Aleutian seabirds are showing the effects of a changing marine ecosystem

The bodies of seabirds tell stories of the rapid change taking place in the North Pacific Ocean. Reading those stories requires some expert analysis.

That is where Douglas Causey, an ecology professor at the University of Alaska Anchorage, and his colleagues come in.

Causey, who heads a lab at UAA's Department of Biology, is leading a long-term project to examine seabirds — what they eat and how that reflects ocean conditions in a rapidly warming climate. His territory is the entire Arctic and subarctic, a vast region he has been studying his entire career.

"My students are convinced that started with Bering," he joked, referring to Vitus Bering, the 18th Century Danish explorer.

His work has taken him to Alaska's North Slope, Greenland and all the way to the North Pole. But in many ways, the southernmost region of his research, with its wide-open and choppy waters, is tougher territory, he said. "The hardest place to work is the Aleutians, by far," he said.

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For almost every year since 2010, he's been riding the U.S. Fish and Wildlife Service research vessel Tiglax as it sails along those isolated, treeless islands. The focus has been on the western Aleutians, though in 2015 the cruise went along the entire archipelago, more than 1,000 miles long.

Causey zeroes in on the birds, what they are eating and where they are finding their foods — a "very good indicator" of what is going on in the ecosystem, he said. Bird diets vary by species and span the marine food web, he said. "The food that they eat range from plankton all the way up to other birds," he said.

To find out, at least along the Aleutians, he has to shoot birds and make their carcasses available for dissection and chemical analysis.

It is an old-school method of research, the same used by naturalists in past centuries, Causey concedes.  But it is actually the least harmful method for sampling birds in the Aleutians, he said. The alternative would be to capture live birds at crowded breeding colonies, pluck their feathers and draw blood samples and possibly take biopsies of body tissue. Such activities — possible in some places of the Arctic and subarctic — would likely cause more damage to the Aleutian populations because their breeding colonies are huge, and human encroachments on them could trigger big disruptions and big reproductive losses.

The birds are killed in accordance with state and federal permits and academic standards. Collections totaled about 80 this year and about 170 in 2015, he said. The birds, of various species, are brought from the field to the UAA lab, where the analysis takes place.

Birds' stomach contents do not give many clues about diet, Causey said. To stay lightweight and aloft, seabirds digest their food very quickly, so there is only a short period of time to see anything useful there, he said.

Better information is found elsewhere in the bodies, like claws and muscle tissue. Feathers, in particular, provide good information because biologists know when different types of features grow in, or are shed, during molting, and can identify chemical fingerprints of different food types and put their consumption into sequential order.

They also have the advantage of preserved feather collections going back hundreds of years at research institutions.

Analysis of isotopes in the newly bagged birds and comparisons with collections amassed in the past shows some dramatic differences in diet and, by extension, the ecosystem.

"The patterns that used to exist for decades and decades are starting to break apart," he said.

A strong trend is to a more variable diet. "The variability is enormously increasing," he said.

That might not bode well for birds with more specialized food needs. Seabirds tend to feed relatively close to shore — and close to places on land where they make nests and breed their young. If preferred food is no longer available near those breeding sites, the birds might have to choose between reproduction and survival.

A possible victim is the red-faced cormorant, a species on decline in the Aleutians. In the Near Islands, the westernmost group in the Aleutians, there were 75,000 of the species decades ago. The situation was vastly different when he sailed there this year, he said. "Two months ago, if I saw 300 I'd be surprised," he said. "Before, they were everywhere. Now you would have to look very carefully to find even one."

The birds are ingesting more than food, the research has found.

As is the case elsewhere in the oceans, an increasing load of plastics is making its way into the ecosystem and into the bodies of marine animals, including birds.

Causey and his colleagues found that even in the westernmost Aleutians, far from any industry and even any other ships, small bits of plastic were widespread.

They launched their study into the problem in 2013 after birds near remote Attu Island were found with large chunks of plastic debris in their stomachs.

Two years later, about 25 percent of the birds collected had plastic beads in their stomachs. To birds, the pellets — called nurdles — might resemble tasty bits of plankton, Causey said.

The discovery of so much plastic has triggered a parallel research project led by Veronica Padula, a graduate student working in Causey's program. The same birds that are analyzed for signs of climate change are also being analyzed for effects of plastic consumption.

Aleutian birds are not facing the acute situation farther south, where birds like albatrosses are dying after eating big chunks of plastic from the Pacific Ocean garbage patch and other trash.

Instead, a more chronic but nonetheless alarming situation appears to be developing, Causey said.

The plastic nurdles soak up environmental contaminants like PCBs, and phthalates, chemicals used to make plastics more flexible, which are of particular concern. Phthalates are known to mimic hormones and act as endocrine disruptors, Causey said. Research so far shows that their effects on birds are magnified in embryos inside eggs, a troubling sign, he said.

The project Padula is leading is the first studying contaminants in Aleutian-area birds and, as far as UAA officials can tell, the first globally to quantify phthalates in seabirds.

The UAA team has been able to test about a fifth of the collected bird specimens and so far every one has tested positive for the phthalates, Causey said.

A newly developed test that analyzes swabs taken from feathers can be used on live birds, he said.

Other studies use the collected birds to examine parasites and avian viruses, Causey said.

Funding for the studies comes from a variety of sources, including the National Science Foundation and the U.S. Fish and Wildlife Service.