Large Vessels Pose Threat to Migratory Bird Species, Study Finds

DGHEYEY KAQ’/ANCHORAGE, Alaska (August 20, 2025)—A new study has revealed that some of North America’s most important migratory seabird thoroughfares are at risk from marine vessel traffic. Seabird biologist Kathy Kuletz, Michigan State University postdoc Kelly Kapsar, and Audubon Alaska’s Director of Geospatial Science Benjamin Sullender mapped the movement of large vessels and the seasonal distributions of certain seabirds. They found that heavy ship traffic frequently coincides with peak migration periods, creating potential for disturbance when birds are most vulnerable. “A multiscale seasonal examination of the risk of harm to seabirds from vessels based on co-occurrence in Alaskan waters” is published in Conservation Biology.

Several factors are drawing ships further north, including declines in sea ice, increasing Arctic resource extraction, and shifting fisheries. Ships can collide with wildlife, discharge harmful pollutants, accidentally catch birds or marine mammals while targeting fish, and spill oil, but new hazards are also emerging. Boats can now operate in the early autumn, and their lights can distract and attract migrating birds unaccustomed to anthropogenic light sources during fall migration—often with fatal consequences.

The analysis combined eight years of satellite-based vessel tracking with 16 years of at-sea seabird surveys to create seasonal “risk maps” of where and when seabirds and vessels overlap. The Bering Strait was a heavy vessel-bird conflict location, as was Unimak Pass in the Aleutians, where vessels travel at the same time as foraging fulmars and shearwaters.

“This study covers an enormous amount of area from the Aleutians all the way into the Arctic,” Kapsar says. “Having an idea of where and when seabirds and vessels are most likely to overlap can help managers and policymakers to implement more targeted interventions to minimize harm.”

The study urges better reporting of vessel-bird incidents and the use of targeted navigational measures—such as routing changes, speed limits, and reduced light pollution.

“We don’t want mariners to completely upend all their practices,” Sullender says, “but by carefully targeting actions like minimizing light pollution at the times and places that matter most to birds, we can make sure that our conservation efforts are effective in helping seabirds navigate our changing Arctic.”

Imagery is attached (please see credits in file name), and more is available upon request. For more information or to set up an interview, please contact Lauren Cusimano, Audubon Alaska’s Communication Manager, at 907-433-5300 or lauren.cusimano@audubon.org.

###

About Audubon Alaska
Since 1977, Audubon Alaska has been conserving the spectacular natural ecosystems of Alaska for people, birds, and other wildlife. Audubon Alaska uses science to identify conservation priorities and support conservation actions and policies, with an emphasis on public lands and waters. Audubon Alaska is a state office of the National Audubon Society. Learn more at ak.audubon.org.