Some scientists even wonder whether the recent decline in city noise could have unintended effects on bird behavior.

To compete with human-caused noise in urban areas, many birds have had to alter their songs as they struggle to be heard by potential mates, and some have even fled city life altogether. “As cities get quieter, it would be reasonable to imagine that we might see effects on birds’ willingness to sing or even on population densities,” said John Fitzpatrick, executive director of the Cornell Lab of Ornithology.

But, Dr. Fitzpatrick cautions, researchers still need hard data. Cornell’s scientists often look at data from eBird, an app for people to log bird sightings, which could help track any changes. In Europe, scientists recently launched a project called Silent Cities, asking volunteers to record urban landscapes, to study how wildlife sounds might shift during the pandemic.

If you go out looking for birds, remember that social distancing remains critically important during the coronavirus outbreak. That means it’s best to avoid parks when they’re crowded with other people. Fortunately, there’s still plenty to see and hear from an apartment window, backyard, or on a walk to the store.

David Lindo, a British birding expert known as the Urban Birder, has been staying inside in Mérida, Spain, for the past few weeks. But from his terrace, he’s already been able to spot 31 species, including a “gorgeous” flock of Eurasian spoonbills overhead and a family of house martins nesting on his balcony.

“You don’t need to be an expert to get started,” Mr. Lindo says. Smartphone apps like Merlin can help pick out birds in your area. Cornell’s researchers also developed an app, BirdNET, that identifies bird songs, but it’s available only on Android for now.

The best times to watch are early morning, when migratory birds land to stock up on food after traveling all night, as well as in the afternoon, when birds of prey hitch a ride on updrafts of warm air rising from the city.