Door To Nature: Phenology and May Day Discoveries

Roy and I kept daily records of the weather and what wildlife we saw around our home or during hikes. These records go back over 30 years. It is a process we call phenology (fi-NOL-o-gee.) 

Much of this information can be helpful in studying the last few decades of climate change. This winter was quite mild, with only a couple of bad snow storms. Now May is here, and I saw magnolias and flowering crab trees already in blossom before the month began. In years past, they weren’t in bloom until the middle of May. 

My woods contain thousands of giant trilliums, which are usually in full bloom in the second week of May. They started blooming this year by the end of April.

I found my first brown morel mushroom this year on May 1. That was the same day the first rose-breasted grosbeaks arrived at my feeder and I put out the hummingbird feeder. While doing yard work, I saw the first red-bellied and garter snakes of the season.

I received 1.2 inches of rain during the last five days of April, which is why I searched for morels. Often, I wouldn’t find brown morels until the last half of May. I have received just over an inch of rain this month, as I write this on the morning of May 5. That will make me look for more of these tasty mushrooms tomorrow.

Many years ago, Roy and I were members of the Wisconsin Phenological Society, and we would send in reports of what we were observing here in northern Door County. I looked up the organization and wrote to the president of the group to see if they are still active. I learned they are, but there’s no need to be a member. 

The Wisconsin Phenological Society formed in 1959 and had their initial formal meeting in 1963. It was the first such organization in the United States, and it became affiliated with the Wisconsin Academy of Sciences, Arts and Letters. Their website says they are a part of the USA National Phenology Network.

You can send in your observations to this network via its Nature’s Notebook project. Visit for more information.. 

Recording natural events and the dates they took place over many years is a form of citizen science. Citizen scientists work all over the country, including here in Door County through the Ridges Sanctuary, the Door County Land Trust, Crossroads at Big Creek and the Friends of Toft Point, which helps the Cofrin Center for Biodiversity at UW-Green Bay manage the Toft Point State Natural Area.

Citizen scientists monitor streams and beaches for water quality, track bat populations in local shelters, record the blossoming dates of native and invasive plant species, note wild bird observations on eBird app for the Cornell Laboratory of Ornithology, and list birds they see and hear during bird counts.

When you look up citizen science on the internet, you can find many organizations that benefit from these volunteer efforts, including Earthwatch Institute, the National Geographic Society, Adventure Scientists, NASA and the National Audubon Society.

I pulled up Roy’s daily notes from 20 years ago and see that many bird species are arriving about a week earlier now. The serviceberry trees, also known as juneberry trees, were blooming this year by April 30. In 2004, the first one was flowering on May 12. The deciduous trees were coming into leaf at the same time, but this year, they are leafing out in the first few days of May.

All these records made over the past decades will help scientists who study wildlife and global climate change. The weather records for one small area like Door County are not as important as the large-scale trends for an entire community of wildlife, but they can add to the statistics of how this earth is warming year after year.