If you are fortunate enough to have an American holly (Ilex opaca) growing in your yard, you might wonder if this tree really does live up to its reputation of being an outstanding wildlife food plant. This is because countless bright red berries can still be seen hanging among the thorny leaves of this native evergreen. It seems as if birds and other wildlife simply do not eat them.
The truth of the matter is the tree’s berries are eaten by a variety of birds. In fact, they are considered an important source of food for a long list of birds that includes, but is not limited to, the eastern bluebird, yellow-bellied sapsucker, cedar waxwing, American robin, northern mockingbird, northern flicker, and northern cardinal.
The reason these berries are often seen on a holly tree in early January is, in order for the berries to be more palatable to birds and other wildlife, they have to go through a number of freeze-thaw cycles. This helps guarantee that birds and other wildlife will have a source of food well after many berries and seeds have disappeared.
Since this is the case, late in the winter or early spring, it is not uncommon for a flock of robins, cedar waxwings or other birds to devour all of the berries found on a small holly tree in a single morning or afternoon.