Answer:
Milton says that numerous little birds hatch from the egg that soon right after they chirp for attention and satisfaction.
"Meanwhile the tepid Caves, and Fens and shores
Their Brood as numerous hatch from th' Egg that soon
Bursting with kindly38 rupture forth disclos'd
Their callow" (line 419-20)
The younglings are not yet covered with feathers but soon will be. The parents gather their children and fly off into the sublime air with little care for what's beneath them, but there underneath the clouds on a cliff, an eagle and a stork observe the sky and land.
"young, but feather'd soon and fledge (line 420)
They summ'd their Pens41 and soaring th' air sublime
in prospect; there the Eagle and the Stork
On Cliffs and Cedar tops their Eyries"
The eagle is wiser than the other. Both are of common size.
"build
Part loosely wing the Region, part more wise (line 425)
In common, rang'd in figure wedge their way,"
Birds are very intelligent when it comes to the seasons. Birds will set forth and fly southwards high over seas and land with light airy wings, making it easy for the wind to carry them through while the bird steers its way.
"Intelligent of seasons, and set forth
Their Aery Caravan high over Seas
Flying, and over Lands with mutual wing
Easing their flight; so steers the prudent Crane" (line 430)
A bird is born to fly within the sky and while within the air, birds are very light.
"Her annual Voyage, borne on Winds; the Air
Floats,"
Step-by-step explanation:
Milton's description is fully realistic in every way. Everything he says to describe birds is how we know them today. Intelligent, swift through the air, follow the seasons, learn how to fly, and find their own resource for themselves and their children. One major thing about birds though is their natural instinct for survival of the fittest. If they see one kid is not as strong as the other, they will throw it out so it gives the stronger chicks a higher chance of survival.