UC Berkeley's famous falcons are missing, researchers fear bird flu

BERKELEY, Calif. - A beloved celebrity couple, who was supposed to be making an appearance at UC Berkeley’s Campanile tower by this time of the year, has been missing. And there are fears they’ve been taken by the highly infectious bird flu.

The backstory:

Since 2017, Annie has perched herself atop the 307-foot Campanile for breeding season. 

A falcon named Archie assumed the role of her partner last season following Annie's loss of multiple mates, including her long-time partner Grinnell in 2022. Grinnell was found in the middle of the road in downtown Berkeley and had been struck by a vehicle.  

‘Elephant in the room’

On Monday, the Cal Falcons team posted its concerns about the missing birds, saying, "Neither Annie nor Archie has been seen at the Campanile since early January. This is the first time we've seen such an extended absence from the tower," the team wrote on social media, adding, "We have the elephant in the room: highly pathogenic avian influenza (HPAI)."

The team said peregrine falcons in the region can nest as late as May or June, so the window for breeding remained wide open. But they couldn't ignore the reality of the threat the birds faced amid the avian flu endemic in many bird populations.  

"Everybody is hoping for the best, but finally had to face that maybe they're not around, and so we talked about the possibilities with bird flu being probably the biggest issue right now," Cal Falcon raptor expert Mary Malec shared with KTVU on Tuesday.

Big picture view:

Malec said that the local peregrine population is down roughly 40%.

She said peregrines that have been found dead have been sent to the California Department of Fish and Wildlife for testing, which have all come back positive for bird flu.

"Avian flu kills very quickly within a day or two of ingesting something, and we know these birds hunt shore birds down by the bay. And bird flu is carried by ducks and in shore birds, so they're exposed quite a lot," Malec explained.

Researchers also said another indication that the bird flu endemic was affecting the peregrine population was that there has been a dramatic drop in floaters, or falcons that are looking for breeding territories. 

"We don't have the number of floaters that we usually have. You would expect in a place like the Campanile to have floaters,  just sitting around on the peripheries of the territory, ready to come in," Malec said. "We've seen a few, but not in the numbers that you would expect in a healthy population."

And the fact that both birds are missing ramps up the bird flu fears.

Other possibilities 

The Cal Falcon team noted there were other unfavorable outcomes to consider.    

"There are many predators out there, such as Great Horned Owls, or Bald and Golden Eagles, that will prey on a Peregrine when the opportunity presents itself," researchers wrote. "We have seen all of those large raptors in close proximity to the Campanile in the past, and we can't rule out the possibility that they have caused this disappearance."

And there's also the scenario that the birds were just taking their time.

"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," the experts said optimistically, also noting, "We've seen no evidence of a sick/dying bird at the tower, and the last time Annie and Archie were seen, both looked to be healthy." 

Other speculations about what could have happened included that the pair could be hunting somewhere off campus.

"We've seen Annie disappear from the Campanile before. If there are huge swaths of unoccupied hunting grounds out there due to HPAI, perhaps she's just off hunting in a new spot before returning to the Campanile for breeding," the team said.

The bird flu could also be affecting the falcons’ usual practices, though more of an unlikely case, according to the researchers. 

"It's possible that Annie and Archie are exploring different options for breeding," the team said. "Peregrine Falcons are often highly wedded to the territory location, but they do change spots if the nesting environment is not ideal." 

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And there’s the possibility that one of the two has died. 

Though if it's Archie that has died, it’s likely that Annie would not take long to find another mate.

"The peregrine tend to stay together for life, but if something happens to one of them, they're very pragmatic," Malec explained, adding, "After the first night Grinnell died, it took only seven hours for him to be replaced."

‘Wildly successful’ Annie

Historically, Annie has proven to be an exceptional falcon, outliving at least three mates, and she’s been extremely successful in breeding, hatching 22 chicks. 

"The average success rate in peregrines is about 1.1 chick per year. I calculated Annie's, and she's up to 2.75. So that's 2.5 times the peregrine average, so she's wildly successful," Malec said.

For now, the team and fans of Annie and Archie are holding vigil, many hopeful, others ready to accept the wild, unpredictable nature of nature. 

What they're saying:

"I hope your next report is Annie and Archie are fine - just OFF ON A 'VACAY' and an extended hunt. I hope they will return to the nest box when they're fat, happy and ready raise a new family," Bill Hill responded on Faceboook to the Cal Falcons' post. 

Chris Werme commented, "Those of us who have followed the Cal Falcons were starting to wonder where they were as spring approaches. It was time for an update. And since we were already aware of peregrines succumbing to avian flu, ignoring that possibility would have been irresponsible. I especially appreciate learning of the other possibility, that they could be relocating."

Whatever has happened, the Cal Falcon team promised to keep the birds’ fans abreast of what they know.

The only thing that can be confirmed is that, even with technologies like the live webcams that an allow up-close look at the birds' and their hatchlings' every move at their UC Berkeley home, researchers have limited access to the raptors' vast wildlife world.

"We are afforded only small snapshots into the cognition, decision-making, and lives of wild animals. Animals are complex," the researchers said. "Annie may have simply decided she no longer likes the taste of pigeon and wants to spice things up with some sandpipers. We may never know." 

Those who have been closely following the Cal Falcon group expressed their appreciation for the work the team does and their engagement with the public. 

Followers thanked the team for their informative, thoughtful, and detailed update.  

"People are sad, I think," Malec said. "Eventually, you know… if Annie's replaced by another female we’ll need to have some sort of memorial service for her, but we haven't really talked about when and how we'll do that."

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