Bittersweet (Celastrus sp.) is one of the last splashes of color left in the woods this time of year. There are two types found locally. One, unfortunately the more common, Oriental bittersweet, is an invader, pushing out the native American bittersweet. Worse, it seems that the two can interbreed, making removal of unwanted bittersweet an identification nightmare. Read more here.
Putting the potential problems aside, bittersweet is an interesting and pretty plant. It vines in spirals (sometimes strangling trees), and provides the very last food for birds before spring. Our common winter birds, like the mocking bird and the European starling (another prolific invader), can often be seen among the vines, eating the fruit. When one examines the droppings left behind, one can see the orange skin of the fruit and the seeds. Both are nearly indigestible; the fruit itself has little nutritional value since it is mostly seed and skin, but what little it has to offer is welcomed by the very hungry birds in late winter. The seeds are spread by the birds (and foxes, I bet) in their droppings.
The kids entertain the rather dangerous habit of swinging on bittersweet vines when we hike. Since the vine does damage trees, this sort of play makes me a bit nervous. I have seen large vines come tumbling down out of the high branches, sometimes taking a tree branch or two with it. Have a care if you have young Tarzans on your hike! See a strangling vine photo here.
It often vines along with other climbing plants. Try your identification skills out when you see a mixed tangle. In this area (NY), you might find grapevine, poison ivy, cat briar, and Virginia creeper, near the bittersweet. Can you tell which is which in the winter?