Freshwater fish such as pike, carp, bream, perch, lamprey and trout were common. Trout, walleye, perch and catfish are common. Popular sport fish include walleye, perch, and northern pike. Northern pike, perch, and chub all can be caught on lampreys. They are the northern pike, roach, stone loach, European perch, and minnow. Leatherjackets feed on small fish including the silver perch. Ringed seals may also eat herring, smelt, whitefish, sculpin, perch, and crustaceans. This arrangement enables passerine birds to easily perch upright on branches. The streams held salmon, perch, and stickleback. Usually, the bird will perch to sing. They consume a wide range of prey usually caught by swooping down from a perch. They catch insects in flight, in sorties from an open perch. Owls hunt mainly by watching from a snag, pole or other high perch. Normally this owl hunts from a perch. Butterflies then land on the ground or on a perch to mate.