Goshawks, Old-Growth, and the Tongass National Forest

The Tongass National Forest in southeast Alaska is the largest national forest in the U.S., and the heart of the largest coastal, temperate rain forest in the world.  It is a vast, lush labyrinth of scattered islands, deep fjords, rugged mountains, glacial-fed rivers, and large expanses of old-growth hemlock, spruce and cedar – some of which are more than 1,000 years old.  The forest is home to black bears, brown bears, wolves, wolverines, mountain goats, moose, martens, otters, and Sitka black-tailed deer.  Its streams support all five species of Pacific salmon found in North America.  Raptors haunt the canopies of its remaining stands of old-growth.  But of the forest’s many inhabitants, perhaps the most remarkable—and imperiled—is the goshawk.

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Goshawks have broad, short wings and a long tail, which enable them to accelerate quickly and maneuver deftly.  This makes them well-adapted to hunt the squirrels, grouse and songbirds that inhabit old-growth forests.  Huge, old trees benefit goshawks by providing sturdy branches on which to build nests, and thick canopies to protect them (particularly fledglings) from avian predators like red-tailed hawks.  Thus, it is no surprise that goshawks in southeast Alaska spend most of their time (page 37) in these ancient woods. 

A particular subspecies of goshawk, the Queen Charlotte goshawk, inhabits the Tongass.  Queen Charlotte goshawks are the smaller, stockier, coastal cousins of the more widely-distributed northern goshawk.  They live only in southeast Alaska and the western coast and islands of British Columbia.  Unfortunately, due to historic and continued old-growth logging (primarily by clearcutting), their habitat is disappearing, and their numbers are falling: the U.S. has already designated them as “threatened” in western British Columbia; and a federal judge, more than a decade ago, said there was “no doubt” that “the goshawk’s numbers are declining in southeast Alaska.”  The Fish and Wildlife Service estimates there are about 350 breeding pairs left in western British Columbia; there are probably less than 300 pairs in southeast Alaska.

Three years ago, the U.S. Department of Agriculture announced its goal of transitioning away from large-scale old-growth logging in the Tongass.  The practice still continues, but the forest is currently conducting a review of its land management plan.  NRDC submitted comments reminding the Forest Service of its commitment, and of the likely consequences for old-growth-associated species like goshawks if the transition isn’t completed soon. 

We explained that goshawks in southeast Alaska are particularly vulnerable for a number of reasons.  They live in an environment with low prey abundance that is naturally fragmented by ice fields, muskeg bogs, steep terrain, and scattered islands.  The population is genetically isolated due to high mountain ranges and vast expanses of ocean.  Past practices of “highgrading”—i.e., disproportionately cutting down the oldest, biggest trees in the forest—have, in turn, disproportionately destroyed the exact habitat goshawks most prefer. 

Further, goshawks are territorial.  Studies (page 46) indicate that, to provide sufficient foraging and nesting habitat, about half of a goshawk’s territory must be covered by old-growth forest.  Past and present logging, however, has eliminated and fragmented much of the old-growth remaining in southeast Alaska.  This has forced goshawks in the Alaska Panhandle to maintain larger territories (some covering hundreds of thousands of acres) than anywhere else in North America.  As a result, goshawk densities and nest productivity are low, and starvation—especially in the winter—is common.  As the Fish and Wildlife Service (page 66) has noted, it is unclear how much larger these territories can become before the caloric return simply cannot compensate for the energy expenditure required to canvass such enormous areas:

The energetic demands of foraging increase with distance traveled.  The thresholds for individual survival and for supplying food to nestlings and a brooding mate in this energy balance are unknown, but habitat alteration that decreases foraging efficiency will push individuals and broods toward that threshold.

The need to transition away from large-scale old-growth logging in the Tongass is urgent.  Old-growth logging harms not only goshawks, but salmon, bears, martens, and many other old-growth-associated species.  It also threatens the traditional ways of life of southeast Alaska Natives.  The time has come for the Forest Service to turn its vision into reality.  The fates of goshawks, and many other forest inhabitants, depend on it.

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