A UGA colleague stopped by my office to see if he could come out and gather some mistletoe.

Our house is partly surrounded by trees. Out beyond the borders of the tended area are woods, bushy areas and fields. We have lots of mistletoe in the water oaks near the house, so I said, "Come on."

This got me to speculating as to why mistletoe is so often close to houses and other buildings.

Where do you see the most mistletoe? In the middle of the woods? Or in front yards, backyards and the courthouse square? Our yard has lots of mistletoe, but our woods have little or none.

American mistletoe is a parasitic plant that lives on branches. It will live on 100 kinds of trees in the Southeast. But water oak, Quercus niger, is perhaps its favorite Georgia host.

When we built our house 18 years ago, mistletoe was scarce in our yard. Since then it has taken over to the point that our water oaks are suffering.

I've noticed that certain birds -- one species in particular - - move the mistletoe from tree to tree and branch to branch.

Birds eat mistletoe berries. Then, after digesting most of the soft parts, they pass their lacquer-like droppings, which stick the seeds to the branches.

Thus held to the branch, the seeds germinate, and the new plant penetrates the bark. The branch grows around the new plant, and the newly established mistletoe sends out new leaves and twigs.

Mistletoe plants often become so numerous that they may deform and eventually kill the tree.

Georgia has well over 300 kinds of birds, but only a few berry-eating species are here in the winter to eat mistletoe berries. One of those, a highly valued bird of Southern song and story, is the No. 1 spreader of backyard mistletoe.

The culprit is the mockingbird.

Mockingbirds are fruit-eating birds. But their habits are unlike those of robins and cedar waxwings, which roam in flocks throughout the countryside, eating berries whenever they find them.

Flocks of cedar waxwings and robins often don't linger long. They're here today, gone tomorrow. They don't have the mockingbird's love of backyards and courthouse squares.

The mockingbird is with us day after day, week after week, all winter long, to leave his sticky, seed-laden droppings on the branches of our trees. It's as if he's planning his own future food supply.

Mockingbirds sometimes appear in wild places, especially near concentrations of fruit. But they're most common near people. They seem to find just the right habitat in our backyards.

I haven't seen any research to support this idea. But I'll bet if ornithologists study the relationships between peoples' yards, mockingbirds and mistletoe, they'll find mockingbirds are the primary deliverers of mistletoe.

For mockingbird lovers, I guess this is a reason to like mistletoe. More mistletoe means better winter habitat for mockers. Mistletoe is also the larval food plant of the great blue hairstreak, one of the Southeast's most beautiful butterflies.

If you have trees heavily infested with mistletoe, maybe this winter you can plant some mistletoe-resistant trees. Then when your current trees die, your new trees will be well on their way.