in size from azure-winged magpies (Cyanopica cyanus), at , to carrion crows (Corvus corone), at , but usually turn up in low numbers in dietary studies and these owls are far less prolific corvid hunters than some diurnal predators such as Accipiters.Griesser, M., & Ekman, J. (2005). Nepotistic mobbing behaviour in the Siberian jay, Perisoreus infaustus. Animal Behaviour, 69(2), 345-352. Other than pigeons and doves, non-passerine bird prey are usually taken relatively infrequently, although some prey families such as gamebirds and woodpeckers are also quite widely taken. An unusual preference for relatively large bird prey was reported in study from the Urals where the most frequently identified avian prey species were the hazel grouse (Bonasa bonasia) and the hooded crow (Corvus cornix). On infrequent occasions, Ural owls may be able to overtake bird prey of up to approximately their own size or somewhat larger, i.e. up to or slightly over in average body mass, such as adult mallard (Anas platyrhynchos), common goldeneye (Bucephala clangula), black grouse (Tetrao tetrix), common pheasant (Phasianus colchicus), chicken (Gallus gallus domesticus), black-crowned night-heron (Nycticorax nycticorax) and some accipitrids as well as, so far as is known, only young specimens of the larger still western capercaillie (Tetrao urogallus).Saniga, M. (2002). Nest loss and chick mortality in capercaillie (Tetrao urogallus) and hazel grouse (Bonasa bonasia) in West Carpathians. FOLIA ZOOLOGICA-PRAHA-, 51(3), 205-214. Outside of aforementioned families other infrequently taken bird prey has included cuckoos, nightjars, sandpipers, terns, rollers and hoopoes. Due likely in no small part to the scarcity of herpetological prey diversity in the temperate and often frigid haunts of Ural owls, reptiles are very infrequent prey for this species. However, sometimes frogs may be taken when an Ural owl opportunes upon one in the warmer months of the year. Usually, in nearly any part of the range, frogs and other amphibians constitute less than 6% of the regional diets for the species.Mikkola, H. (1970). On the food of great grey owl (Strix nebulosa), the Ural owl (Strix uralensis) and the eagle owl (Bubo bubo) in Finland during summer. Suomen Riista, 22, 97-104. In the small Swedish study from Värmland County, an exceptional 12.2% of delivered prey was common frogs (Rana temporaria). In spite of historic records of fish scales being found seldom in some pellets, there is no known reportage of confirmed predation on fish by Ural owls in dietary studies. There is little evidence