I found this while looking for a penguin gif:
On November 2nd timothy of Slashdot asked if penguins topple when planes fly over? The British Antarctic Survey has organized a the first expedition to explore this theory and came back with news now.
The short answer: No, penguins don't fall over.
In November the BBC released a story covering a research project that took UK scientists to the South Atlantic. They wanted to discover if there is any truth in the tale that many aircraft pilots told the public.
Pilots often reported that when they were flying over a colony of penguins the birds were watching the planes, but instead of moving their bodies to follow the aircrafts they only moved their heads which lead them fall backwards over. This was said to happen to the entire colony of penguins and not just to some individuals.
If this was true, it could lead to a serious problem. Penguins only live in colonies around the antarctic and there aren't that many. If the aircrafts disturb their breeding pattern future of penguins is uncertain. The research project was acknowledged by fears that breeding patterns of the birds may be disturbed and interupted by aircraft activity such as jets and helicopters from aircraft carriers.
From the beginning of this research project there was no evidence that penguins actually fall over. All the scientists knew about were myths of aircraft pilots who supposedly watched entire colonies topple.
The researchers from the British Antarctic Survey went to South Georgia, an island belonging to the Falklands, in order to observe a colony of King Penguins. With help of the Navy and their ice patrol vessel HMS Endurance the scientists let helicopters fly over the colony of penguins and watched the birds.
The results were different from what pilots formerly reported. The birds did not fall backwards over or watched the helicopters. Instead the penguins went quiet and some moved away from the disturbing noise. Though, after the helicopters were gone the penguins moved back to their regular places. Please read the entire report.Frankly, I can't believe they really went to check!!! LOL
more info here.