The science of nature: For citizens, by citizens
Amateurs serve as an early warning system for the state of the natural world
In their thousands, they are coming — into the forests, fields, and streams. They are fanning out across the globe, armed with new technology, and making unprecedented observations of nature. With their sheer numbers, they have the potential to transform the science of conservation.
They are citizen scientists. They are amateurs in the best sense of the word, with long-standing traditions. Many outdoor clubs, like the Peterborough Field Naturalists, have existed for generations; their ranks are filled with dedicated volunteers and devoted conservationists. But technology has empowered the modern naturalist with new ways of gathering and sharing observations of birds, butterflies, amphibians, and other wildlife.
The potential for science is staggering. Take eBird, a popular tool for birdwatchers. With an iOS or Android device, a birder can now record sightings on the go. Since its launch in 2002, eBird has amassed more than a half-billion observations of birds worldwide. Another 100 million observations are being added each year. This bounty of sightings, with its global reach, could lead to new discoveries, otherwise impossible or impractical. It could support conservation.
But one question remains: Can science rely on anecdotal observations from nonprofessionals? The answer is crucial. And recently, with the help of the Peterborough Field Naturalists (PFN), we sought an answer: At our disposal were observations of local birds, recorded in the PFN newsletter, The Orchid, since 1948. These anecdotes, spanning seven decades, represented a treasure trove. We wondered: Would naturalists’ observations reflect changes in the local bird community? Indeed, in the past 70 years, the Peterborough bird community has changed.
Some species have expanded their ranges northward: Northern Cardinal, House Finch, Purple Finch, and Red-bellied Woodpecker. Some species have become winter residents: Canada Goose and American Robin. And one species has been reintroduced: Wild Turkey. These trends are known. They are reflected in standard, annual surveys, such as Christmas Bird Counts (CBC) and Breeding Bird Surveys (BBS). In our analysis, we focused on these seven species. And we compared the two kinds of data, one unstructured (PFN), the other structured (CBC and BBS).
We looked at two indicators: The first record of each species (when was it first detected)? And its abundance (how many birds were sighted each year)? We anticipated some differences between the two kinds of data. After all, amateurs do not adhere to a strict protocol; they are more likely to report a species when novel. So we expected the naturalists to be first to detect any new arrivals. And we expected the naturalists to overreport a species when new to the area, and to under-report the species once it became mundane.
First, the good news. In nearly every instance, the Field Naturalists were first to notice the newcomers, well in advance of the formal surveys. In nearly every case, the PFN reported the new species before the CBC or BBS — on average by 1½ decades. That’s a big advance in detection.
Now, the not-so-good news. When it came to bird abundance, there was little correspondence between naturalists’ observations and formal surveys. Indeed, sometimes they indicated opposing trends: When naturalists reported many birds, surveys indicated few birds — and vice versa. Take the Northern Cardinal. Shortly after 1957, when this showy bird was first detected in our region, naturalists’ reports were frequent. By 1968, when the bird became commonplace, reports declined. Cardinals were more abundant, but less noteworthy. This has implications for conservation. Exotic species, like European Starlings and Zebra Mussels, are major drivers of biodiversity loss.
Documenting the early arrival and spread of exotics is a strength of citizen science. Amateurs are early warning systems. But we cannot rely solely on volunteer sightings to reflect changes in abundance. The decline of a species, for instance, may go unnoticed from anecdotes alone. Naturalists have served science for decades. The explosion of technologies, coupled with growing interest in nature, opens the door for even more powerful science. In the end, the biggest beneficiary of citizen science could be nature itself.