Warmer Arctic creates nasty surprises for the early birds

Long-tailed ducks flying near one of their breeding islands in the High Arctic are among the migratory birds which may arrive earlier in the North where unfamiliar environmental conditions may put them at risk. (PHOTO COURTESY OF MARK MALLORY, CWS)

About 800 thick-billed murres, shown on their nesting ledges at Prince Leopold Island, died in 2005 when a eroding rock ledge tumbled down on their nesting ground. (PHOTO COURTESY OF MARK MALLORY, CWS)

As Arctic temperatures warm and weather becomes less predictable, migratory birds may face new challenges and some nasty surprises when they return north, researchers with the Canadian Wildlife Service say.

Sometimes birds arrive at their northern breeding grounds earlier than they used to, driven by warm weather in the South, only to find no food there when they arrive.

And, once they’re in the Arctic, increasingly unpredictable weather can cause them another lot of misery.

Due to higher than average temperatures in many parts of Nunavut this past winter, birds are already flocking back to the High Arctic.

In Cambridge Bay, where Environment Canada says temperatures were five to six degrees above normal this past winter, and warm again into March and April, snow buntings have returned — a full month earlier than usual.

This means Canada geese, snow geese and other migratory birds aren’t far behind, hunters say.

But when the birds finally arrive at their destination, their entire breeding cycle could be turned upside down.

That’s because the breeding schedules of these birds may be out of whack with nature and as a result they may lack food for their young.

The birds’ arrival may not follow the same pace of change as the environment, producing what wildlife biologists called a “mismatch”— where wildlife habits change, but the environment lags behind.

Researchers with Laval University have found that high spring and summer temperatures led to fewer young surviving among snow geese on Bylot Island.

And when warming temperatures combined with increased numbers of mosquitoes, they contributed to higher numbers of deaths at some seabird colonies, say biologists with the Canadian Wildlife Service.

Sicne the 1970s CWS biologists have seen severe weather produce many lethal situations for seabirds.

Generally most seabirds are long-lived. Eiders live at least 10 years, murres about 30 years, and fulmars up to 50 years, so “you don’t see them die very often,” said Mark Mallory, a seabird biologist with the CWS in Iqaluit.

But extreme weather appears to be able to knock years off seabirds’ lives, Mallory said.

These extreme weather events include:

• Wind: after an intense windstorm which saw northern fulmars leave their nests at Cape Vera, glaucous gulls plucked about 40 per cent of the eggs on one nesting ledge before the parents could return;

• Fog: Arctic fulmars with broken wings were found scattered on the sea ice or beach below the cliffs following nights of thick fog at the Cape Vera and Cape Searle colonies after the birds apparently rammed into the rocky walls or each other;

• Wind: at Coburg Island, whose seabird colony lies near a large glacier, winds with gusts of more than 120 km/h struck birds as they took off from the breeding cliffs, and they were driven into the sea so hard that they were killed on impact with the water;

• Ice: moving sea ice near a breeding colony of murres trapped adults and crushed them. Abnormal ice conditions and strong currents also seem more likely to kill birds migrating or over-wintering in polynyas;

• Erosion: about 800 murres died on Prince Leopold Island in 2005, when an entire cliff face fell apart due to erosion and crashed down, bombarding nesting birds and their chicks with bits of stone;

• Disease: seabirds aren’t prepared for new parasites and diseases, such as the recent outbreak of avian cholera in Coral Harbor;

• Bugs: unusually warm breeding seasons bring high mosquito populations, which can also cause stress and death;

• Snow: during heavy snowfalls, adult seabirds go out to get food, but their chicks gets buried in snow and dies;

• Rain: glaucous gulls on Prince Leopold Island died of exposure due to a heavy rain in August, which soaked through their feathers. “High Arctic birds aren’t very well adapted to that,” Mallory said.

If the number of intense, freezing rain episodes or snowstorms increase in the Arctic, the CWS says the Arctic can expect higher levels of avalanches, nest abandonment, and predation.

And if warming temperatures lead to longer, hotter summers, less sea ice cover and more frequent, intense storms, the “unusual” mortality of Arctic seabirds may increase as a result.

New marine threats to seabirds are likely to accompany warmer temperatures and reduced sea ice, such as ship-based tourism, ship transport, and industrial fisheries, the CWS predicts.

So, the ways seabirds die may also become more typical of southern latitudes, where fishing, hooks, nets, collapses of food, oil spills and diseases are the main killers.