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Audubon Avian Research Launches Study on Insect Diversity and Abundance
By Sue Kennedy
Several times on the trail in the Fisherville Brook Wildlife Refuge in Exeter, RI, Charles Clarkson, Audubon Director of Avian Research, slows his pace a bit, tilting his head to target in on a crisp trill here, a lower warble there. “Wood Thrush,” or “Ovenbird,” he’d offer to a small corps of volunteers, maybe taking a couple steps off the path to take a longer listen to a particular call.
But this foray into Fisherville, a wildlife refuge with more than 1,000 wooded acres, isn’t directly focused on the birds that Clarkson hears and names. Rather, it’s on insects, and with good reason. “It’s actually pretty basic – bugs are bird food,” says Clarkson stopping on the trail once more, this time to grasp a thin branch on a sweet birch and examine the undersides of several small leaves, light green in the still cool, still damp, early May air. “And the fact is, if we’re really going to get a better handle on how to truly support and care for bird species and the ecosystems they depend on, then we need to know what birds are eating and where they’re able to find their food sources.”
He points to a tiny ball of fine, ragged grey strands attached to the underside of one of the leaves. “See? Probably the leftovers of an insect egg mass, so that would be something that we could note in the data collection for this.” Murmurs of recognition and understanding ripple back and forth, and the group sets forth once more, with a pair of volunteers comparing schedules for the survey work they’d soon be undertaking for the project.
Clarkson smiled broadly as he listened to the planning. “People love surveying birds, but bugs? These folks deserve a prize,” he said, laughing. His smile fades into a thoughtful frown. “But this kind of work is very important, and it represents the extent to which we are finding it necessary to fully understand a bird’s world, so that, ultimately, we can target solutions to save habitats so we can save species.”
No Bug-sized Issue
A bird’s food may be small – protein, often from insects, is a primary nutrient source for most avian species – but it plays a clear and critical role in species survival, not to mention habitat conservation and ecosystem balance, both important for wildlife and humans alike. Clarkson explains that documenting the kinds and amounts of insects at Audubon conservation areas can inform understanding of which birds are more likely to be able to meet their nutritional needs at the sites. Alternately, the same information can also say something about insect or resource deficiencies or lacks.
It’s part of the overall Audubon Avian Research Initiative, with this particular focus reflecting the emergence of science in 2019 documenting significant losses of bird species in major habitat areas, countrywide. Audubon recognized the need for local-based information, and when Clarkson came on board in 2021, he started planning the study that will take a close look at what local birds are able to find to eat.
“We’ve got to remember that not all birds are capable of eating any ole’ bug that comes its way,” says Clarkson, pointing out that spongy moth caterpillars aren’t eaten by many bird species in the United States in general, as the insects’ spiny hairs are harsh deterrents. “And actually, many birds are quite specific about which insects they will feed to their chicks, so it’s really important that we up our knowledge of what’s available to birds, and where their food sources are. What we need to hone in on is where there are robust matchups between bird species and food sources, as well as where there are mis matches, which can be very disruptive to the health of bird species and the ecosystem in general.” How disruptive? Birds mismatched from their food sources may try to raise young without adequate insect prey to do so, and as a result, their productivity suffers as fewer chicks survive. “If this happens multiple years in a row, it can contribute to population-level declines,” explained Clarkson. “This is what we are seeing in a number of bird species that are dealing with large mismatches with their prey.”
Creating the “Bird Food Baseline”
Clarkson jokingly deprecates about the work –“Bird Food Baseline,”– but the entirely serious undertaking has required significant preparation and planning. The project, he explains, is focused on several key Audubon conservation properties which host specific “Responsibility Bird” species at any point during their annual cycle, such as the Common Yellowthroat and Wood Thrush. The organization will monitor these species in hopes they can establish conservation plans to promote long-term ecosystem health for these birds throughout the Northeast. Within each property, Clarkson has marked out six study areas, with each area made up of a group of trees – one lead tree with four adjacent or surrounding trees. On each of the study trees, 50 selected leaves will be observed by Clarkson and his team on numerous visits during the June to September data collection frame this year. Besides the Fisherville property, 12 other Audubon wildlife refuges in Rhode Island will be part of the study, with nearly 400 trees providing the basis for observations of insect existence on the leaves. The information – including smartphone photos, counts, and descriptions of insects and eggs – will represent a solid initial gathering which will be fortified with additional repeat surveys for at least the following year, with a third year ideal and likely.
Clarkson says he purposely chose the tree rings on the properties with a couple goals in mind, mainly making sure that community scientists can easily and speedily access the trees and their leaves – that meant picking groupings close to main trails, with branches no longer than an arm’s length away. “We are so lucky to have a team, mostly volunteer, who are willing to go out and do this for the benefit of birds, science, and conservation goals,” he says, noting about 25 volunteers have been assigned to refuge study areas. “I needed to be sure I was making it as feasible for them as possible, and this, in turn, helps ensure that the data are as robust as possible.”
The project is dovetailing into a larger National Science Foundation “Pheno Mismatch” effort to document food sources for birds across North America, and Clarkson expects to make use of available science and outreach resources to bolster the local work as much as possible, with plans that include encouraging Audubon community members to follow the project on a phone app. “We’re starting to get to the issue of documenting the information we need regionally to understand where we are doing a good job of supporting bird and ecosystem needs, and, conversely, where we really need to do more work,” he says. “If we have the data in hand, we can better plan, collectively, how to ensure that critical bird species can find and make use of food sources necessary for their survival and, ultimately, the health of the overall environment and our human world.”
Besides informing national and regional policy-making for the enhancement of bird habitat, the information that Clarkson collects and analyzes will also provide valuable data to leverage and guide Audubon’s conservation work for its overall Rhode Island portfolio. “We’ve come to a time where it really is no longer enough to simply collect information about the birds themselves,” says Clarkson. “If we’re really going to get some traction concerning the long-term health of our conservation areas and the species they support, then we’ve got to start understanding how they’re using the landscape and the choices they’re making – including the foods they’re choosing to eat.”
We’ve come to a time where it really is no longer enough to simply collect information about the birds themselves… we’ve got to start understanding how they’re using the landscape and the choices they’re making –including the foods they’re choosing to eat. - Dr. Charles Clarkson
Community Scientists on the Lookout for Caterpillars
As Clarkson’s scientific study gets underway, he and the Audubon team will be supported by the corps of volunteers, community scientists who received information and a basic training once they signed up. The makeup of the volunteer group reflects a broad range of the Audubon audience; for example, at the Fisherville visit, Audubon Board Member Don Heitzmann, of Exeter, a retired software engineer who has taken part in many Audubon conservation efforts, took the tutorial tour with Abbey Chrupcala, of North Kingstown. A newcomer to Audubon community science initiatives, Chrupcala signed up for the insect survey as she enjoys regular treks at the conservation area.
While on the tour, Heitzmann, with pant hems deftly inserted into thick socks that provided tick bite protection, used the faceto-face time with Clarkson to wade through some details on marking leaves on study trees. Further along, after becoming familiar with the brightly tagged tree groupings that generally featured common species like sweet birch, ironwood, and red maple, Chrupcala and Heitzmann talk more about their reasons for taking part in the effort.
Each brings a different perspective to the research project. “I’ve done this for a long time, and I know how valuable it is,” says Heitzmann. “I love birds, I love the environment, and Audubon is the best way to go to help it all. I do this as often as I can.” For Chrupcala, who calls her regular walks along Fisherville’s wooded trails “an important part of my life,” she thought the project was an opportunity to weave her beloved activity into the larger good. “I haven’t really done something like this before, but I know this area well, and I love it here – so it’s sort of doing two good things at once.”
And by the end of the tour, both know what Clarkson hopes they’ll find often on their study visits. “Caterpillars,” says Clarkson, replying to the group’s question about local birds’ favorite foods. “Caterpillars, caterpillars, caterpillars – they’re basically protein bombs for birds, especially young birds that really need those extra nutrients to grow and get strong.” And with most birds being “insect generalists,” Clarkson expects that volunteers will be recording a wide-ranging buffet for the birds, including spiders, ants, grasshoppers, crickets, beetles, and cicadas.
And again, says Clarkson, following up, it’s still important to remember that not all caterpillars, not all insects, can answer the food needs of all birds. “Hate to bring them up once more, but not many species here in this wood will eat spongy moth caterpillars,” he said. Still, caterpillars, in general, he says, are fine foods for the bird species at the Audubon conservation areas, and lots of other insects make for tasty and healthful meals as well. That’s why it will be important, Clarkson says, for as many instances of insect life found on study leaves to be noted, even photographed, for the data bank he’ll be overseeing.
Data Gathering for Good Guidance
As the group winds its way back along the main Fisherville trail, Clarkson points out the widespread mist of green leaves spreading through the forest; he estimates that the volunteers will probably be able to start visiting their assigned sites within a couple weeks’ time. “Once leaf-out happens, and the insects start living, growing, and moving on the trees, then this can really get underway,” he says, as “It’s almost showtime, we’re almost there,” he says.
At the same time, he says, as the group makes their way to their cars in the Fisherville lot, the work is just beginning. Data gathering takes patience, Clarkson notes, but the reward will be worth it. A solid baseline of three years of data can eventually inform the policy and practice that must take place, if many birds, like the Wood Thrush heard earlier, are to be able to continue finding the food they need to survive in the area. “Doing this work now, while engaging the community, sets us up to be much better prepared,” Clarkson finishes, “to understand what we need to do to keep these species here and healthy, hopefully for the long run.”
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Sue Kennedy is a communications specialist for the URI Coastal Resources Center, serves on the Warwick Wildlife & Conservation Commission, and enjoys freelancing; reach her at skennedy1168@gmail.com.
