Now big changes are at hand.
"They're at what we call a downy stage," said Peter Jenny, president of The Peregrine Fund. "Big puffs of down keep them warm like a sweater. But you can see the feathers start to poke through the down."
The baby falcons are now sprouting feathers.
"The Peregrine falcon in the fastest of all living creatures. They can go in excess of 200 miles an hour in a dive."
But it'll be a couple of weeks before the the chicks actually leave the nest for short flights and they still need Mom and Dad to feed them.
Meantime they practice by flapping their wings.
The Peregrine Falcon has been called the most cosmopolitan of raptors, not because they read fancy magazines, but because they can be found almost anywhere even atop downtown office buildings.
It's population was decimated by the pesticide DDT, which the United States banned in 1972. And the Peregrine falcon was taken off the U.S. Endangered Species list in 1999.
A monitor in the One Capitol Center lobby keeps passersby entranced.
And it's nothing less than a birds-eye view into the most successful recovery of an endangered species ever.
(The web camera is attached to a nest box on the 14th floor of the One Capital Center Building, 10th and Main streets, in downtown Boise. The box is on a ledge on the northwest corner of the building.)