Where the big birds breed:
Reversed flow
We were in Burns Lake, taking off on the first of six long days of helicopter flying, documenting every osprey and bald eagle nest in or beside the entire Nechako reservoir. As we gained altitude and flew south over the Lakes District, we reviewed the reservoir’s history.
This huge expanse of water was created in the early 1950s when Alcan flooded a series of lakes and rivers in the BC interior, forming a huge reservoir to supply hydroelectric power for its new aluminum smelter at Kitimat. It was, at the time, the largest water-diversion project in BC’s history.
By building the Kenney dam, the flow of the Nechako River was reversed from eastward to westward. Water that used to flow down the Nechako into the Fraser, and south to Vancouver now plunges through a huge tunnel—16 km long and as wide as a two-lane highway—under the Coast Mountains at the reservoir’s far western edge. Dropping 800 metres in elevation and emptying almost directly into the Pacific Ocean, the torrent turns Alcan’s massive electric generators at Kemano as it courses past. The new lake that was created is nearly 400 kilometres long, counting its various arms, or “reaches.”
Consistent with the prevalent social and environmental ethics of the era—and the provincial government’s sense of urgency to develop the province’s resources quickly—there were a number of problems resulting from the massive project. The water was already rising, for instance, when the Cheslatta First Nation was informed that the land it inhabited, including burial grounds, would soon be submerged. White settlers and their homesteads were displaced as well.
But what brought Ruth and me here to count osprey and eagle nests was the fact that many thousands of hectares of unlogged forest were also flooded, resulting in vast areas of submerged and partly-submerged trees. While being extremely treacherous for boating, these dead trees, or snags, are ideal nesting sites for ospreys.
Sometimes called “fish hawks,” ospreys are very large, fish-eating birds that build platform nests—broad, flat constructions of branches, twigs, and other debris—as close as they can to the water. Or, where possible, they will build right over the water, safe from nearly everything—except, perhaps, biologists in helicopters.
Flooded landscape
As we crested the ridges on the north side of the reservoir and began our descent toward the water, we could see the eerie, silver-grey spires rising from the lake by the thousands: the tops of dead forests. Here and there were islands—all that remain visible of former riverside hills. As we came closer, we could make out dark clumps in the tops of some of the dead and broken trees; these were the osprey nests.
We began our surveying immediately. Flying along the lakeshore or over vast areas of snags, we all watched intently for nests. When one was spotted, the pilot took a GPS reading, I took photos of it, and Ruth assigned each one a number and recorded the information in her log, noting whether or not it was occupied. A simple, efficient system, it seemed—until we found ourselves wheeling around in dizzying circles over a seemingly endless sea of dead trees supporting quite similar-looking nests. In time we became accustomed to the process and proceeded with less confusion.
The high density of nesting habitat in the reservoir has resulted, over the past 50 years, in an unusually high density of breeding ospreys—the highest in the world, in fact. This might never have amounted to anything more than a curiosity except that the Province, in its perpetual quest for more timber, realized that the wood that was underwater was still in quite excellent shape. While the above-water portions are gradually decaying, the absence of oxygen below the surface has preserved the wood there.
Since it was clear that sending scuba divers with chainsaws to the lake bottom was not reasonable, underwater logging equipment was developed. However, all these tree-top osprey nests could not just be cut down, leaving the birds “homeless.” Before logging plans were approved, a strategy to manage the osprey population had to be devised. But how many nests were there, actually, and how many were being used?
This is where we came in. Ministry of Environment ecosystem specialist Anne Hetherington, with funding from Forest Renewal BC, administered an osprey nest inventory with follow-up “on-the-ground” observations. Biologist Ruth Lloyd was contracted to do the fieldwork, and asked me to be her assistant and photographer for the aerial survey.
Day after day we flew along the endless perimeter of the reservoir, following the shoreline as it wound in and out of coves, marshes and inlets, and around the numerous islands. We flew up creeks and around rocky promontories where eagles were nesting in giant old cottonwoods and ancient, gnarly pines. When a nest was spotted it was necessary to circle around it in order to get a proper bearing, take photos, and observe any occupants. Some nests contained osprey or eagle chicks, some contained eggs not yet hatched, and some were not being used that year. The nests numbered in the hundreds. The days were long, and occasionally a little woozy.
Emergency landing
By now Ruth was a full eight-and-a-half months pregnant. The pilot still looked on anxiously as he watched her clamber determinedly into the helicopter each morning…and he heaved a sigh of relief when we returned safely to the base in Burns Lake each evening.
Ruth was unperturbed. “As far as I’m concerned,” she told me privately, supporting her huge tummy with both hands, “we’re flying around in the best ambulance there can be. Any problems, and we’ll get to the hospital in record time!”
While I was not exactly worried, I do know that any machine can break down at just about any time—and it was not hard to imagine having to make a forced landing in the very remote and roadless country we were flying over, beyond radio contact, in the heart of the BC interior. If we were stuck out there, and Ruth’s baby decided that right now was the time to enter the world, a broken-down helicopter would not do us much good.
But I was at least a little prepared. Before leaving home to join this expedition, I had put together an emergency birthing kit: sterilized sheets, scissors, string, blankets, etc…all sealed and stored in its own separate pack. As a veteran of three home-births, I could at least visualize the process—barring complications.
And then there came a day when the helicopter actually did have to make an emergency landing. As we came down, the pilot radioed our location and what he figured the problem was. Fortunately for all, we landed along the small portion of the reservoir with road access—so we had to wait only a few hours for the mechanic to arrive with a new part.
Later that day, perhaps feeling a little fatigued, Ruth suddenly asked, “Paul, what the hell do you have in that extra pack we’re always loading and unloading?” She still guffawed a bit dismissively when I answered her—but at least there were no more complaints about my extra bag.
The rest of the story
During a subsequent summer, Ruth and assistant Jim Williamson conducted ground-based observations on a number of osprey pairs (see “Ospreys with attitude”).
The study results were utilized in the underwater-logging plans developed for the reservoir. According to John Gerow at the Nadina Forest Service office, some areas of particularly high-density nesting have been deferred from logging. Everywhere else there is a 200-metre no-cutting zone around nests during the breeding season, and a 60-metre buffer the rest of the year.
Harvesting of the underwater trees began in 1996. Recently the amount of underwater logging has tapered down to almost nothing due to the glut of beetle-affected pines currently being salvaged. The trees in the reservoir are waiting patiently, and will still be in perfect condition when the pine logging subsides. Gerow says that there are an estimated six million cubic metres of usable wood beneath the water.
As the above-water portions of the snags in the reservoir decay over time, or are logged, the amount of osprey-nesting habitat will gradually decline. To offset this, 65 artificial nesting platforms have been erected to date in the reservoir, sponsored by Alcan, with another 240 planned for the next two years. The ospreys seem to readily accept these new quarters; the occupancy rate is quite high.
Ruth’s daughter Tirion was born about two weeks after we finished the helicopter survey of the reservoir. She has little interest in birds, and—after recently assisting her mother for a day during another aerial survey—is now avoiding small aircraft.