Late last spring saw the passing of Nina Leopold Bradley, daughter of Aldo Leopold, at the age of 93. Like Aldo, Nina was a keen observer of the natural world and a devoted practitioner of phenology, the study of the timing of biological occurrences—such as bird migrations and plant flowerings. Aldo’s record of springtime events on his Saulk (AKA “Sand”) County, Wisconsin farm are from 1935 to 1947. Nina’s were at the same site from 1976 to 1998.

As described in the article she authored regarding her and her father’s observations, some events have remained relatively unchanged, for example, certain birds that are primarily keying in on day length for migration. But other temperature-related events such as flowerings and birds that migrate shorter distances have shown distinct patterns of increasingly earlier activity. What had for many centuries been an attempt to discover the predictable rhythms of nature has now become integral to the study of climate change.

Watch a video of Nina discussing her observations.

And here’s a video from Minnesota researchers on the question of how prairie, broad leaf forest, and the needle leaf forest may evolve. Especially at this speed of change, things can get very complicated.

“Keeping records enhances the pleasure of the search and the chance of finding order and meaning in these events.”
–Aldo Leopold

What had for many centuries been an attempt to discover the predictable rhythms of nature has now become integral to the study of climate change.