Eastern Air Lines began passenger service, flying Kingbirds and Condors. Tyrannus is a genus of large insect-eating birds, commonly known as kingbirds. The majority are named as kingbirds. Like other kingbirds, they are very aggressive in defending their nest. Some eastern kingbirds place their nests in the open, while others hide their nests well. Kingbirds attack other birds that come too close. Kingbirds are birds of the genus "Tyrannus" in the tyrant flycatcher family.