Peregrine falcons also hatch close together, and since it's been five days since the first young entered the world, Walters isn't optimistic for the remaining two eggs.
"It's been a long time. We had a hatch on [May 22], and you would expect if we had something going there, it should have happened by now," Walters said. The parents laid the first egg April 12, the next April 15, the third April 17 and the last April 20.
If the remaining two eggs don't hatch, it could be a record low for the nest.
"I don't think we've ever had just one. Normally the low number has been two," Walters said.
He pointed out that a wet, cold spring is not good for bird eggs, and this season has been marked by erratic swings from hot to cold. Other factors contribute to the outcome, including the birds' health, their age and even pairing one of them could be a different bird than last year, when three eggs hatched.
But this mother and father, from what Walters has seen, "sure looked to me like ... they were on it. They seemed to be doing the job at hand. All of those things figure into a big question mark in my mind."
High-definition cameras set up in the nest give an online audience a front seat. It's upsetting to see the eggs fail, Walters said, but people should remember the eggs "are going to do what they're going to do. ... Let's focus on the living."
Walters expects the first chick to leave the nest sometime in early July.