USA birds: Probably someone let off a huge banger-rocket near the flock and they ALL died of shock at the same time. Or they were part of a huuuuge flock (they were starlings after all) passing over which had a very virulent and fatal disease passing through it, causing multiple birds to just fall out of the stream as they finally gave up. 1% of 200,000 is already a cool 2000 but isn't exactly an epidemic.
That or it's just the most enormous, rather sick hoax ever.
UK crabs: It's been unbelievably cold here in the run up to and just after christmas - I experienced double digit negative celcius temperatures in the midlands for the first time ever for a start, and it persisted for a good 48 hours as part of a much longer spell of bitterly cold and snowy weather. You may have heard about it - e.g. Heathrow closing, which is basically unprecedented. At least, not since we escaped the mini ice age of the 60s, where air travel was less important, no-one gave a crap about animals or ecology, the air was full of smoke and the sea full of radioactive sewage.
What happens on land is mirrored, although to a much milder extent, in the water. However, when it's already maybe 4 celcius out there, tops, and you're living on a knife edge, 1 or 2 degrees colder could be enough to shock you to death, and particularly the shallower inshore waters may have been only around 0 (saltwater freezing at a lower temperature of course). Hence crabs end up dying of thermal shock, or maybe they surfaced and got hit with a triple whammy of extra cold water, extreme cold on land, and a horrible evaporative windchill. Mmm, flash-frozen crab!
Sweden, who knows. Who cares. I've got my Ikea purchase for the year, I'm immune.
