Species richness of Tyrannidae, when compared to habitat, is highly variable, although most every land habitat in the Americas has at least some of these birds. The habitats of tropical lowland evergreen forest and montane evergreen forest have the highest single site species diversity while many habitats including rivers, palm forest, white sand forest, tropical deciduous forest edge, southern temperate forest, southern temperate forest edge, semi-humid/humid montane scrub, and northern temperate grassland have the lowest single species diversity. The variation between the highest and the lowest is extreme; ninety species can be found in the tropical lowland evergreen forests while the number of species that can be found in the habitats listed above typically are in the single digits. This may be due in part to the fewer niches found in certain areas and therefore fewer places for the species to occupy.