All naturalists keep their eyes and ears open when outside. A naturalist might note a lot of turkey vultures this spring. Or, wow, the tree swallows came back early this spring. Or, I hardly see rose-breasted grosbeaks anymore.

These observations have value, but each is a single data point and may not indicate a general trend. To really detect patterns in nature, we need many observations to get a clear picture. Baseline data allow us to gauge changes in population numbers, geographic range, migration, and reproductive success.

Acquiring such information is beyond the capacity of any researcher, no matter how energetic. Rather, researchers have harnessed the power of interested naturalists to gather data. The term “citizen science” was coined in 1989 to describe projects that rely on the collective contributions of amateur scientists.

A just completed example of citizen science is the Maine Bird Atlas, a five-year study to document the geographic distribution of breeding birds and wintering birds in Maine.

This project had contributions from over 3,000 volunteers who submitted more than 125,000 checklists. That’s the power of a crowd.

The Maine Atlas team is already working on finalizing maps, analyzing the data, and writing the species accounts, so look for a book in the next two or three years.

This project is the second atlas of Maine birds. From 1979 until 1983, volunteers produced the first breeding bird atlas for Maine. This project involved far fewer volunteers and had a much coarser geographic focus. But this project provided the baseline for use in the newer atlas to consider changes in breeding ranges of our birds.

I usually grin a bit when I hear the term citizen science. Yes, the phrase is only 34 years old, but projects relying on volunteer naturalists have a longer history. The grande dame of citizen-science projects in North America must be the National Audubon Society Christmas Bird Count (CBC). The CBC began in 1900 and is still going strong. Sampling the same circle with a 15-mile radius each December allows us to gauge changes in winter bird distribution and abundance.

In the 1950s and early 1960s, birders were noting that many of our breeding species seemed less abundant. Those observations coincided with the publication of Silent Spring by Rachel Carson, alerting us to the dangers of the insecticide DDT and other harmful products. Still, hard data were needed to establish that those individual observations indicated broader declines.

In 1966, the first Breeding Bird Surveys (BBS) were begun. Conceived by Chan Robbins, a U.S. Fish and Wildlife Service biologist, these surveys involved the sampling of 50 stations along a 25-mile route. Each stop is sampled for three minutes, with all birds heard and seen tallied. The BBS data showed that many neotropical migrants were indeed showing precipitous declines. This continuing project allows us to see the distribution and abundance of all breeding species across North America. The BBS is also a citizen-science project begun before citizen science was a phrase.

The Maine Department of Inland Fisheries and Wildlife, in collaboration with other Maine scientists, has conducted other citizen-science atlas projects. The first amphibian and reptile atlas was published in 1999, and a second atlas is now underway.

Atlases for some groups of insects have been completed. The Maine Dragonfly and Damselfly Survey was conducted between 1995 and 1999. The Maine Bumble Bee Survey took place from 1999 through 2006. The Maine Butterfly Survey relied on field work from 2005 through 2017. This atlas will be published in October by the Cornell University Press.

If you are interested in participating in a citizen-science project, consider joining the Firefly Atlas Project. Who doesn’t love fireflies? Records are gathered by capturing fireflies, photographing them, and noting their flashing pattern. The fireflies can then be released. Find more information at fireflyatlas.org. Maine only has 15 species of fireflies, so the project provides a great chance to learn most of Maine’s fireflies.

Herb Wilson taught ornithology and other biology courses at Colby College. He welcomes reader comments and questions at whwilson@colby.edu