Not just cuckoo's clock that's upset by climate change

Bats falling from trees. Cranes staying put. Whales losing weight. Global warming is causing havoc, writes FIONA McCANN

CUCKOOS, LONG the bane of birdlife due to their habit of offloading eggs in the nests of all and sundry, are getting their comeuppance. Turns out they’ve fallen behind the migratory birds whose nests they usually use: those guys are moving north earlier due to climate change and leaving the cuckoos without the surrogate parents they require for raising their young.
Cuckoos aren’t the only ones confused by climate change however. The following five species have been both baffled and battered by environmental alterations, and often to an extent that can seriously threaten their survival.

POLAR BEARS
These iconic bears are becoming the poster animals for climate change, given that increasing temperatures globally have been melting the Arctic ice shelf, and many are drowning in their quest for food.

The bears need sea ice on which to hunt seals, but longer ice-free periods mean longer time between meals, and researchers say many polar bears are finding they don’t have the required reserves to tough it out between feeds.

As if that wasn’t enough, the seals they normally feed on are also in shorter supply, given that the fish they in turn feed on are more scarce, and so on down the food chain. Put plainly, the shrinking polar ice cap means polar bears, who need ice to survive, are also shrinking in numbers. Some ecologists are warning that they could be gone entirely 100 years from now.

WHALES
Not only are whales in the wrong place at the wrong time these days, what with their usual foodstuffs thriving closer to the poles because of warmer oceans, but they’re losing weight. Though this might be considered good news for many of their human counterparts, it’s bad news for whales, who rely on blubber for insulation and energy. According to a Japanese research team, whales are getting thinner which indicates big changes in their ecosystem.

And this loss of weight, tough though it may be to believe, could in turn be affecting their ability to reproduce. The problem is that krill, a staple food for baleen whales, grows in sea ice, so warming oceans mean migratory whales such as the humpback and blue now have to travel about 600 miles farther south for food. Small wonder they’re slimming down, but the consequences could be fatal.

BATS
Losing blubber is one thing, but dropping dead is another entirely. Yet that’s just what happened to thousands of Australian bats when scorching heatwaves linked to climate change caused them to flap their wings in a bid to cool off.

This, sadly, had the opposite effect. On one particular day in 2002, temperatures soared to 42 degrees wiping out 6 per cent of the flying foxes in nine colonies in New South Wales.

As many as 50 per cent of young bats died in the heatwave, finding themselves ill-prepared for the scorching temperatures. What happened was that, as things got hotter, the hanging bats began to fan their wings to cool themselves, but within a couple of hours of this frenzied activity they started panting and drooling saliva.

Finally, according to reports, bats began falling from the trees and dying within minutes – literally dropping dead. Researchers have estimated that over 30,000 flying foxes in Australia have died due to heatwaves in the past 15 years.

TURTLES
Turtles have it bad. Particularly male turtles. Get this: with turtles, the sex of the offspring doesn’t come down to any of that X and Y chromosome business, but is determined by the incubation temperature of the eggs after they’ve been fertilized. In many turtle species, the
warm ones become female, and the cooler ones male. This has led some scientists to extrapolate that it’s potentially curtains for male turtles as the global temperature heats up.

And without the males, there’s not much hope for the rest. Even if a few brave soldiers make it, they’re facing a host of other climate change challenges, given that their digestion rate, growth and reproduction are all closely related to temperature, and these guys aren’t famed for their quick reactions. Adapting to rapid changes may take a bit longer for slow-moving turtles, and time could run out before that happens.

CRANES
Climate change has caused particular confusion for migratory birds, who are accustomed to upping sticks when the weather changes. What happens when the weather doesn’t do what it used to is that many of them either migrate earlier, change their routes, or in some cases, settle down and giving up on the whole migration thing altogether.

One example of the latter is the crane, a bird that normally leaves the cool climes of Germany in the winter to wait it out in the balmier resorts in Spain and Portugal.

But rising temperatures have apparently fooled the cranes into thinking that it’s okay to stay put after all. Having ditched their travel plans however, many of the birds subsequently suffer when temperatures in Germany dip so low that they cannot survive the harsh winters.

http://www.irishtimes.com/newspaper/weekend/2009/0627/1224249639966.html