Nature Notes

Slowing Down

The trees are mostly bare. A willow is still hanging onto yellow-green leaves, providing a bright spot in the otherwise brown-and-gray landscape. A dogwood also retains some fall color.

By Holly Einess

The weekend forecast calls for below-freezing highs, so I decide to make a weekday visit to the Arboretum and take advantage of what’s likely to be the last warm day for a long while. My car thermometer registers 64 degrees when I arrive.

As I start my walk around Green Heron Pond I see and/or hear goldfinches, woodpeckers, blue jays, chickadees, robins, cedar waxwings, cardinals, nuthatches, Canada geese, and crows. Like me, they seem to be reveling in the mild temps. Also like me, these birds will be spending the winter here in Minnesota. The fruits of two native plants found near Green Heron Pond—highbush cranberry and winterberry—will be important winter food sources for some of these avian residents.

Highbush cranberry and winterberry

A dead tree is host to a variety of lichens, ranging from white to blue to various shades of green, creating a lovely palette. There are about 750 species of lichens in Minnesota, and 15,000 to 20,000 worldwide. A lichen is a composite organism, composed of an alga and a fungus living together in a mutualistic relationship—the alga provides food through photosynthesis and the fungus provides moisture and protection from the environment. For more on lichens, check out this article from Minnesota Conservation Volunteer magazine.

Lichens

The trees are mostly bare. A willow is still hanging onto yellow-green leaves, providing a bright spot in the otherwise brown-and-gray landscape. A dogwood also retains some fall color.

Last of the fall color

The breeze grows stronger and I can feel the temperature dropping. I’m therefore surprised when I see a painted turtle in the pond below the Snyder Building. It is in a sunning-itself posture, despite the dark gray skies and chilly air. Soon this turtle will make its way to the bottom of the pond and enter a state of brumation, akin to hibernation in warm-blooded animals. Its heart rate will reduce to around 10 beats per minute, and its metabolism will slow enough that it can survive without food until spring. It will also take in oxygen differently. During warm weather turtles breathe oxygen into their lungs, just like mammals do. But during brumation, their bodies draw oxygen from water as it passes over blood vessels in the skin, mouth, and cloaca (yup, butt-breathing). Toward the end of winter, as they’re coming out of brumation, turtles may be seen swimming under the ice.

Painted turtle

A pair of mallards is swimming on the Iris Garden pond. Most likely these two will migrate soon to the southern U.S. However, a small percentage of Minnesota mallards remain in our state all winter, so long as they have access to open water and a food supply.

Mallard pair

As the days shorten and temperatures drop, much in nature slows down and goes dormant. I find myself, too, aligning with the rhythms of the season, appreciating the opportunity to draw in and be still.

Holly Einess is a Minnesota Master Naturalist Volunteer.

1 comment on “Slowing Down

  1. Thanks Holly. You could feel it coming.

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