Songbirds generally make their migratory flights at night, and during spring migration tens of millions of birds may be streaming north above us as we sleep. But when the sun rises, where do these tired birds choose to stop, rest, and refuel?

You may picture a nature preserve or grassy field, but a study published earlier this year in the journal Nature Cities shows that a large percentage of these birds are making their “stopovers” in cities, illustrating the importance of urban conservation efforts.