Monday morning was still and gray and cold in a way that makes nature in winter an authentic sensory experience. And so it was in the mixed woodland on the Meadlowlark and Sumac trails in Elm Creek Park Reserve in the northwest metro.

Amid aspen and oak, I set off with John Moriarty, senior manager of wildlife in the vast Three Rivers Park District. More than a walk like that of the snowshoers who tracked by, our outing over a few hours became a rich dive into a diverse ecosystem full of life and death and adaptation in Minnesota's harshest season.

It's terrain Moriarty knows well — on many levels. At 5,500 acres, Elm Creek is the largest of Three Rivers parks, and we inhabited but a slice of it along Rush Creek. He also just co-authored a new edition of the landmark book "Minnesota's Natural Heritage" by the late conservationist and educator John Tester. A road map through Minnesota's natural history, the book came out in late January.

We inspected the distinctive "monkey face" pattern of a leaf scar on a black walnut branch (leaf scars can help identify plants when they're dormant). Frosted wild plums and a few remaining catkins on a small hazel tree were a ready meal for something. Further on, we came upon remnants of nests, with fluffy down tucked into the birds' handiwork. Perhaps from the hybrid cattails nearby?

What we observed reminded me of author Tristan Gooley and his popular books on how to read nature and connect the dots, how that understanding can foster a new appreciation and empathy outdoors.

"Nature is not randomly scattered," Gooley wrote. "Everything has an association with time and place and other parts of nature."

"I see the connections," said Moriarty afterward, "such as the need for the dead trees for the woodpeckers, the fruit production of the plum, hazel, and viburnums."

Alas, as a conservation land manager, Moriarty is mindful of the broken side, too. We passed invasive species like bittersweet and buckthorn and saw an example of how a fungal disease of uncertain origin is killing Minnesota's butternut trees, a native hardwood and related to black walnuts.

Some other jottings:

-Pileated woodpeckers, the largest in Minnesota, and other birds wreaked havoc on a dead aspen, no doubt drilling for insect larvae in the soft wood.

-White-breasted nuthatches and chickadees flashed above. Were their nests close? Their secondary cavity nesters and are species typically seen together.

-Winter food sources stood out: From catkins on hazels to berries on sumac to viburnums like nannyberry.

-Everpresent at the trail's edge: dense areas of scouring rush, with bamboo-like, banded stems. The silica content in the stems made them a choice for cleaning long ago.

-A nest, maybe a catbird's, was wedged in the safety of a prickly ash plant.

-There were red cedars on the edge of meadow, one of three conifers native to the metro along with white pine and tamarack. The dense cedars are popular with roosting owls.

Every wild sign from a Monday walk in the woods held a lesson.