We have our engineers and technicians; we have the atomic bomb. If mankind is to live, the host to which we are but parasites must die. That is my only solution. I leave the rest to you."
So there is no real ending to this story. As I said before, I don't know why I'm bothering to write it. The answer is not ready to be given. If we succeed, there will be ample time to tell the tale properly—the whole great story, fully documented, of the battle being waged on the hot Arizona sands. And if we fail—well, then there will be no reason for this writing. There will be none to read it.
The bird is not the greatest of our fears. If when it comes from Venus it finds here a quiet, lifeless, unresponsive shell, it will move outward—we believe and pray—to Mars, then Jupiter, and thence beyond.
That is the end we hope to bring about. Soon, now, our probing needles will penetrate Earth's shell, will dip beneath the crust and into the tegument of that horror which sleeps within us.
But we have another more tormenting fear. It is that before the mother bird approaches us the fledgling may awake and seek to gain its freedom from the shell encasing it. If this should happen, Abramson has warned, our work must then proceed with lightning speed. For let that fledgling once begin to knock, then it must die—or all mankind is doomed.
That is the other reason why I write. To keep from thinking thoughts I dare not think. Because:
Because early this morning, Earth began to knock. . . .
There have been few writers in my well-read life whose work I've been more in love with than yours. I came upon you when you were in fullest flower. I was in high school, 1950 I think, and I was a reader of Blue Book magazine. And it was there that I came across "And Lo! The Bird," which I suspect I've reread more than a hundred times; suspect I've read it aloud to high school and writing classes possibly half a hundred; and don't suspect, but KNOW, I've recommended it to readers MORE than a hundred times.