Poison Ivy, Toxicodendron radicans, this “leaves of three- let it be” is also prime example of the general rule to avoid eating white berries. You should probably avoid everything else about this plant as well. Many people have allergic reactions from urushiol, the toxin contained in the oil from the leaves, stems and roots. It creates a reaction from a mild rash to a severe condition demanding medical attention. This is a plant you should respect, and probably avoid until you know your tolerances.
Downy Woodpeckers adore poison ivy berries.
However, as loathed as is it by some people, it does have a valuable place in nature’s landscape. It is a primary food source in the winter months, and birders may note it's especially attractive to woodpeckers. So before you totally write this one off as a plant only Cruella De Vil would harbor, remember there is place in nature for plants we may not seek to cultivate at home.