Palm warbler. Photo by Jeff Nadler
Climate change, other threats put boreal species at risk
By PHIL BROWN
A few years back, Brian McAllister received a phone call from a man who wanted to see a boreal chickadee. That’s not so unusual, except he was calling from California.
“He flew into Montreal and then Saranac Lake,” recalls McAllister, who was then a birding guide. “I met him at his buddy’s house near Paul Smiths, and we went out to Bloomingdale Bog. Lo and behold, there was a boreal chickadee, and he was all excited. Afterward I took him to his friend’s house, we said goodbye, and he was gone within 24 hours.”
If you think that guy is a little nuts, you’re probably not a birder.
Although not all birders can afford to fly across the country for a day trip, many share the man’s passion. They’ll drive for hours to find species they haven’t seen before. Many plan their vacations around birding.
The birders who come to the Adirondack Park are not looking for blue jays, robins or other birds they can see at home. Most are seeking boreal species—birds that breed in Canada and in parts of the northern United States. Besides the boreal chickadee, some of the more coveted birds are the gray jay, spruce grouse, rusty blackbird, Bicknell’s thrush, and black-backed and American three-toed woodpeckers.
Unfortunately, the future of boreal birds in the Adirondacks looks bleak. Global warming threatens to drive all of them out in this century. How fast this might happen is unknown; it will depend, in part, on how rapidly and how much the planet heats up.
Most of the Adirondack forest is dominated by hardwood trees, such as sugar maple, yellow birch, beech and oaks. But at high elevations and in cool, moist lowlands, conifers such as balsam fir, spruce and tamarack are predominant. These trees constitute the Park’s boreal forest, a name derived from Boreas,
the Greek god of the north wind. It’s the habitat of the boreal species. Farther north, in Canada, this type of forest is widespread. In the Adirondacks, the boreal forest exists mostly in the High Peaks and in the Park’s northwestern quadrant.
Climate-change models predict that the average temperature in the Adirondacks will rise 4.5 to 10 degrees Fahrenheit by the end of the century, according to Kent McFarland, a conservation biologist with the Vermont Center for Ecostudies, which monitors the Bicknell’s thrush and other boreal species.
In such a climate, he said, the boreal forest will perish or dwindle to a fraction of its present size, and as a consequence, the boreal birds will leave entirely or, at best, linger in small pockets of habitat.
McFarland said the boreal forest may endure for a while in warmer temperatures, but as the conifers stop reproducing, they will be replaced by hardwoods. “We’re assuming there will be a lag, but we don’t really know,” he said.
It’s also uncertain whether boreal birds will stay during this transition or flee to higher latitudes. McFarland said it’s possible that some species, such as the two boreal woodpeckers, will thrive temporarily as the boreal trees die, providing habitat for insects.
“I foresee some sticking around and perhaps prospering in the short term,” he said. “I think in the long term, they’re done.”
There are signs that the Adirondack climate is changing already. A report issued by the Wildlife Conservation Society, which maintains an office in Saranac Lake, notes that the region’s average winter temperature has risen 5 degrees from a century ago, that lakes freeze later and thaw earlier than in the past, and that snowfall in some locales has decreased significantly.
Michale Glennon, an ecologist with the society, believes climate change already is affecting boreal birds. For instance, some spring migrants are arriving on their breeding grounds earlier than usual. Since their arrival often is timed to coincide with the hatching of insects or larvae, she said, the disruption in the natural order could make it more difficult for them to find food.
What’s more, many boreal birds face serious threats in addition to global warming, such as acid rain, mercury pollution, and the destruction of habitat on both their wintering and breeding grounds.
Jeff Wells, an ornithologist with the Boreal Songbird Initiative, which is based in Seattle, said a million acres of boreal forest is cut down in Canada every year (and in Russia, the pace of cutting is much faster). He believes Canadian logging is partly responsible for dramatic drops in the numbers of boreal chickadees, evening grosbeaks and some other northern species.
Logging in Canada can affect Adirondack birds, Wells said. The Park’s boreal birds are isolated from populations to the north. As loggers cut the boreal forest in southern Canada, they drive the birds there farther north, further isolating the Adirondack populations. The more isolated a population becomes, he said, the more it is vulnerable to disease, natural disasters and genetic deficiencies.
Although data are scarce, several boreal species in the Adirondacks seem to be in decline already. As often as not, the extent of the decline and its cause can only be guessed at.
One starting point for assessing the status of boreal species is The Second Atlas of Breeding Birds in New York State. For this monumental work, hundreds of birders fanned out across the state over five years (2000-05) to learn what birds could be found where. The second atlas compares the recent results with those 20 years earlier (from 1980-85). The Explorer examined the data for 18 species that dwell in the boreal forest and found that nine were seen less frequently during the fieldwork for the second atlas. The other nine were seen more frequently.
Why would some appear to be declining and others increasing?
“That’s a really tough question that I’m not sure anybody has the answer to,” Glennon said.
Kent McFarland cautioned that few conclusions can be drawn by the population snapshots provided by the atlas. “Your sample size is two—20 years ago and today,” he remarked.
The problem is that there isn’t much else to go on. Both the Wildlife Conservation Society and the Vermont Center for Eco-studies are conducting surveys of boreal birds, but these studies are ongoing and have yet to provide a clear picture of what’s happening.
In what follows, the Explorer takes a closer look at several of the Park’s boreal species, drawing information from the atlas as well as other sources. The second atlas divides the state into 5,333 breeding blocks, each nine miles square. For each species, we indicate how many blocks it was found in and the change this represents from the first atlas.
Blocks: 12. Change: -63%
The bay-breasted warbler experienced the biggest decline of any of the boreal birds, mirroring a national trend. The bird is on the National Audubon Society Watch List. It faces threats from deforestation on its wintering grounds in Panama and South America and from clear-cut logging on its breeding grounds in Canada.
This warbler, which breeds in mature conifer forests, was never common in the Adirondacks. Volunteers for the second atlas found it in only 12 blocks (all inside the Park), down from 32 blocks in the first atlas—a 63% drop. Breeding was confirmed in just one location: the Flowed Lands in the High Peaks Wilderness in 2000.
The atlas notes that the bay-breasted’s population rises and falls with outbreaks of the spruce budworm, one of its main food sources. The warbler’s population has declined nationwide since the last major outbreak, which ended in 1985.
Three other of the Park’s boreal birds are spruce-budworm specialists: the Cape May, blackpoll and Tennessee warblers. The Cape May and blackpoll experienced declines of 22% and 8%, respectively, while the Tennessee saw a 4% increase.
Blocks: 316. Change: -34%
The Park’s roster of boreal birds includes two flycatchers, the olive-sided and the yellow-bellied. The olive-sided flycatcher is on the Audubon Watch List. Its population has been decreasing throughout its range since the 1960s, perhaps as a result of logging in Canada and deforestation on its wintering grounds in Latin America.
In New York, the flycatcher breeds primarily in and around the Adirondacks, nesting near mountain ponds, bogs, swampy shorelines, marshy streams and beaver meadows. The amount of breeding habitat in the region probably hasn’t changed much, yet the number of blocks where the bird was found dropped 34%, from 479 to 316.
Birders have noticed the decline. “I’m still seeing them in places, but they’re just harder to come by,” said Sean O’Brien, one of the region’s most avid birders.
In contrast, the number of blocks where atlas volunteers observed the yellow-
bellied flycatcher increased 42%, from 192 to 273. Most of the additional blocks were in the Adirondacks and Tug Hill; it was seen in fewer blocks in the Catskills.
AMERICAN THREE-TOED WOODPECKER
Blocks: 15. Change: -32%
The American three-toed is one of two boreal woodpeckers residing in the Park. The other, the black-backed woodpecker, is much more common. The three-toed was seen in just 15 blocks, a 32% decline from 22 blocks two decades earlier. The black-backed was seen in 127 blocks, an 11% increase.
Since the two woodpeckers share the same habitat—mainly spruce bogs and high-elevation spruce-fir forests—it’s a mystery why one went down and the other up. However, the atlas says the ratio of three-toed to black-backed woodpeckers appears to have been going down for decades.
The three-toed woodpecker is one of the rarest boreal birds in the Park. Birders often look for it at Ferd’s Bog near Inlet, but the woodpecker also has been seen in recent years along the outlet of Osgood Pond.
“They’ve never been real common here,” O’Brien said. “The only one I’ve seen was in Alaska.”
Blocks: 20. Change: -26%
The spruce grouse is one of the most endangered boreal birds in the Adirondacks. As reported in the January/February issue of the Explorer, the state is considering augmenting the local population with birds from out of state.
The number of spruce-grouse blocks dropped 26%, from 27 to 20. Historical data suggest that the population has been in decline for a century, owing largely to logging in spruce-fir forests. The spruce-grouse habitat that remains is fragmented, which raises a question about the bird’s long-term survival here. “They disperse by walking,” Michale Glennon said, “so can they actually get from one patch to another?”
Glenn Johnson, a spruce-grouse researcher, thinks there may be fewer than a hundred of the birds left in the Adirondacks. Without an introduction of birds from elsewhere, he says, the population may die out. The state also is looking at manipulating woodlands to create more habitat for the grouse.
Blocks: 117. Change: -23%
The rusty blackbird has suffered “severe population declines” throughout its range since the 1960s, according to the National Audubon Society, which put the bird on its Watch List. The national trend holds true in New York, where the bird breeds mostly in the Adirondacks. The second atlas reports a 23% drop in blocks, from 151 to 117.
The reason for the decline is unknown, but habitat loss and lethal control in the South, where blackbirds are considered pests, are likely factors. Moreover, because the bird often breeds near inaccessible bogs and swamps, its population is hard to monitor.
Brian McAllister and Sean O’Brien both say the rusty blackbird has been harder to spot in recent years. “I used to find them in several areas, like Madawaska Pond,” McAllister said. “We once found 12 or 13 of them there, and now we go out there, and we don’t see a one.”
Blocks: 138. Change: +12%
The boreal chickadee is a year-round resident of the Park. It can be distinguished from its ubiquitous cousin, the black-capped chickadee, by its brown crown. The boreal breeds in spruce-tamarack swamps and high-elevation forests. In winter, it often can be found in flocks of black-capped chickadees.
The population seems stable in New York state. The boreal chickadee was observed in 138 blocks, a 12% increase from 123 for the first atlas. Although the bird is regarded as an Adirondack specialty, it also was sighted, for the first time, in Tug Hill during the atlas fieldwork.
McAllister has no trouble finding the boreal chickadee near his hometown of Saranac Lake, at such places as the Bloomingdale Bog and the Chubb River. “Whenever I’m out in their habitat, I generally do hear them or see them,” he said. “I don’t think there’s any major decline going on.”
That’s in the Adirondacks. Throughout its range, the boreal chickadee has declined 73% over the past 40 years, according to Audubon. The organization attributes this to logging, drilling and mining in Canada as well as deforestation from fire and insect outbreaks. Because the chickadee remains numerous, Audubon has not added it to its Watch List.
Blocks: 114. Change: +20%
The gray jay is another year-round resident and a favorite of Adirondack birders. Nicknamed the “camp robber,” the gray jay is not shy about approaching humans for food. It’s not unusual for a bird to land on an outstretched hand for a morsel.
This jay dwells year-round in the lowland boreal and subalpine forests of the Adirondacks. The second atlas reports that it was found in 114 blocks, a 20% increase from 95 blocks 20 years earlier. Its population appears stable throughout its range (it lives mostly in Canada and Alaska).
Nevertheless, there are concerns. Michale Glennon, of the Wildlife Conservation Society, pointed out that gray jays cache nuts and berries, food they rely on during winter. If global warming brings more frequent or longer thaws, their food could spoil.
Blocks: 57. Change: +46%
Audubon regards the Bicknell’s thrush as one of its top conservation priorities, owing in part to its limited range. The bird breeds only on high mountains in the Catskills, Adirondacks, New England and southeastern Canada.
About 90% of its breeding territory is in New York and New England—all of it at risk from global warming. “Under the most likely scenario, there’s not going to be any of this habitat left,” said Kent McFarland of the Vermont Center for Ecostudies. “There might be a speck of it on Mount Washington” (the Northeast’s highest summit).
Most of the forest on the bird’s wintering grounds in Haiti and the Dominican Republic already has been destroyed by logging and clearing for agriculture.
The 46% increase in observations of this reclusive thrush is an anomaly. The Bicknell’s was not identified as a distinct species until 1995, which set off a rush among birders and scientists to find it. With more people looking for the thrush, more of them were sighted. The bird was found in 57 blocks, up from 39. Researchers from the Vermont Center for Ecostudies contributed data for 27 of the 57 blocks. In reality, McFarland said, there is no evidence that the bird is on the increase. The one long-term study, conducted in New Hampshire’s
White Mountains from 1991-2001, showed an annual 7% decline.
Blocks: 43. Change: +4,200%
Despite its name, the palm warbler is a bird of the far north. It’s estimated that 98% of the birds breed in Canada. During fieldwork for the first atlas, the bird was observed in only one location in the entire state, at Bay Pond Bog west of Paul Smiths. For the second atlas, volunteers found it at 43 locations—a 4,200% increase!
Nearly all the sites were in the Adirondacks, where the bird nests in boreal bogs. Kimberly Corwin, one of the editors of the atlas, cannot account for the dramatic rise in population. “What’s changed with the bogs, we don’t know,” she said.
Data suggest that the bird’s population has been rising in Vermont and Maine as well. Perhaps because its habitat is so remote, the bird is doing well across its range.
Brian McAllister saw his first palm warbler along the Boreal Life Trail at the state-run Visitor Interpretive Center in Paul Smiths in 1998. “It was a bit of excitement for me,” he said. Since then, he has spotted it many times. “In all the right habitat, it’s almost guaranteed to be seen.”
The gravest threats to boreal birds originate outside the Adirondacks: global warming and the destruction of habitat, both on wintering grounds and in the vast swath of circumpolar boreal forest. Nevertheless, environmentalists say New York state can do its part by protecting the birds and the remaining boreal habitat in the Adirondacks.
Of the birds discussed above, only the spruce grouse is on the state’s list of
endangered species. The Bicknell’s thrush is listed as a species of special concern. John Sheehan, the spokesman for the Adirondack Council, said the state should do a better job monitoring boreal birds and, if necessary, add others to the endangered list.
Most of the Park’s high-elevation boreal forest is safe from development, being part of the forever-wild Forest Preserve. But the lowland boreal forest remains largely in private hands. The Council has proposed creating a 73,300-acre Boreal Wilderness in the northwestern Adirondacks. This would require the purchase of more than 55,000 acres of private land. In addition, the council is proposing a 185,000-acre Low-Elevation Boreal Heritage Reserve, containing both private and state land. The reserve would include the Boreal Wilderness.
The private land in the reserve would be protected by conservation easements that permit ecologically sensitive logging but prohibit development.
“The habitat is crucial to the survival of several species, including boreal birds,” Sheehan said. “It is the best habitat we have for some of our most charismatic fauna, including the moose and the Canada lynx.”
Sean O’Brien goes further, arguing that the state should restore much of the boreal forest that loggers have cut down since the 19th century. “Plant more tamarack and balsam and spruce,” he said, “and get rid of some of the other stuff.”
That may sound like a far-fetched idea, but the state Department of Environmental Conservation already is manipulating a patch of forestland in the northwestern Adirondacks to try to improve habitat for spruce grouse. The experiment is on private land, since state law forbids the cutting of trees on the state Forest Preserve.
Some may wonder what’s the point. If the Adirondacks is going to heat up, can any of its boreal forest be saved in the long run?
Jeff Wells thinks it possible. The computer models, after all, are not infallible. There may be time yet to curb global warming. “We should be careful not to get a sense of fatalism,” he said. “We shouldn’t just give up. We can do something about it and ameliorate the impacts.”