Annie, the peregrine falcon who has lived atop Berkeley's Campanile Tower for nine years, has been missing from her longtime roost for nearly two months, and falcon watchers fear the worst.

Annie the falcon and her mate of one year Archie have not been seen on the Campanile Tower since early January, as one observer noted on the Cal Falcons Facebook group Monday.

"This is the first time we've seen such an extended absence from the tower," the observer writes. "Although concerning, it is certainly possible that Annie and Archie may show up next month like nothing is different. Our typical first egg has been in mid-March, with Annie laying as late as the end of March."

They mention the "elephant in the room" is avian flu, which has been ravaging both wild and domesticated bird populations across the country, and they fear that both birds could have fallen victim to the virus.

The post mentions multiple other possibilities, including that the birds have just been off hunting or exploring new territory, and they may have relocated or they may suddenly return as they usually do.

"With substantial numbers of territories empty right now [due to avian flu], it's possible that Annie and Archie are exploring different options for breeding, maybe even looking for a different mate as pairs lose their partners," the observer writes. But, they add, this isn't a likely scenario given how wedding peregrines typically are to their territories.

Another possibility is that one or both of them were killed by a predator, like an owl.

"It is hard to potentially lose her, she's been a rock in the Berkeley community for so long," falcon expert Sean Peterson, Ph.D. tells ABC 7. Peterson seems to accept that avian flu is likely the cause of the birds' absence, but we may never know for sure.

Annie has been nesting atop the Campanile since 2016, spending her first five breeding seasons there with the same mate, Grinnell. He was tragically killed, either by a car or by crashing into the ground in downtown Berkeley in 2022.

Then, Annie entered her "telenovela" era, as Peterson describes it, immediately taking up with a new mate, Alden, who helped her incubate a clutch of eggs likely fathered that spring by Grinnell. Alden disappeared by the following year, and Annie took up with Lou, producing three new offspring. Then Lou ran off, and Annie took up last year with Archie, producing a clutch of four chicks for the first time.

Annie herself did a disappearing act in February 2022, going absent from the Campanile for several weeks and prompting fears she was dead or injured, only to suddenly reappear in early March. So, anything remains possible.

If Annie is indeed gone, she had a remarkably successful stretch in Berkeley, giving birth to 22 chicks since her arrival there. And the falcon-watching community will now just have to hope that a different peregrine pair — perhaps including one of Annie's offspring! — decides to move into the vacant tower nest.

"We'll get a whole new season as it [were], a new cast of characters," Peterson tells ABC 7.

Previously: Runt of Berkeley Falcon Brood Dies Three Months After Injuring Wing

Photo via Cal Falcons