Zugunruhe [to state the obvious] is a German word. It describes this restless pre-migratory behavior.
When the days get short (and they have) geese are instinctively programmed to migrate. Decreasing daylight seems to stimulate the brain and endocrine system and the birds respond by exercising their flight muscles, eating more, making lots of noise.
So if it seems to you that the geese are flying around in circles every day, it’s probably because they are. Zugunruhe. Flying is a strenuous exercise requiring very high rates of aerobic energy with prolonged periods of muscle stress and extreme oxygen consumption. Consequently, geese become ravenous (eating enough to build up body fat) and though they probably don’t know why they need to get in shape, geese fly several hours a day to build their muscles and endurance.
Some birds get restless and begin migrating in fall even before cold weather and lack of food force them southward. Perhaps some of the geese we see in October may have come from points north. Hard to tell. Canada geese from Canada honk pretty much like locals, eh?
Truth is, if the birds were running out of food, they’d be out of here faster than you can say “skein of geese.” For now, food is available. Canada geese eat insects and small water creatures, but mostly, they eat plants.
Geese can gobble plants on land or under water. They love corn and other agricultural plants. But in fall and winter, geese prefer the rootstalks of water plants. These bulbs are nutritious because water plants store food in their stems and roots for next year’s growth rather like potatoes and carrots. If geese can get to the roots of water plants, they can survive winter.
As long as we have open water, geese will hang around on the Door Peninsula. After all, geese have waterproof feathers and their feathers have goose down linings. The cold never bothered them anyway.
It’s all about survival, and according to a feature I heard this week on Interlochen Public Radio, geese that winter in urban areas have a much better chance at survival than the birds that fly south for the winter. Apparently, the availability of food is not the reason.
In the interview, Michael Ward, an associate professor in the Department of Natural Resources and Environmental Sciences at the University of Illinois at Urbana-Champaign, described his research on the overabundance of Canada geese in Chicago. He explained, “We learned that [geese] weren’t going there for food. They were going there because there were no hunters, so all of the Canada geese that spent the winter in Chicago survived, whereas half of the birds that decided to leave the Chicagoland area and go to areas where hunting is allowed and more prevalent.