Dietary biology of the Eurasian eagle-owl but none are heavier than the largest mammalian prey that eagle-owls have taken including greater white-fronted goose ("Anser albifrons"), bar-headed goose ("Anser indicus"), great cormorant ("Phalacrocorax carbo"), Himalayan snowcock ("Tetraogallus himalayensis") and demoiselle crane ("Anthropoides virgo"), all averaging around , the swan goose ("Anser cygnoides"), the common crane ("Grus grus") and the (between the dimorphic sexes) great bustard ("Otis tarda"). Eurasian eagle-owls have also hunted adult male western capercaillie, which average about , although usually the much smaller females, at , are more regularly taken. Although they rarely take domestic birds, the range of sizes killed is just as dramatic,
Xylota tarda Xylota tarda Xylota tarda is a Palearctic species of hoverfly. External images For terms see Morphology of Diptera<br> Wing length 5·5-8·5 mm. Large red areas on black abdomen. Wing membrane not infuscated. Dorso-apical white bristle on metatarsus 1. Antero-dorsal pale hairs on the basal half of femur 3 uniform not longer than 1/4 the depth of femur. The male genitalia are figured by Hippa (1968). The larva is illustrated in colour by Rotheray (1994) ). See references for determination (but see Speight for contradiction) Palearctic Fennoscandia South to Spain. Northern Italy (Apennines) Slovenia. Ireland East through Central Europe into European