Loons may be common, but still need our help to thrive
With the retreat of ice comes the return of waterbirds, among them a black-and-white flecked beauty that is perhaps the most revered and emblematic of Northern species.
It is certainly the most audible on a calm summer night, its unmistakable cry pinging back and forth across the lake — sometimes like a laugh, other times like a lament, or as the poet Ted Hughes described it: “As if the sky were trying to die.”
Loons themselves are still very much alive in these parts, thankfully, although their ongoing presence should not be taken for granted.
“I can list a dozen species of birds that used to be common that you don’t see as much anymore,” says Kathy Jones, volunteer coordinator with Bird Studies Canada. “Barn swallows, chimney swifts, woodcocks — species we all enjoy that are no longer as prominent.”
There are five species of loon on the continent but our version — the common loon, of course — is the only one found south of the Arctic and east of the Pacific, and the one whose likeness, with its signature necklace, appears on the dollar coin.
Lakes around Sudbury have improved significantly in the last few decades from the impact of acid rain and other industrial stressors, which has in turn helped loons find the food and habitat they need to thrive, but data has also shown their reproductive rate has declined in the last 30 years.
Jones says there isn’t one simple explanation for this trend but a variety of factors are likely at play.
“We know we still have an impact with chemicals in our lakes, with acid sensitivity and mercury and other toxins,” she says. “We still have impacts decreasing productivity in our lakes, with fewer fish available, and hardened shorelines and fewer nesting sites.”
For nearly 40 years, Bird Studies Canada has coordinated a survey that relies on volunteers to monitor the presence of loons on lakes and report on the birth and survival of chicks. It was launched in Ontario in 1981 and expanded across Canada a decade later.
Among those pitching in locally are survey veterans Marlies and Dieter Schoenefeld, who have paddled a variety of Sudbury lakes, binoculars on board, since the earliest days of citizen science effort.
“They were actually part of the committee that organized the first loon survey in Ontario,” Jones points out.
More volunteers are now required, however, to provide a more complete picture of population health.
“We’re just trying to fill in the gaps,” says Jones. “We have a 40-year Loon Survey Report coming up that we want to analyze the data for, and it just makes it that much better if we can have a few more gaps and historical sites filled in.”
Already there are more than 6,000 lakes in the database, but bringing new loon trackers on board may also mean a lake that hasn’t been documented as hosting a pair before may, well, surface.
“Finding a new lake is unusual, but it does happen,” says Jones.
Many Sudbury lakes have already been studied and continue to be monitored by volunteers, but there are some surprising holes on the map. Ramsey Lake, for instance, currently does not have a volunteer loon watcher, nor does sprawling Panache, which hosts multiple pairs. The relatively tiny Hannah, off the southwest bypass, could also use someone to spy on the species.
Volunteers need not be expert birders, nor do you have to go out daily to check on the behaviour of the stylish swimmers (and expert divers).
“The reality is we only need three well-timed surveys,” says Jones.
Participants are asked to check out the loon activity on their lake just once in June (to see if a pair is present), once in July (to see if chicks hatch) and once again in August (to see if chicks survive long enough to fledge).
“What we’re looking at is reproductive success, so the number of chicks that hatch on the lake,” Jones says. “It’s an index of how well they are producing young to maintain the population.”
For many, the work wouldn’t be much different from what they already do for enjoyment, the Bird Studies Canada rep notes.
“If you know Canadians, we love our loons,” she says. “That’s just a given, right? So often it’s something people are doing anyway, and we just ask them to share the data.”
An ice-out connection to breeding success?
Collecting data on loons in the Sudbury area is something Ottawa-based biologist Robert Alvo has been doing, largely by canoe and often alone, since an earlier Trudeau held the keys to Sussex Drive.
“I started it in 1982 for my master’s thesis,” he says. “I surveyed 84 lakes originally, and later bumped that up to 94, all in the Sudbury region.”
At that time many of the lakes he was looking at had been rendered nearly lifeless due to mining emissions.
“Fish species start to disappear below a pH of 6, and at 4.4 there’s no more fish,” he says. “I found lakes at 4.0, so definitely no fish, and also an absence of a bunch of other food types for loon chicks.”
Alvo would return, year after year, to check on both the acidity of the lakes in his study area and the ability of loons to withstand or work around these conditions, publishing his findings in a 1988 paper, as well as one in 2009 that drew on 25 years of data.
“The first publication showed that loon breeding success is inversely related to acidity, so the more acidic the lakes, the less success they had,” he says. Loons would either avoid the lakes altogether, he found, or not find enough food to sustain their young.
By the time of the 2009 report, many of the lakes had rebounded considerably in terms of pH levels, and continue to do so now, but reproduction has been inconsistent from year to year and lower overall than would be ideal.
“The lakes are coming back slowly, at least chemically,” Alvo says. “The lakes that were around 4 are now around 5, which is a big difference biologically. But productivity still varies from one year to another.”
In 1996 reproduction was particularly low, as was the case again just this past year, when Alvo returned after a 10-year absence to sample about half the lakes in his original study area. (He would have done more, but had to call it off after developing a sore paddling arm.)
While there could be a number of factors for this, the biologist is intrigued by the fact that both 1996 and 2018 were years when lakes didn’t fully open up until well into May.
“My working hypothesis is the low reproduction has to do with a late ice-out,” he says.
Theoretically loons would still have enough time, even in a year of late-leaving ice, to nest and hatch offspring, he says, but “one of the arguments is the females need more time to fatten up after migration before they can lay eggs.”
Alvo now hopes to explore this question further, as well as others concerning loon health, through a collaborative project with Bird Studies Canada and Acadia University.
Beginning this summer, Kristin Bianchini, a post-doctoral researcher, will be carrying on Alvo’s fieldwork, looking at the same set of lakes near Sudbury to assess how well loons are recovering from acid rain, mercury and cottage development.
“We’ve determined the pH is increasing but we want to find out how loons respond and how the biota in these lakes responds,” Alvo says. “It’s one thing to increase the pH but it doesn’t necessarily mean loons are going to start doing well right away. It depends on everything between the pH and the loons, which is the food — how long does it take the fish to come back? What about the non-fish stuff the chicks eat? How long does it take for the lake to heal biologically?”
Adored species has a few surprising traits
Loons may be beloved creatures but they are also perhaps over-romanticized, or at least misunderstood, in a number of ways.
It was long assumed, for instance, that they mate for life, but, as Alvo puts it, “that bubble was burst about 15 years ago.”
Turns out a loon that is evicted from its territory, or loses a mate to death, will often pair up with a new squeeze. A few loons will even cheat on a spouse.
“Some researchers in the U.S. found examples of out-of-marriage mating,” says Alvo. “They’re generally monogamous, even from year to year, but it’s not 100 per cent clear-cut.”
Another myth is that a pair of loons will only keep to one lake. Alvo says he’s personally watched a pair on Wolf Lake, northeast of Sudbury in the Chiniguchi area, forage on nearby Silvester Lake.
Loons were also originally felt to be too wild, and delicate, for capture and banding, but researchers have now found they can not only get coloured strips around their legs but “can take blood and get DNA samples,” he says.
Banding for gender (males and females have the same markings so are almost impossible to tell apart visually) has also led to other surprises, such as “one of the vocalizations only being done by males, as a territorial thing,” says Alvo. “That wasn’t known before.”
And if you thought they were sweet, peace-loving creatures, you might have to adjust that impression, too.
“When a male flies over a lake and calls, he’s actually signalling certain information, like I’m big and ready for a fight for territory,” Alvo says. “And some of these fights end up in murders.”
Occasional proclivity to killing and two-timing notwithstanding, these birds do have some very endearing qualities.
A mating pair builds its nest together, for instance, and jointly incubates the eggs. If you are not already going “aww,” mom and dad will also take turns carrying the chicks on their backs.
“They do that to prevent predation and hypothermia,” says Jones.
Jones says loons are “notoriously good at arriving as soon as the ice goes out” — although they don’t start mating until May — and have eyes that turn a brilliant red in summer before fading in the fall.
But while they are fabulous divers and swimmers, they aren’t so great on land, or taking off, which is why you often see them galloping across a lake to become airborne.
“A lot of people don’t realize loons can’t walk,” says Jones. They don’t even waddle, she says, but rather do “a kind of shuffle thing.”
This lack of terrestrial mobility means they nest quite close to the water, which makes them vulnerable to sudden changes in water levels.
Loons are faring pretty well these days in Northern Ontario — unlike parts of Europe and the U.S., where they are considered at risk — but more needs to be done, says Jones, to improve biodiversity and ensure loons have the habitat they need to sustain themselves and their offspring.
“It’s an iconic species that represents the quality of our lakes,” she says. “If we know we have them, we know the lakes are in a bit better shape. It all ties back to keeping a healthy environment and our lakes as natural as possible.”
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