Woodpecker of the Boreal Forest

Woodpecker of the boreal forest

I live at the southwestern edge of the Northeast Kingdom in Vermont. What makes it a “kingdom”? I’m no sure. Perhaps I can report on that in some future essay. But most naturalists recognize that boreal forest is the distinctive characteristic of this part of the state. The Kingdom is not pure boreal forest – rather, it occurs in patches where conditions are favorable. But those patches are particular to the northeast.

For birders in Vermont, there are four reasons to spend time in boreal forests: Canada Jay, Spruce Grouse, Boreal Chickadee, and Black-backed Woodpecker. Their distribution in Vermont is limited to the northeast. (Of course, we could also venture to northern New Hampshire to find all of these more easily, but that means invading the Kingdom of tax dodgers, a distasteful prospect.) The single best place for them in Vermont is Moose Bog, a small state Wildlife Management Area, which has achieved legendary status since many birders manage to check off the Boreal 4 on their annual lists there.

Trees of the boreal forest

I’ve learned a lot about Vermont’s forests from Charles W. Johnson’s 1980 book  “The Nature of Vermont.” Johnson states that boreal forest “is technically defined by the predominance of spruce and fir…. Red Spruce and Balsam Fir are the climax species,” with Paper Birch being a “subordinate companion.” Where the topography allows, water pools into bogs, and Black Spruce and White Spruce join the party, with scattered White Pines that can grow very high (as British ship builders discovered in the 1700s). Sphagnum mosses can cover much of the ground that is not permanently wet.

This particular combination of tree and plant species combines with snow depth and winter temperatures to create good conditions for the Boreal 4 in the Northeast Kingdom. This image of ranges of the four species, which I have extracted from eBird.org, shows how the species favor the northeast corner of the state. Ted Murin and Bryan Pfeiffer, in their 2002 book “Birdwatching in Vermont,” summarize the biogeospatial* overlap of species by stating, “At any time of year the Northeast Kingdom, resistant to suburban sprawl and wary of popular culture, is not only a place for solitude but also home to boreal species found nowhere else in Vermont.”

Ranges of the Boreal Four species in Vermont. From eBird abundance maps

In each case of the Boreal 4, there is some leakage into neighboring regions of Vermont. There are a handful of records of Boreal Chickadee in the Green Mountains, for example, although these have not been sustained through time. Being a “Kingdom resident,” then, I have taken special interest in Black-backed Woodpecker, which has found a foothold in a surprising place.

Black-backed Woodpecker in Moose Bog, March

Black-backed Woodpecker in the Steam Mill Brook WMA

Shortly after taking up residence in the northeast, I came across reports of Black-backed Woodpecker at a place far from the well-known Moose Bog. It is a large undeveloped tract owned by the state with the curious name Steam Mill Brook Wildlife Management Area. Comprising 4500 hectares, it has a few small ponds, an expanse of hardwood forest, a trail or two, and no roads. The name sometimes stumps me when I try to describe it to other people, because it seems like three random words, “brook,” “steam,” and “mill” have been stuck together in seemingly random combination. I can only surmise that there was a log mill at one time, probably in the 1800s, that acquired the name “steam mill” early on a winter morning when operating feverishly to produce boards for sale to farmers and local residents. Then the brook feeding the mill must have taken the name, and when state land managers decided in 1971 to take it over for hunting, they used the name of the brook. In any event, I can see the edge of the WMA from my house, and the idea that it harbored one of the state’s rarest woodpeckers took on an air of intrigue.

In recent years, there have been only two places in the Northeast Kingdom where you could reliably find a Black-backed with a reasonable amount of effort: Moose Bog and Victory Basin. (I include the huge Nulhegan Basin of the Conte National Wildlife Refuge with Moose Bog, since they are contiguous with no substantial break in habitat characteristics.) They are nowhere abundant, so a walk in the woods that produces one is a day to celebrate. Moose Bog and Victory Basin are long- established areas for them. But how the heck did they get to Steam Mill Brook WMA?

Sightings of Black-backed Woodpecker in the last five years. From eBird.org

If you got ambitious one day and walked from Moose Bog to Steam Mill Brook, you would find yourself crossing a lot of agricultural land, with patches of hardwood forest riven by creeks and streams. Not the kind of areas for a boreal bird. There is no question that Steam Mill Brook is isolated from the boreal forest patches to the northeast. On the first several hikes into the WMA, I didn’t find anything resembling boreal forest at all. I began to wonder if past reports of the woodpecker here were flukes – wandering birds that were sick and confused. That the birds might never be seen again in this patch.

A portion of Steam Mill Brook Wildlife Management Area

On a pleasant day in mid-May, I wandered around Steam Mill Brook, bushwacking my way near the wetlands in the area’s center. A few hours of effort had yielded some nice warblers: Nashville, C. Yellowthroat, N. Parula, Magnolia, Pine, Yellow-rumped, and Canada, with tons of Black-throated Green, Black-throated Blue and Ovenbird. Together with vireos, most of these birds were setting up territory, darting between memorized tree branches to facilitate a mad scramble at any future interloper. It was a wonderful reminder of the value of healthy hardwood forest habitat in Vermont. But other than the usual tree-clinging creatures (Yellow-bellied Sapsucker, Downy, Hairy and Pileated Woodpeckers), there were none of the boreal type that I sought. Another valiant but fruitless effort, I thought in resignation. The location of the brook in this WMA is at the bottom of a gently sloped area between hills, and the water barely moves at all. It is slightly bog-like, but nothing like Moose Bog or Peacham Bog. I looked around and contemplated future bushwacks in other remote parts of the WMA. I heard a soft “chuck” that seemed to emanate from a small stand of reeds, and thought Red-winged Blackbird  – another one for the day’s list.

I stopped to rest for a few minutes. One of my knees was throbbing. Birding in Mexico a few months earlier, I angled for position to photograph a Strong-billed Woodcreeper, lost my footing, and went down in a heap. A surgeon would eventually inform me that a partial tear in the quadriceps tendon would become a new feature of my biomechanics. On this day, I was starting to think that I had been overly ambitious to take such a sustained bushwack, and that my car was farther from my current position than was probably wise.

I heard another sound somewhere in the trees above. It was the thud of a beak against bark. Maybe another Red-breasted Nuthatch, working away at a pine nut or seed? Then there was movement in my peripheral vision. Now this didn’t seem right. Nuthatches crawl along tree trunks; this was more of a transit flight between tree trunks, and it was too large for a nuthatch. I moved a few steps closer to the base of one tree, and searched through a tangle of branches to the trunk high above. Then I saw the source of the sound. You idiot, I thought – that was not the chuck of a red-wing five minutes ago. It was a black-back!

Working a spruce in the Steam Mill Brook WMA!

The Black-backed Woodpecker has a very distinctive call, a chip note superficially similar to most of the other woodpeckers, but more distinctively like the sound “click.” In dense forest, where I was at the moment, this sound gets muffled, and it can get lost unless you are paying close attention. There was no doubt now: straining my neck to look vertically upward, I was seeing a grayish-white belly with black bars on the flanks. It was roughly the size of a Hairy, but they are not barred. The head was blackish, with only one white stripe from the bill back to the neck. Most of all, that back was one solid stretch of uninterrupted black color! After many hours in the Steam Mill Brook, I finally had my boreal woodpecker.

I managed a few distant photos, but this individual was not being cooperative. The trees here are thick, and a ten-inch woodpecker who calls softly and very infrequently can hide without trying hard. All of my encounters with Black-backs have impressed upon me how secretive they can be. It is a characteristic they share with the closely related species American Three-toed Woodpecker. (The close relationship is emphasized by the old name, Black-backed Three-toed Woodpecker.) I will have to return to the spot to secure a high-quality photo. I also need to map out the extent of the boreal habitat here, which is clearly limited in extent (and maybe in boreal character, too).

Why is there a disjunct population of this species? The fact that they are so hard to find here likely means that there are only a handful at the site. Did young woodpeckers disperse from Victory Basin or Moose Bog and stumble upon an isolated chunk of suitable habitat? I think not. Black-backs are not wandering birds. They are very specific to their habitat type – very local. There are few cases of them showing up in a strange place far from known sites. And finding the Steam Mill Brook WMA would require a huge amount of searching, a seemingly futile effort. A more likely explanation for these individuals is that there was a time in history when boreal forests were more extensive than today. Changes in climate could have led to encroachment of hardwood forest, which the Black-back cannot make use of. The birds in Steam Mill Brook might be clinging to a residual piece of boreal forest, a modern-day relic of an ancient, larger stretch that could have been connected to Victory Basin. These woodpeckers might be similar to desert pupfish in the western deserts, now restricted to caves where the water is fed by rare underground springs, and where they perch on the precipice of extinction.

In this era of the mutilation of natural resource science, principally by policy makers deluded into thinking that forests and woodpeckers have negligible value compared to urban humans who are momentarily out of a job, we must commit ourselves to understanding where boreal forest remains, how it is changing, what it needs to survive, and how its creatures make use of the unique vegetation that it contains.

[* I just made up that word. I’m not sure why it’s not found commonly.]