“It’s shocking,” says Bill Montevecchi, a biologist at Memorial University who describes it as one of the strangest events he has witnessed in his more than 30 years studying the seabirds. But, then, so too was the sea water near the colony that was several degrees Celsius above normal in August and appears to have triggered the abandonment.
It could be a harbinger of things, say scientists at the Audubon Society who have made the bold prediction that climate change could “imperil” nearly half of North America’s birds by the end of the century.
“It’s not so much that the adults are just going to die, but that they’ll not be able to successfully raise enough young to replace themselves over succeeding generations,” says biologist Gary Langham, lead author of Audubon’s grim forecast.
It lists the northern gannet — along with the common loon, bald eagle and mallard duck — among 126 “climate endangered” species that could lose more than 50 percent of their current “climatic” range by 2050.
Conservation groups say the report, released Sept. 8, underscores the need to cut greenhouse gas emissions and conserve bird habitat.
“The refugee birds that come up from the deserts that are going to form in the central United States, they need to have somewhere to go,” says Ted Cheskey, Nature Canada’s manager of bird conservation. He says only a third of Canada’s important bird areas now have formal protection.
Jeff Wells, lead scientist for the Boreal Songbird Initiative, says the study shows Canada’s forests ”will only continue to grow in terms of importance as more and more birds are forced north as climate change continues to heat up.”
But some scientists are critical of the Audubon campaign and its sweeping predictions, saying it is masterful marketing but sketchy science.
André Desrochers, a wildlife biologist and avid birder at Laval University, says the mallard projection is “totally nonsensical.”
“The mallard has increased by an order of magnitude in the last few decades — it’s totally adaptive to all kinds of impacted habitats,” Desrochers says.
He says Audubon’s projections for birds seen in Quebec are “full of holes” and “point to a very sloppy job.”
Audubon’s “climate report” is a website with interactive maps predicting how “314 species on the brink” will be doing in 2020, 2050 and 2080, along with arresting pictures and a fund-raising link so people can donate “to give birds a fighting chance in a warming world.”
Langham says people will be able to put the estimates to the test by tracking birds across the continent and seeing how reality compares with the predictions in 2020.
“I’d be the first one to celebrate if the model is wrong but the bird is OK,” Langham tells Postmedia News.
In coming months he says Audubon plans to publish three science reports elaborating on out how his team determined the “climate space” for the 126 climate-endangered and 188 climate-threatened birds.
They looked at 17 variables including temperature, precipitation and habitat for the different species and then modelled how their ranges would shift as the climate changes.
“It’s clear that many of the birds that are currently breeding or wintering in the lower 48 states of the U.S., their climate space is shifting dramatically into Canada, and deep into Canada in many cases, “ Langham says.
The change is already underway with 61 per cent of North American birds shifting their range northward during the past 40 years, he says.
Birders are delighted to see the new arrivals such as the Mississippi kite spotted in Winnipeg this year, the white-faced ibis colonizing lakes in southern Alberta and Saskatchewan, and the prothonotary warbler showing up in Regina.
“It was extraordinary as it was 800 kilometres out of its normal range,” says Cheskey, at Nature Canada, who saw the wayward warbler flitting around trees near Regina’s Wascana Lake in May.
At the more southern edges of birds’ ranges, there are signs of the breeding failures Langham expects to accelerate.
In Southern California’s Orange County this year owls and hawks are reported to be having their worst breeding season on record. “Most of the nests are fledging zero young,” Langham says.
“It’s not hard to imagine” the breeding failure is tied to California’s record drought this year, he says, and that the adult birds can’t find enough food for their young.
Another recent failure, which Langham says was “definitely climate related,” involves Atlantic puffins off the coast of Maine, which the Audubon has been monitoring for 41 years.
The puffins are doing well this year, but he says they had low breeding success in 2012 and 2013 because warm ocean currents dramatically altered the type of fish near their colonies. The hungry puffins started bringing butterfish to their young, which were too big for the young birds to choke down.
One of the chicks starved to death on camera. ”It was very traumatic,” Langham says.
Similar scenarios appear to be playing out with the northern gannets, which winter in the Gulf of Mexico and breed at six colonies in eastern Canada.
“These birds really are like Olympians,” says Montevecchi, noting how the diving seabirds have two-metre wingspans and will fly more than 100 kilometres to find fish for their young.
The biggest colony of close to 200,000 gannets is on Bonaventure Island off Quebec’s Gaspe, while the most southerly colony at Cape St. Mary’s on the south coast of Newfoundland has about 25,000.
The gannets feed mackerel and other oily fish to their chicks, which in good years grow into fluffy “fat balls,” Montevecchi says.
But in 2012, the surface sea water was three to four degrees warmer than usual and appears to have forced the gannets’ preferred fish either farther offshore or into colder, deeper waters, with disastrous consequences for the birds.
“Gannets can dive only 20 metres deep, so any fish below that is essentially non-existent to them,” Montevecchi says.
It was so bad in 2012 that only eight per cent of the nests that researchers monitored on Bonaventure Island fledged a chick. Chicks were seen begging their parents for fish they didn’t have. Gannets were spotted more than 500 kilometres from their colonies. They were also seen diving within a metre of fishing boats for fish and shrimp being washed overboard.
Even more extraordinary, on August 8, 2012, the adults on Cape St. Mary’s abandoned their nests en masse — something that has never seen before.
“It was like a switch had been flipped,” says Montevecchi, part of the team that investigated the “extreme, unprecedented event.”
Montevecchi says nest abandonment this year was not as sudden or as extreme as 2012, and appears to be restricted to Cape St. Mary’s.
But in mid-August the adults began leaving and over two to three weeks as many as 35 to 70 per cent of the chicks were left to fend for themselves. The trigger for the abandonment again appears to be sea water several degrees above normal. Montevecchi says there are plenty of unanswered questions about the oceanic and climate forces driving the warm water and if such “perturbations” are becoming more frequent.
Montevecchi says Cape St. Mary’s gannets have now returned to their nests, but many chicks perished. He estimates breeding success will be less than 50 per cent when the young leave their nests by the end of September.
Like Desrochers, Montevecchi is troubled by some of Audubon’s “over the top” predictions that he says seem designed to attract media attention. But he also says there is “no question” climate change is impacting birds and needs to be tracked more carefully.
“This is very real,” he says of the gannets’ nest abandonment.
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