Standing in a northern Everglades marsh in 2015, biologist Corey Callaghan watched as an enormous flock of tree swallows wheeled in the morning sun. As the mass of birds passed overhead, Callaghan and ...

Our top tried-and-tested picks for birdwatching, stargazing or observing wildlife — find the best models ahead of Black Friday. When you purchase through links on our site, we may earn an affiliate ...