Gnatcatchers are a group of small insectivorous passerine birds. The family Sylviidae is a group of small insectivorous passerine birds. Starlings are small to medium-sized passerine birds. Old World sparrows are a family of small passerine birds. Toucans are near passerine birds from the Neotropics. The common starling is mid-sized by both starling standards and passerine standards. Emberizidae is a family of passerine birds containing a single genus. Todies are a group of small near passerine forest species endemic to the Caribbean. There is large variation of sperm length in passerine birds. The leg of passerine birds contains an additional special adaptation for perching. As with other passerine birds, parasites are common. The bowerbirds are small to medium-sized passerine birds. The emberizids are a large family of passerine birds. Taurine appears essential to the development of passerine birds. The cuckooshrikes are small to medium-sized passerine birds.