Bird-watchers like their lists, whether it’s the life list for birds seen over a lifetime or the Big Year list for birds seen in a calendar year. In Alaska, the Red List is the list of birds whose populations are struggling.

The most recent Red List includes 35 birds found in Alaska, including 14 that live in or migrate through the Interior. The birds include small songbirds such as the orange-crowned warbler and larger birds such as the snowy owl and a subspecies of Canada Goose.

Birds that make the list aren’t necessarily near extinction — orange-crowned warblers, for example, number nearly 80 million. The listed birds generally have populations moving in the wrong direction or populations that are still low from a previous decline. The premise of the list is that it’s difficult and costly to recover species that are at the brink of extinction, so it’s worthwhile to look for population declines early to protect the birds and their habitats.

The list published last year was the first that the statewide conservation group has made since 2010.

“We try to redo it every five years or so because Alaska is so important,” said Nils Warnock, the executive director of Audubon Alaska, the statewide office for the National Audubon Society. “We have birds that come from literally all over the globe to breed here.”

A few common themes likely link some of the declining bird populations, Warnock said. Climate change is one major trend. It’s drying boreal wetland like the swampy terrain around Fairbanks.

“We’re warming at twice the global rate. In the Interior we’re losing and we’re projected to lose a lot of permafrost. That’s affecting our boreal wetlands,” Warnock said.

This habitat loss hurts species that migrate through the Interior, including greater scaups — a midsized diving duck — and the lesser yellowlegs, a shorebird named for its stiltlike legs. These species use the boreal wetlands to feed and to breed. The yellowlegs are under pressure on both ends of their range because they’re popular with hunters in Suriname and islands of the Caribbean Sea, Warnock said.

Another group of related birds on the list are swallows and other insect-eaters. These birds include the olive-sided flycatcher, the Western wood-pewee and both the violet-green swallow and the bank swallow. These birds have large breeding ranges and aren’t as dependent on Alaskan habitats as some of the other birds on the list. But these insectivores have declined across their range.

The declines could be tied to both loss of boreal wetlands and global decreases to their prey, Warnock said.

“If you look worldwide, we’re losing insect populations, probably because we’re developing very effective pesticides,” he said.

The lists are based on the scores for bird species in four categories: the global population of the bird, the size of its range, the percent of the global population that lives in Alaska and the population trend. Among these four categories, the population trend is weighted in the score three times as highly as the other categories. If a species scores enough points and also has a declining or depressed population, it appears on Audubon Alaska’s Red List. A species goes on a secondary Yellow List if it has a high score but doesn’t have a declining or depressed population. Together, the two lists are known as the WatchList.

In addition to highlighting the many birds with struggling populations, Audubon Alaska highlighted one success story this year. The emperor goose of Western Alaska was previously on the Red List but was moved to the Yellow List because of population recovery. Because of the population increase, Alaska opened hunting for emperor geese last summer for the first time in 30 years.

The sizes of global populations matter because smaller populations are more vulnerable. Birds with smaller global populations get higher scores in the formula. Similarly, birds with smaller ranges get higher scores because they are more vulnerable than those with larger ranges.

Audubon considers the percent of a species population that lives in Alaska in the score as a way to measure stewardship responsibility. As the organization sees it, if a large percentage of a bird’s population lives or migrates through Alaska, Alaskans have a greater responsibility to protect the bird and its habitat.

There are many different ways to rank the health of a species. Among the most famous is the list the federal government maintains under the 1973 Endangered Species Act. Warnock argues the Audubon WatchList is useful because the formula is transparent and isn’t driven by politics.

“The Audubon list has no regulatory mechanism behind it. Anybody could do what we did: Put your science together, decide how you’re going to rank your species and come up with your list,” he said.

In addition to being a conservation tool, Audubon’s WatchList is a catalog of current bird research in Alaska that highlights the limited data researchers have on remote bird species. For example, the list reports the subspecies population of grey-headed chickadees found in northeast Alaska as “less than 5,000?” and states the bird “may be North America’s most poorly studied breeding bird species.”