The gravel looks much less comfortable than the twig-and-feather nest the hawks created, but apparently falcons prefer what they call a "scrape" as a nesting place, and gravel is considered a prime material by the birds.
Momma - the larger of the pair, who mate for life - just rearranged herself on the eggs, of which there are at least three, at least that I could count. There may have been one more hiding under her other side.
Incubation period is 29 - 33 days; We Energies had no information on when the eggs were laid, so when they will hatch is anyone's guess. The chicks are said to have disproportionately large feet - I'm looking forward to seeing them.
When diving for prey (they eat other birds - and happily, they help keep the pigeon population down), they reach speeds in excess of 200 mph. And still can snatch the catch of the day out of mid-flight.