Ural owl
The tawny owl is thought to be a close relative of the Ural owl. Authors have hypothesized that the origin of the species divide followed Pleistocene continental glaciations segregated a southwest or southern group in temperate forest (i.e. the tawny) from an eastern one inhabiting cold, boreal ranges (i.e. the Ural). The species pattern is mirrored in other bird species, i.e. the European green woodpecker ("Picus viridus") from the more northern transcontinental grey-headed woodpecker ("Picus canus"). After retreat of the continental ice masses, the ranges more recently penetrated each other. While the life history details of the tawny and Ural owls are largely corresponding, nonetheless the species have a number of morphological differences and are largely adapted to different climates, times of activity and habitats. Based on "Strix" fossil species from Middle Pleistocene (given the name "Strix intermedia") in variously the Czech Republic, Austria and Hungary show from leg and wing bones indicate an animal of intermediate form and size between Ural and tawny owls. However, fossils of a larger and differently proportioned "Strix" owl than a tawny owl, identified as "Strix brevis", from Germany and Hungary from before the Pleistocene (i.e. Piacenzian) and as well as diagnosed Ural owl fossils from disparate southerly deposits in Sardinia from the Early Pleistocene and in Middle Pleistocene deposits in the Pannonian Basin as well as much later during the early Holocene from far to the west in Belgium, France and Switzerland suggest a more complicated evolutionary and distributional history. A hybrid was recorded in captivity between a male Ural and a female tawny owl, which managed to produce two offspring that were intermediate in size and had a more complex song that was also shared some characteristics with both species’ vocalizations.