Peregrine falcon pair on Pitt's Cathedral of Learning lay first egg of season

The peregrine falcon pair in the nest on top of Pitt's Cathedral of Learning have laid their first egg of the season.

The National Aviary says Carla laid an egg around 1:17 p.m. on Sunday. It's the first of up to four that Carla and Ecco could lay this year, though sometimes there can be as many as six eggs in a peregrine falcon clutch.

Carla will now likely lay an egg every 48 hours until her clutch is complete. She won't start incubating until all her eggs are laid, doing about two-thirds of the work while Ecco takes over the rest of the time. The aviary says it's perfectly safe for the eggs to be left uncovered because they have strong temperature tolerances and can endure Pittsburgh's rollercoaster springs. 

Last season was Carla and Ecco's first together, and there was plenty of excitement. While eggs usually hatch two to three days apart, two chicks hatched, fittingly, on Earth Day. They laid a total of four eggs, though one failed to hatch and the third chick died. 

Peregrine falcons used to be endangered in Pennsylvania because of the use of the pesticide DDT, but they were removed from the state's threatened and endangered species list in 2021, the Game Commission says.   

Last year, the Game Commission placed lightweight bands with identifying numbers on the chicks' legs, which will help scientists study the behavior of peregrine falcons while also keeping an eye on the status of their population. 

The aviary's FalconCam livestreams the nest, which is high up on the southeast side of Pitt's Cathedral of Learning. Viewers can watch Carla and Ecco's family grow this year on the aviary's website.