each night as the sun sinks, thousands of crows descend on sunnyvale, california. the birds overwhelm the downtown, raising a ruckus as they alight in tree tops to roost for the night. though welcomed by some, the daily spectacle has become a source of frustration for many of the city’s business owners and locals. 

“the crows are very noisy, and their droppings and feathers have created quite a mess,” says jennifer garnett, sunnyvale’s communications officer. “our council members have received many complaints from residents and businesses. we also have had to increase our frequency of pressure washing both areas.” 

most of the birds gather at sunnyvale’s plaza de sol, an open area bordered by trees and mixed-use buildings at the heart of the city. the 1.6-acre urban oasis boasts an amphitheater for summer outdoor concerts and sits adjacent to historic murphy avenue—a tree-lined street that hosts many restaurants and businesses. the plaza has always attracted crows, but the pandemic-fueled increase in outdoor dining—and the food scraps that comes with it—led to record numbers, garnett says. 

in an unsuccessful attempt to deter the birds, the town first tried hazing them with trained hawks and falcons. reflectors meant to confuse the flocks have also seen limited success. so, last month, sunnyvale turned to a $20 tool found at any office: a laser pointer. every weeknight for three weeks, beginning in later january, a trained city employee wielded a handheld green laser purchased on amazon. for 30 minutes at dusk, the staff person would shine the laser pointer into the plaza treeline where crows are beginning to settle in for the evening. the goal was to startle them each night until they eventually scatter for good. 

so far, sunnyvale is seeing success. “the laser pointer does seem to be working, “ garnett says. “however, we know that the crows are very smart and are likely to return when the deterrent goes away.” sunnyvale ceased the pilot program the week of february 14 and has not said whether it will resume the initiative if the birds return. 

sunnyvale is not alone in its corvid conundrum. urban populations of crows have been increasing in recent decades, and as a result, more cities and towns have tried to discourage them and other prolific species like canada geese using a variety of methods, including lasers. green has been found to be most effective laser color for evening hours—the light scatters in the atmosphere and produces a stronger beam that is more visible in the sky. the beams are also considered to be a safe deterrent. a 2002 study conducted by the u.s. department of agriculture’s national wildlife research center found that low-to-moderate power, long wavelength lasers can disperse birds in low-light conditions while presenting “no threat to the animal or the environment.” 

green lasers create “flashing movements” that are foreign to crows’ natural environment, says kevin mcgowan, instructor and crow expert at the cornell lab of ornithology. “there’s nothing magic about lasers, just that the small tool has an effect across a great distance.” lasers also aren’t a one-and-done solution, mcgowan says, noting that the approach isn’t foolproof and works best in combination with other hazing methods.

timing can be important for success, experts say. 

as an example, he points to several cities in new york that have had varying success with lasers. in 2005, auburn spent $14,000 on a hazing program spearheaded by the united states department of agriculture’s wildlife services. at the time, auburn’s crow population of roughly 64,000 birds outnumbered humans more than two-to-one. a mixed-use approach of lasers, pyrotechnics, and speakers blasting recordings of calls from distressed crows drove almost half of the population out of the city in just one week. yet, many simply relocated to nearby cortland or geneva. and 17 years later, auburn’s crow problem persists to enough of a degree that local artists recently embraced the city’s divisive mascot with fluorescent mosaics.

timing can be important for success, experts say. lasers are most effective at the beginning of the winter season, within a few days of the crows’ establishment, says john griffin, senior director, urban wildlife programs at the humane society of the united states. crows are intelligent creatures, and griffin notes that it gets “harder [to drive them away] the longer they’re there.” by the time spring rolls around, the birds will migrate elsewhere—but many return to the same city blocks winter after winter, only growing in numbers.

even if cities like sunnyvale manage to temporarily drive out downtown roosts, the crows will likely return unless they can find another suitable habitat. for this reason, matthew dodder, executive director of the santa clara valley audubon society, thinks that the best solution in sunnyvale is to learn to live with the birds. “from my point of view, it seems like not much can be done to change the situation,” he says. “so we should adapt to accept it, and appreciate it, and work around it.” dodder offers up ideas like covering dining areas and being better about trash management to help mitigate the impacts of the birds around the plaza. 

bigger picture, dodder hopes to see more changes in the development of urban and suburban spaces that would contribute to a more harmonious coexistence between bird and man. “if we can create new green spaces, that might just work,” he says. mcgowan agrees, recalling that he and his colleagues considered creating a designated “crow oasis” for the auburn flocks decades ago. but the city stuck to its ongoing hazing strategy instead.

another solution is cultural—teaching people to appreciate crows and other urban birds. instead of finding large flocks creepy or annoying, mcgowan says, we should see them as fascinating examples of species adaptation in an age where even the most common species are disappearing. “they’ve been doing this for thousands of years,” he says. “it’s actually a spectacle.” 

lips was camped out in the costa rica rainforest, alone, for a year and a half. her shack was nestled in a remote village atop a mountain bordering panama. each night, she plucked every frog she spotted up from the jungle’s tapestry of flora and swabbed them. 

“you’re walking down this beautiful trail, and you hear the birds and see a hummingbird sleeping on the branches. and you look up and there’s a frog sitting on a leaf, and you walk over there, and you pluck it off the leaf,” lips says.

that was in 1993. when lips returned just three years later, she couldn’t hear the croaking of toads or frogs splashing in streams. their environment was “dead silent.” lips noticed that the number of frogs in the region was  down 90% by 1996. initially, lips blamed everything, from her headlamp to the weather. but when she spotted dead frogs everywhere, she sensed she was front-row to the world’s next environmental calamity.

lips shipped 50 lifeless frogs back to a veterinary pathologist in maryland who confirmed her greatest fear… thousands of frogs were dying at the hands of a mysterious killer. 

a viral villain

it wasn’t until the late 1990s when researchers like lips discovered that frogs in australia and panama were dying by the masses. the silent killer wasn’t an elusive predator or a toxic food source. rather, a virulent fungus was swiftly eradicating species in one fell swoop. amphibians were dying at the hand of batrachochytrium dendrobatidis.

the fungus—called bd for short—is so lethal because it invades amphibians’ porous skin, which the animals use to breathe and drink water. the viral villain destroys the skin’s proteins and devours the remaining amino acids. infected animals become lethargic and experience organ failure in a matter of weeks.  

like the most vicious of diseases, bd doesn’t play favorites: it annihilates frogs young and old, wiping out amphibians across the globe. some amphibians can resist or tolerate bd, but 695 species are vulnerable. and 90 species already have disappeared, while 500 others have sunk into a steep decline, with few projected to recover.

“it’s so widespread. it’s not specialized or anything. it’s huge, it’s just a terrible generalist disease. and that’s what makes it terribly lethal,” lips says.

stopping bd’s killing spree

after her bombshell discovery, lips dove headfirst into understanding and advocating for “one of the largest losses of biodiversity.” in the 25 years since, bd’s killing spree hasn’t slowed down, and neither has lips. 

“there’s so many ways to think about karen and all the different things she’s done. i think one is her curiosity, and her ability to just persist, that she cared so much about this,” says margaret krebs, who led a leadership academy with lips.

lips tracked the global spread across six continents to find that human activity is pushing an amphibian death wish to all corners of the earth. the amphibian meat and pet industries allow bd to travel, leaping off of the back of one frog to the next.

though the virus poses no direct health threat to humans, the global destruction of frogs has devastating consequences. a decrease in the frog population causes an uptick in insects like flies and mosquitoes, who spread deadly diseases including malaria and pose a danger to human health. 

“there are indirect effects on human health… as soon as the frogs disappeared, there’s about a 10-year increase in the number of malaria cases in costa rica and panama,” lips says.

currently, wild populations raging with bd cannot be cured on a global scale. for now, researchers say that the best step is to prevent the fungi’s further spread. in 2009, lips left the south american rainforest for the bureaucratic jungle to promote policy that would prevent the further spread of bd.

“because she saw her study and research sites destroyed by this disease, she realized she was going to have to jump in and get her hands dirty in the policy world to try to deal with it,” says peter jenkins, an environmental lawyer who petitioned government agencies alongside lips for preventing the import of infected amphibians who might bring bd. 

bd is already present in the united states, and the u.s. fish and wildlife service is actively monitoring its spread. yet, in march 2017, the agency ceased consideration of a 2009 petition to ban all amphibian imports unless they were bd-free. 

lips argues that although bd is already in the united states, other harmful variants could make their way into the country without the proper testing that is not presently in place. studies show that the even deadlier african and brazilian strains of bd could hybridize with the original bd strain. 

in 2013, researchers identified b. salamandrivorans, known as bsal. its name aptly translates to “salamander-devouring,” as from 2009 to 2012 the fungus eliminated dutch fire salamander populations by more than 99%. a 2016 ruling banned the import of 201 salamander species. however, if the bsal-infected species were already in the u.s. before the ban went into effect, interstate transport of the species is legal. 

salamanders are indicator species, the frontline voice to determine if an environmental catastrophe is looming. often referred to as a “canary in a coal mine,” they serve as an early warning system for an ecological decline that will inevitably impact humans. spotting a two-lined salamander living under a rock at a stream is a sign of good water quality. the absence of woodland salamanders in a forest is an ill omen.

“(north america) has more families, more species of salamanders than anywhere else in the world. we safeguard the salamanders of the planet,” lips says. “and so if this salamander chytrid gets here, we’re going to expect to see massive infections, die-offs, and impacts just like we saw with bd.”