The Study of Phenology

“Many of the events of the annual cycle recur year after year in a regular order. A year-to-year record of this order is a record of the rates at which solar energy flows to and through living things.  They are the arteries of the land.  By tracing their response to the sun, phenology may eventually shed some light on that ultimate enigma, the land’s inner workings.” –Aldo Leopold, A Phenological Record for Sauk and Dane Counties, Wisconsin, 1935-1945

 

Phenology is a segment of ecology focusing on the study of periodic plant and animal life-cycle events that are influenced by climate and seasonal change in the environment. Skunks emerging from winter dens, sandhill cranes trumpeting their return, and seeds ripening are all examples of annual phenological events. Phenology is derived from the Greek word phaino meaning to show or appear, indicating its principal concern with the dates of first occurrence of natural events in their annual cycle.

Phenological first began being recorded at the Leopold shack and farm by Aldo Leopold in 1936. Leopold took recordings from 1936-1947 in and around this landscape, which inspired Leopold's seminal work on conservation: A Sand County Almanac.

Nina Leopold Bradley continues to carry on her father’s work today, compiling a robust phenological database spanning from 1974 through the present. She has found that a substantial number of phenological events occur much earlier now than they did during Leopold's lifetime. Several studies have shown a significant trend for an earlier occurrence of spring phenological events suggesting some species are changing behaviors in response to climate change. Some species are expanding or shifting their ranges. The tufted titmouse, a songbird with an unmistakable call, did not occur during 1936-1947, but has become a year-round resident at the Leopold farm in Nina Leopold Bradley’s time.

Keep track of phenology in your own home!

We have several tools you can use to help you keep track of phenology just like we do here at the Aldo Leopold Foundation. Please download and use the following to help you:

Introduction to the Phenology Project: An overview to get you started. Download PDF.

Day-by-Day Observation Tracker: Use this document to help you know what events you might expect to see on each day of the year and record your own observations. Download PDF.

Phenology Photo Gallery: Not sure you can identify some of the species on the list? Use this field guide to help you. Download PDF.

 

Phenology Calendars

Each year, the Aldo Leopold Foundation is involved in publishing the Wisconsin Wildlife Phenology Calendar. It incorporates Aldo Leopold and Nina Leopold Bradley's average dates for phenological events in Wisconsin, paired with stunning wildlife photography. This year, the calendar theme is the plants and animals of A Sand County Almanac. Each month, learn about a member of Wisconsin's ecological communities that was featured in Leopold's famous book. Calendars are sold out for this year, but check back in the fall for information on the 2013 calendar!

The Wisconsin Wildlife Phenology Calendar is a partnership between the Aldo Leopold Foundation, the Natural Resources Conservation Service, the US Fish and Wildlife Service Partners for Fish and Wildlife, and UW-Extension. It has been produced yearly since 2004.