For more than 40 years I've thought that this time of year is a special one to enjoy the red, yellow and orange autumn of not just aspen and maples but also poison ivy foliage.

Although people fail to find anything interesting about this 1- to 2-foot-tall common shrub in the Upper Midwest (that can cause serious skin irritations), they often want to know how to control or get rid of the plant. As a naturalist and outdoor educator I have taught numerous school kids and adults how to identify poison ivy and to appreciate its use as a native ground cover and food for wildlife.

At least 59 species of birds — gray catbirds, northern flickers, white-throated sparrows, sharp-tailed grouse, ring-necked pheasants, and wild turkeys among them — feed on the berries, often in winter when other foods are scarce. After eating the berries, the birds spread the seeds over large areas. In addition, the leaves, stems and berries are food for bears, deer and cottontail rabbits.

Poison ivy can be found in dry fields, pastures, rocky exposures, on river and lake banks, and along fence rows and roadsides. The green leaves (some glossy, some dull) on the woody stems are divided into three leaflets. Each are about 4 inches long. The center leaflet has a longer stalk than the two lateral leaflets. Small yellow-green flowers appear in June but pass almost unnoticed. The grayish-white fruits, up to a quarter inch in diameter, appear in clusters and persist through winter.

A more accurate name for poison ivy might be "allergic ivy." Itching areas and runny blisters of the skin are the allergic response to poison ivy's plant oils. The resin ducts of roots, stems, leaves, flowers and fruits contain oils that cause the rash. They always are active.

Jim Gilbert taught and worked as a naturalist for 50 years.