The National Aviary, which runs a livestream camera of the nest, says parents Carla and Ecco laid four eggs this season. The first egg hatched on Friday evening and the eggs continued to hatch through Monday, with the final chick breaking into the world around 1 p.m.

The aviary says this will be Carla and Ecco’s first attempt at being parents to a brood of four. The birds will grow up fast and fledge the nest about 40 days after hatching. After they fledge, the aviary says they’ll stick around for part of the summer, learning how to hunt from their parents. Once they’ve figured that out, they’ll strike out on their own. 

The birth of these chicks is good news for Allegheny County’s peregrine falcon population. Volunteers counted a record number of six peregrine falcons during the annual Audubon Christmas Bird Count. 

The county’s current peregrine falcon population is a big bounce back from the early 1960s, when the use of DDT meant there were no peregrine falcons nesting in Pennsylvania. After the harmful pesticide was banned in 1972, conservation efforts have helped the species rebound. 

Scientists now monitor the species’ population through citizen science projects like the Christmas Bird Count and by banding the chicks. Last year, the Pennsylvania Game Commission banded three chicks born in the nest on Pitt’s Cathedral of Learning, and the year before that, two chicks were banded.