North America has more species of owl than Europe and can be considered a more competitive environment for long-eared owls living there. However, again, in most cases habitat preferences, slight partitioning in dietary preferences (which may be in prey species or body sizes of prey selected) and life histories generally allow most species to persist even when living in proximity to one another. As throughout their range, long-eared owls tend to differ from most other North American owls by being much more migratory in nature. Therefore, cyclic food variations affect them differently and are less likely to be the direct cause of winter mortality than in more permanently residential owls. Oddly enough, among American owls, long-eared owls most strongly mirror the much smaller northern saw-whet owl in distribution, migratory habits and, to a lesser extent, food habits. The main food of saw-whet owls tends to be "Peromyscus" mice where they are available and, like most owls, their rodent food selection can broadly overlap with that of long-eared owls. It has been posited that the less broadly ranging occurrence of long-eared owls in general compared to in their European range is in part due to greater resource competition between them and the two widespread screech owls, the eastern ("Megascops asio") and western screech owls ("Megascops kennicotti"). However, the feeding niche tends to be much wider and more opportunistic in screech owls, which often feed on a diversity of invertebrates (mainly insects but also crayfish) and alternate prey (a higher balance of birds and frogs, for instance) and so are unlikely to competitively limit rodent numbers to the detriment of long-eared owls.