Puffins Change Parenting Roles During Heatwaves
Webcam study reveals how Atlantic Puffins in Maine change behaviour during marine heatwaves to help chicks survive
Shifting seas and struggling seabirds
Atlantic Puffins breeding on the islands of Maine are being forced to adapt as the Gulf of Maine becomes one of the fastest-warming marine regions on the planet. A new study by Julie Wallace and colleagues, published in Marine Ornithology, used a webcam installed inside a puffin burrow on Seal Island National Wildlife Refuge to reveal in intimate detail how rising sea temperatures and prolonged marine heatwaves are reshaping the birds’ parental behaviour and chick development.
Between 2017 and 2022, the researchers observed a single puffin pair through multiple breeding seasons, correlating burrow activity and chick feeding rates with satellite data on sea surface temperature. The results captured an unprecedented level of behavioural flexibility, showing that even in a changing ocean, puffins can sometimes adapt—but not without cost.
Hotter waters, hungrier chicks
Marine heatwaves (MHWs)—periods of unusually high sea temperatures—are increasing in frequency and intensity in the Gulf of Maine. These episodes disrupt the marine food web, forcing fish to shift distribution or become scarce. For puffins, which must find and deliver fish to their chicks daily, warm-water events can spell disaster.
In “normal” years, the female puffin was the main food provider, responsible for roughly two-thirds of all chick feedings, while the male focused on burrow guarding and chick protection. But during 2018, when an extended heatwave struck, prey became scarce and the usual pattern broke down. The male abandoned his guarding duties to help feed the chick, doubling his provisioning rate while the female’s feeding efforts held steady. Even so, the chick’s growth slowed dramatically, and it fledged 69 days after hatching—almost a month longer than usual.
Behavioural plasticity under pressure
This role reversal is the first documented case of male puffins shifting from nest defence to provisioning in response to food scarcity. It demonstrates a remarkable flexibility in parental behaviour, but also highlights the stress such conditions impose. The female’s reduced burrow attendance during hotter periods suggested longer, more demanding foraging trips, consistent with findings from other seabird studies under similar conditions.
The consequences of warming seas were not limited to adults. The chick from the 2022 breeding season faced repeated heatwaves and a diet dominated by American Butterfish Peprilus triacanthus—a deep-bodied, high-lipid fish that young puffins usually reject because it is too wide to swallow. Astonishingly, the chick devised a solution: tearing the fish apart and eating it piece by piece until it could manage the remaining portion whole. This improvised “piecemeal feeding” strategy, never before recorded, allowed it to fledge successfully despite challenging conditions.
Signals from a changing ocean
Across the study years, higher sea surface temperatures consistently correlated with lower feeding rates and reduced time spent in the burrow. Chicks grew more slowly and took longer to fledge when heatwaves were strongest. These fine-scale behavioural shifts mirror wider patterns seen across the Gulf of Maine’s seabird colonies, where productivity has fallen during recent warm years.
Wallace and her co-authors argue that the puffins’ flexibility—adults swapping duties, chicks learning new feeding behaviours—offers a glimpse of resilience. Yet they caution that this adaptability may have limits as marine heatwaves intensify and prey species continue to shift northwards. Even the most resourceful birds can only adjust so far when the foundations of their food web are eroding.
Watching the future unfold
The use of webcams has opened a unique window into puffin life, revealing behavioural details that would be impossible to capture by conventional fieldwork alone. For the scientists and volunteers monitoring the Seal Island colony, each season provides both hope and warning: the sight of a determined chick improvising with an oversized fish is both a triumph of adaptation and a sign of mounting environmental stress. As the Gulf of Maine continues to warm, these intimate glimpses may help researchers anticipate how seabirds—and the ecosystems that sustain them—will cope with an increasingly volatile climate.
October 2025
Read the full paper here
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