When the phone rings at work, sometimes I know the answer; sometimes not. Recently, I had a call regarding robins staying during the winter (and what can be done help them). I knew just what to say.

Not all robins migrate. It really is that simple - they are short-distance migrants. They lack the ambition to fly very far each fall. Over the past 10 years, robins have been spotted during the winter months in every state in the U.S., except Hawaii.Her immediate response to my answer was, "But … robins mean spring is coming!"Well, no, not always.Why is it that we equate robins with spring? Maybe during a long winter, we are inside much of the time, or too bundled against the cold to notice them. But if we were to wander the garden or roam the woods we just might catch sight of a robin, even on a midwinter day.And, truthfully? Robins tend to roost in shrubs and bushes that supply tasty treats and shelter. They are not as obvious to us as they are in the spring when they are hopping all over the yard in search of worms.The American robin is a hardy and adaptable bird, comfortable in just about any habitat North America can provide.Robins have survived blinding blizzards, ice storms and nights as cold as 30 below zero. One way they keep warm is by eating high-energy foods, especially foods with a high fat content, which works as an insulator and an energy reserve.Robins can put on up to 15 to 20 percent of their body weight in preparation for winter by building up fat reserves.This stored fat becomes a fuel used to keep them warm. This process is called thermogenesis. This simply means shivering.Shivering creates heat and this shivering keeps their internal temperature somewhere around 104 to 106 degrees. Unlike the surrounding temperature, robins are toasty warm on the inside.So while you're freezing under all those layers, the robins are doing fine, appearing brave and prepared for anything.Feathers for protection, staying huddled in groups, seeking out underbrush that offer shelter from the harshest of conditions and increasing their food intake equals survival.Those feathers will shield them from the outside air temperature while causing warmed air to be trapped next to their bodies, which could mean a difference of more than 100 degrees.Occasionally, they will tuck in a leg or two under their feathers to protect them from the bitter cold. Just like when we tuck our hands into our pockets to warm them.The caller's concern was that with the ground being frozen, the robins would starve. Did you know worms make up about 15 percent of a robin's diet, along with some insects and invertebrates?Robins are primarily fruit and berry-eaters. Some of the foods they enjoy are bittersweet, bayberry, crabapple, hawthorn, high-bush cranberry and chokecherry as well as juniper, honeysuckle and sumac berries.In winter, with no earthworms to be had, a robin's diet changes to almost exclusively fruits and berries. The best winter berries are those that start out tasting too bitter to eat, and after freezing and thawing several times become tastier. Growing a winter fruit garden is a wonderful way to make life easier for wintering robins.And, of course, other birds will appreciate your efforts too.There you have it. If you live in Pennsylvania and see a robin in your yard in January or February, don't put your long johns away just yet.Think spring!Jeannie Carl is a naturalist with the Carbon County Environmental Center, located at 151 East White Bear Drive, Summit Hill. Visit

http://www.carboneec.org/ for more information about programs at the center.