| When high-powered seabirds like albatrosses go to sea,
they could easily fly far enough to meet up at sea with strangers
from the same species but from different islands. Good places to feed might have
birds from more than one, even many different, islands. For example, a relative of
albatrosses called the dark-rumped petrel has colonies in the Galapagos Islands and in the
Hawaiian Islands, and these are separated by 5,000 km of island-less ocean. Still,
members of these two populations sometimes feed in the same places between the two island
groups. If a ship-based biologist recorded these petrels in water near Hawaii and
distant from Galapagos, if would be hard to know which islands those birds called
home. Same problem applies to the albatrosses. We want to know where Hawaiian
birds go to feed, but just seeing Laysan and black-footed albatrosses at sea and recording
the locations is not good enough. The reason is that both of these species nest in
other places in the Pacific Ocean, and birds from those islands may be mixing with our
Hawaiian bird |
