SAN FRANCISCO

A peregrine falcon whose longtime companion died this week in the middle of the breeding season appears to have found a new partner to help hatch two eggs.

Grinnell, one of two beloved peregrine falcons who have long made their home atop the steeple of the University of California, Berkeley, was found dead on Thursday. Less than 24 hours later, her partner Annie had mated with a new, untagged male falcon, Cal Falcons, a group that monitors birds, said on Twitter on Friday.

“When a married peregrine dies during breeding season, the most likely outcome of the nest is abandonment,” Cal Falcons tweeted. “In rare cases, a new mate may enter, bond with the remaining individual, and adopt the chicks.”

While peregrine falcons usually mate for life, those that lose a mate will seek a replacement after a mate dies.

The new falcon also seemed interested in incubating Annie’s eggs and performed several courtship displays with Annie after spending the night in her gravel nest, the group said.

“Although these two eggs may still not survive, this is an encouraging development,” they said. “We will be keeping an eye on prey deliveries and incubation in particular, as both of these behaviors will be an indication of a potentially successful nest.”

Grinnell was found dead on a street and was likely hit by a car, the group said. Grinnell and Annie have been nesting atop the university’s 307-foot-tall Campanile since late 2016 and have produced 13 chicks.

Grinnell was attacked by other hawks last fall and spent nearly three weeks recovering in a wildlife hospital, while other rivals courted Annie. But he returned, and observers felt the couple were getting closer.

Hours before his death, Grinnell was seen defending the nest against another peregrine falcon. Cal Falcons said it’s possible the new falcon is the one Grinnell fought, although an injury to the bird’s left foot appears to be older.

In February, Annie disappeared from her nest and was briefly presumed injured or dead before returning nearly a week later. His disappearance made local headlines.

Falcon researchers said they have never seen a female suddenly disappear during peak breeding season and then suddenly return.

Peregrine falcons are considered the fastest birds in the world. They can reach 200 miles per hour (322 kilometers per hour) on a hunting dive known as a stoop. American birds were declared endangered in 1970 due to ingestion of prey poisoned with DDT and other pesticides. The chemical caused the hawks to produce thin-shelled eggs that could not survive to hatch. However, recovery programs have brought the bird back from potential extinction.