Wildfire smoke drifting into Massachusetts may do more than dim the sky and irritate people’s lungs. Scientists are working to determine how it affects birds—and local bird monitors are helping them gather the evidence. At Mass Audubon’s Drumlin Farm Wildlife Sanctuary in Lincoln, bird project coordinator Pam Sowizral and volunteers have checked nest boxes three times a week during spring and summer for nearly 20 years. They record nests, eggs and chicks that successfully leave the nest, continuing their work when smoke moves into the area as well as during other weather conditions. Those consistent observations can help researchers compare bird activity before, during and after smoky periods. The smoke may originate hundreds or even thousands of miles away, so its effects can reach communities far from the wildfire itself. Olivia Sanderfoot, a global change ecologist at Cornell University, is working with researchers across disciplines to build a field of study she calls “smoke ecology.” Smoke, she says, should be treated as a disturbance in its own right, separate from the fire that produces it. Scientists need air-quality measurements, satellite data and atmospheric models to understand where smoke travels and what it contains. Birds may be particularly vulnerable because their respiratory systems move air continuously through their lungs and air sacs. That system helps them take up more oxygen with each breath than humans do, but it may also increase their exposure to substances in smoky air, Sanderfoot said. Smoke can also disrupt the cues birds use to navigate their surroundings. Researchers have identified several responses: some birds stay put, others leave, and some reduce activities such as singing or venturing out. Those changes could limit exposure, or they could reflect birds feeling unwell, Sanderfoot said. Research by Sanderfoot and colleagues has also found that repeated smoke exposure appears to affect birds’ body condition, with exposed birds showing lower weight overall. The effects vary by species and individual, and scientists are still working to establish how well different responses protect birds. The work is challenging because smoke can arrive and clear quickly, and conditions vary with wind, rainfall and chemical changes in the atmosphere. Researchers also cannot ethically expose wild animals to smoke in controlled experiments. Instead, they are drawing on observations collected by birders, conservation groups and ornithologists across the country. Sowizral said the air felt different during smoky periods, but the conditions did not stop the sanctuary’s usual nest-box monitoring. That continuity may prove valuable as researchers try to understand how smoke affects nesting and breeding over time. Sanderfoot’s next goal is to identify possible “smoke refugia”—places where birds can find safer conditions while smoke is present. She wants to learn where birds go and what resources they seek, including whether access to water, shelter or food could help them. As wildfire seasons start earlier, last longer and burn more land, smoke is increasingly reaching places untouched by flames. For Massachusetts communities, the research could help conservationists and residents understand how to support wildlife during smoke events—and add to what scientists know about the broader health effects of worsening smoke exposure.