Data and code from: Sea ice perturbation and mass starvation of Thick-billed Murres

During spring 2022, thousands of Thick-billed Murres (Uria lomvia) died on
the southern Labrador and northeastern Newfoundland coasts. Location and
timing of the event were compiled from public sources, including social
media and institutions. Some retained carcasses were dissected and
compared to healthy birds. The rapid-onset, five-week event lasted from
March 18 to April 25, 2022, emanating from an impact site in southern
Labrador. Extreme winds compacted and reduced sea ice area, which exposed
sub-zero water temperatures and limited feeding options. Dissections were
performed to determine body condition and demographics of birds affected.
Neither sex nor age was associated with mortality, and a subset of
carcasses tested negative for influenza A. Carcass masses averaged 65.5 %
of the body mass of healthy birds, indicative of a threshold for stage III
starvation (protein catabolism). Photographs and measurements showed
significant pectoral muscle wasting, and pectoral mass was less than that
of healthy birds. The probable cause of the die-off is starvation
accelerated by a rapid drop in water temperature and limited foraging
options driven by a sea-ice perturbation. Ocean-climatic variability and
extreme events are expected to increase, posing challenges for polar
seabirds.