Eurasian eagle-owl
In the lower Himalayas of northern Pakistan and Jammu and Kashmir, along with the brown fish owl, the Eurasian eagle-owl at the limit of its distribution may co-exist with at least two to three other eagle-owls. One of these, the dusky eagle-owl ("B. coromandus") is smaller, with more uniform tan-brownish plumage, untidy uniform light streaking rather than the Eurasian’s dark streaking below and an even less well-defined facial disc. The dusky is usually found in slightly more enclosed woodland areas than Eurasian eagle-owls. Another is possibly the spot-bellied eagle-owl ("Bubo nipalensis"), which is strikingly different looking, with stark brown plumage, rather than the warm hues typical of the Eurasian, bold spotting on a whitish background on the belly, and somewhat askew ear tufts that are bold white with light brown crossbars on the front. It is possible that both species occur in some parts of the Himalayan foothills but they are not currently verified to occur in the same area, in part because of the spot-bellied’s preference for dense, primary forest. Most similar, with basically the same habitat preferences and the only one verified to co-occur with the Eurasian eagle-owls of the race "B. b. turcomanus" in Kashmir is the Indian eagle-owl ("B. bengalensis"). The Indian species is smaller with a bolder blackish facial disc border, more rounded and relatively smaller wings and partially unfeathered toes. Far to the west, the pharaoh eagle-owl ("B. ascalaphus") also seemingly overlaps in range with the Eurasian, in at least the country of Jordan. Although also relatively similar to the Eurasian eagle-owl, the pharaoh is distinguished by its smaller size, paler, more washed-out plumage and the diminished size of its ear-tufts.
Dietary biology of the Eurasian eagle-owl
Jirds, jerboas, gerbils and hamsters, particular the genera "Allactaga", "Ellobius", "Gerbillus", "Meriones", and "Pygeretmus", start to become noticeable in the diet in the more arid portions of this species’ range, i.e. from Asia Minor to the Middle East and Central Asia. Relatively large species such as Tristram's jird ("Meriones tristrami") and the Euphrates jerboa ("Allactaga euphratica") are often amongst the more prominent species to be hunted. In western Kazakhstan, the primary foods are the great jerboa ("Allactaga major") and northern mole vole ("Ellobius talpinus") while on the Buzachi and Mangyshlak Peninsulas of the Kazakh Caspian Sea, the primary foods were the Libyan jird ("Meriones libycus"), great gerbil ("Rhombomys opimus") and small five-toed jerboa ("Allactaga elater"). All told, in the peninsular Kazakh regions of the Caspian Sea, jirds, jerboas and gerbils made up about 92% of the food. In the Tibetan Plateau of China, the tundra vole ("Microtus oeconomus") is the leading prey species, making up 53.1% of the prey. In Mongolia, two rather small rodents, the Mongolian five-toed jerboa ("Allactaga sibirica"), at 23.6% of the prey, and the Campbell's dwarf hamster ("Phodopus campbelli"), at 14.5% of the prey, make up a majority of the prey by number. In the Transbaikal, the Chinese striped hamster ("Cricetulus barabensis") was the main prey species, making up 43.8% of the diet.
What all primary rodent prey species share is that they are either nocturnal or crepuscular and are often common to abundant in openings of woods and rocky environments. The reason Eurasian eagle-owls take rats, which associate rather closely with humans, much more regularly than they take house mice ("Mus musculus") is not their larger size (many other rodents regularly taken by eagle-owls are as small or smaller than a house mouse) but the rat's ability to flourish along the edges of crop fields, refuse dumps, roadsides and abandoned buildings and fields, whereas the mice are more closely tied to active human habitations. A single refuse dump can host several thousand rats and eagle-owl territories that include dumps can locally expect higher productivity due to the abundance of this food source. Squirrels are readily predated but, being diurnal, are largely unavailable to this and other owls. When they are captured, it is presumably around dawn or dusk from their tree hole, in species such as the widespread red squirrel ("Sciurus vulgaris"), or burrow entrance, in the case of ground squirrels, most regularly recorded as prey in Asia Minor and the Central Asia. A few specimens of the woolly flying squirrels ("Eupetaurus cinereus"), the largest of the world's flying squirrels and one of the rarest, were the only identified foods for Eurasian eagle-owls in northern Pakistan alongside some European hares. Although not common in the diet, a few species of marmot have been taken and may be an important aspect of the prey biomass. In Europe, adult-sized alpine marmots, ("Marmota marmota") have been killed. However, the average weight of Tarbagan marmots ("Marmota sibirica") taken in Mongolia was only and that of alpine marmots in Engadin, Switzerland was only . These obviously comprising young marmots as adults have average weights from , from spring low weights to pre-hibernation weights during autumn hypophagia. Other than marmots, the largest rodent known to be hunted by Eurasian eagle-owls is the introduced aquatic rodents, the muskrat ("Ondatra zibethica"), which in one study estimated to average when taken, and the nutria ("Myocastor coypus"), equal in size to the large marmots.