Birds can be a mixed blessing for farmers. Sometimes birds increase yields by gobbling crop-eating insects and rodents. But they may also devour crops, ingest beneficial bugs, or harbor pathogens that pose a risk to human health when they show up in food. “We really have to think of [birds] as a package deal, with all of the different ways that each species interacts with the farm,” says Elissa Olimpi, a conservation biologist at Virginia Tech. For two years, Olimpi spent her spring and summer mornings on strawberry farms, weighing that balance. The work—which involved carefully extracting birds from mist nets and placing them in cotton bags until they could be measured—was also a package deal. “It is really a special feeling to be up before sunrise, hearing birds and having a bird in your hand,” says Olimpi, who was at the University of California, Davis, at the time. But she also had to scoop up poop that birds left behind in the bags and freeze it for later...