Three of the birds stayed close to the island as expected, despite the poor prospects for fishing. The other two set off independently down the coast, halting 160 and 190 km from the island. One of these birds ended up travelling a remarkable 895 km from the colony before its signal was lost. The penguins moved in the direction of waters that satellite maps revealed as being cooler and richer in microscopic plant life - just the sort of area that would attract shoals of anchovies and sardines. The transmitters themselves may have confused things.
Penguins produce as much disturbance or 'drag' in the water as a coin.
The tagged birds may have been hauling around the equivalent of another penguin. This alone may have made hunting tough enough to inspire the penguins' dash south to richer waters. Ancel, A. et al. Foraging behavior of emperor penguins as a resource detector in winter and summer. Nature 360, 336-339.