The Eurasian (or Northern) Sparrowhawk (Accipiter nisus) is a small bird of prey in the family Accipitridae which includes many other diurnal raptors such as eagles, buzzards, harriers, and other sparrowhawks. Adult male Eurasian Sparrowhawks have bluish grey upperparts and orange-barred underparts; females and juveniles are brown above with brown bars below. The male is up to 25% smaller than the female – one of the largest differences between the sexes in any bird species.
Considered by many to be the one of the most difficult birds to train and fly successfully. The reason for this is that even the females weigh only around 7 to 9 ounces, the males around 4 ounces. With such a small bird, getting the hunting weight correct for successful hawking is very difficult. The accuracy of weight control needed to get the best from these birds is best left to those who have trained and flown other less difficulty species for a few seasons first.