That evening I did a little research and found it’s also called “black alder” and “fever bush.” The National Audubon Society’s Field Guide to Wildflowers, Eastern Region, says,
This shrub is extremely showy in late fall and early winter, when covered with bright fruits. Birds are readily attracted to them.Well, that sounds good to me! I garden for the birds all the time and am always looking for new plants. My native red mulberry trees are amazing, especially when dripping with Cedar Waxwings. In the summer, I love it when I’m outside and first hear their twittery call. All I have to do is look up into the mulberry and there they are. But the nice thing about winterberry hollies is even if the birds decide to pass them by, they are stunning in the drab, winter landscape. Some references indicate winterberries are often used by birds only as emergency food sources, and that is good too.
Winterberry holly is native to eastern Canada and the eastern half of the Unite States. It likes a wet foot, so if you have swampy area in your yard (which I do), you’re set. Winterberry holly is dioecious, so you need to buy at least one male plant and one female plant to obtain the beautiful red berries. In the photo, you’ll notice it sheds its leaves in the fall. Being deciduous is part of its charm, because the berries are all the more noticeable.
An interesting tidbit, the common name "fever bush," comes from the fact that native Americans (of eastern North America) used winterberry to reduce fever.