A mass dying of tufted puffins (Fratercula cirrhata) in the Bering Sea is at least partially the result of climate change, a new study reports.

Image credits Gregory “Slobirdr” Smith / Flickr.

A collaborative research effort between members of the Aleut Community of St Paul Island Ecosystem Conservation Office and citizen scientists at the University of Washington’s COASST program reports that the birds seem to have died from starvation. Tufted puffins feed on fish and smaller marine invertebrates, which in turn feed on plankton — stocks of which are declining due to warming climate conditions.

Puff! You’re dead

“This paper is a successful application of citizen science in the real world. Island residents collected high-quality data in real time and provided COASST with a detailed context for their analysis,” explains Lauren Divine, one of the paper’s co-authors.

“Without the positive and mutually beneficial relationship built over years of collaboration, this massive die-off of Tufted Puffins would have gone unreported in the scientific community.”

Tufted puffin colonies in the Bering Sea have experienced a massive die-off that the team attributes, at least in part, to man-made climate change. The team documented a four-month-long dying off of tufted puffins in the region. They further report that the Crested auklet (Aethia cristatella), another species which nests on the St. Paul Island more to the south of the Bering Sea, is also experiencing a similar decline.

Since October of 2016, local community (including tribal communities) members have recovered over 350 ‘severely emaciated’ carcasses of puffins and auklets, a press release of the paper explains. Most of these birds were adults in the process of molting, which the researchers note is a known nutritional stressor of their life cycle.

The timing also hints to the cause of their demise: a reduction in food resources in the area just before the birds entered molt. The team used wind data in the region to model beachings and calculated that between 3,150 and 8,500 birds could have died in the event. Roughly 87% of these deaths represented puffins, they add, in an area where previously, puffins made up less than 1% of the carcasses recovered in the region. Based on the sheer number of recovered carcasses, the team adds, it’s highly likely that the event affected the species throughout its colonies in the Bering Sea.

They suggest that climate-driven shifts in the availability and/or distribution of prey hit the colony at the onset of molt, causing the die-off. Rising sea temperatures are causing substantial shifts in ocean ecosystems the world over, the team explains, shifts that have previously been linked to mass mortality events in marine bird species. The Bering Sea didn’t escape such changes, with increased atmospheric temperatures and declining winter sea ice cover recorded since 2014. Such changes led to declines in key, energy-rich species in the region, and caused others to shift more northward — all of which left puffin colonies in the southern stretches of the sea hard-pressed to find food.

Further climate variability in this region is probable, according to the team, which suggests that this problem will only get worse — for puffins and other species of marine birds. We simply don’t know if these species will be able to adapt to their rapidly-changing environment in time, so we should do our best to monitor their situation, the team concludes.

The paper “Unusual mortality of Tufted puffins (Fratercula cirrhata) in the eastern Bering Sea” has been published in the journal PLOS ONE.