Winterberry (Ilex verticillata) is a deciduous shrub native to eastern North America, particularly in swampy areas. This makes it a great plant for those moist areas in your landscape, tolerating poorly drained soils. It will need acidic soil and a full sun to part shade site.
Mostly known for its bright red berries, you will need at least one male plant for every 6-10 female plants for adequate pollination and berry production. Many cultivars are available, but the straight species may be found at specialty native plant nurseries. Most cultivars have been bred for smaller size and increased berry production. I would avoid any cultivars that have orange or white berries, as these are likely not as preferred by birds as the red berries are.
Winterberry provides great winter interest in the garden - plant it where the berries will stand out such as in front of evergreens. Here in South Central PA, Ilex (holly) species are host plants to at least 44 species of moth and butterfly caterpillars. Seeing some bites taken out of the leaves is a good thing!
Sources: National Wildlife Federation, USDA, Missouri Botanical Garden