By Kate Crowley
I am a Minnesotan who likes winter. I like the beautiful images of snow falling and creating landscape-scale snow globes. I like being able to ski our trails and absorb the silence of the forest. I like the sense of hibernation too, when our homes become sanctuaries of warmth and peace. I even enjoy the act of shoveling because it gives me a real sense of accomplishment. I admit that I do not have to face the daily trials of bad driving conditions and cold cars in the morning, which I believe are the cause of most people’s angst. So, living through December, January and February is not a hardship for me and it usually isn’t until later in March that I start to get spring fever.
So, it wasn’t wishful thinking on my part when I walked past a townhome on a corner in NE Minneapolis last Saturday and saw two American robins in the yard. I did a double take, but then stopped to watch as they pecked at the exposed grass under a pine tree. The temperature had risen into the high 30s and the snow was melting fast. However, try as they might, they weren’t going to pull any earthworms out of the frozen earth.
Finding robins in Minnesota in winter is not without precedent. These are not birds that have gotten their calendars mixed up and come north far too early. These are birds that never left.
Looking around the yard I noticed two fairly large crabapple trees, with lots of dried fruits still hanging from the branches. While robins are generally ‘meat’ eaters, they will change their diet when their preferred source of food disappears. This is when they become ‘frugivores’ (fruit eaters). Sumac, hackberry, and buckthorn (that invasive scourge of our forests and gardens) are some of the other species the robins will go to for sustenance.
You have probably heard tales of robins appearing to be drunk after eating mountain ash berries in late winter. As they begin to thaw, fermentation takes place with the natural sugars in the berries. A bird’s system can be overwhelmed by eating too many of these ethanol filled fruits. Cedar and Bohemian waxwings will do the same, but they actually have larger-than-normal livers to help them process the fermented berries. When the birds become intoxicated they will often fly into windows and other solid objects, leading to injury and death. They can’t know that too much of a good thing can bring serious trouble as they swallow the berries one after the other.
Besides fruits or berries, overwintering robins must have water. Eating snow is too energy intensive for their bodies and finding open water in a Minnesota winter can be a big challenge. The two birds I saw were in a neighborhood not far from the Mississippi River, which remains opens because of St. Anthony Falls, so they were in a good place for their winter sojourn.
I don’t know whether these robins were male or female, but oftentimes the male will overwinter in an area, giving them a head start over other males when spring does arrive and it’s time to set up a territory and find a mate. Females have greater nutritional needs in order to produce eggs and raise the young, so having an abundant food supply is especially critical to them.
Another adaptation that helps the robins (and all other birds) who spend the winter in Minnesota is the extra growth of downy feathers that occurs as the months grow colder. Anyone who has worn a down jacket or slept under a down comforter knows the wonderful insulating warmth those feathers provide. So too, do the birds find more protection and comfort when exposed to severe winter temperatures. If the feathers aren’t enough, the birds will shiver, thereby creating body heat for survival. But that technique is also energy intensive and birds must have a good supply of food to replace the calories that are consumed.
If you find any robins hopping around your home this winter, do not expect them to eat the bird seed you put out. They will however be grateful for any mealworms you might provide. Putting fruit out may not work at first because they are raised to expect fruit to be hanging from tree branches, not lying on the ground. One man who found a flock of robins in his yard came up with the ingenious idea of putting live mealworms into a heated bird bath. Unfortunately a single, dominant robin took over and wouldn’t let any of the other robins near his stash of worms.
Most of us will have to wait to see our first robins of the year, but you can be heartened by the fact that in only two months, the first arrivals of the season should appear.
***Correction for last column about the Ivory Gull. The gulls that are most common in Canal Park in winter are Herring Gulls, not Ring-billed, although they can be present also.