Deer eat a lot! As they feed, they can affect plants, animals and even insects. Deer like some plants more than others, which can lead to fewer plant species in your woods. Lilies, for example, can be eliminated when deer feed on them repeatedly. Studies in northern Wisconsin have shown that deer can keep hemlock and Canada yew from reproducing, leading to their disappearance in some areas. The loss of some plant types can lead to the local elimination of dependent insects, (e.g. insects that only pollinate lilies). Repeated browsing by deer can also alter the vegetation”s structure, which can reduce the variety of songbirds found in an area. For instance, a study in Pennsylvania revealed that when deer densities were high (65 per square mile) versus moderate (10 per square mile) they lost a quarter of the songbirds that nest in the middle tree branches, and numbers of birds that were still present declined by 37 percent. Eastern wood pewees, indigo buntings, least flycatchers, yellow-billed cuckoos and cerulean warblers were not found on plots with more than 21 deer per square mile. The eastern phoebe and American robin were no longer observed at deer densities of 65 deer per square mile. Even small mammal communities are affected – the diversity and abundance of small mammals was lower on the unhunted property where I studied whitetails in south-central Wisconsin.
You can maintain lower deer densities, and thus a more natural plant and animal community, by including some form of deer hunting in your land-management plan. If deer hunting is not part of your plan, you may see a loss in the numbers and types of wildflowers, shrubs or trees in your woodlot. These plant changes can lead to changes in the songbird, small mammal and/or insect communities on the property.