Many kinds of insects feed on various parts of River Birch and other Betula spp. (birch trees), especially the caterpillars of many moths (see Moth Table). Other insect feeders include the caterpillars of the butterfly Nymphalis antiopa (Mourning Cloak), the larvae of sawflies, the grubs of wood-boring beetles, leaf beetles, plant bugs, shield bugs, leafhoppers (Oncopsis spp.), aphids, and others (see Insect Table for a listing of these species). Among vertebrate animals, some species of birds eat the seeds, buds, or catkins of birch trees; these species include the Ruffed Grouse, Greater Prairie Chicken, Passenger Pigeon (now extinct), Pine Siskin, White-Winged Crossbill, Purple Finch, and Black-Capped Chickadee. The seeds are also eaten by the Red Squirrel. Beavers feed on the wood and bark of River Birch, and they use its branches in the construction of their dams and lodges. White-Tailed Deer browse on the twigs and foliage, while the Cottontail Rabbit gnaws on the bark of saplings and browses on the twigs and foliage of seedlings.