The male Long-tailed Widowbird (Euplectes progne) has exceptionally long tail feathers roughly half a meter in length.
A study of the molecular phylogeny of bishops and widowbirds published in 2008 found that it formed part of a clade along with the Fire-fronted Bishop (E. diadematus), Black-winged Red Bishop (E. hordeaceus), Northern Red Bishop (E. franciscanus), Southern Red Bishop (E. orix), Zanzibar Red Bishop (E. nigroventris) and Red-collared Widowbird (E. ardens).