|How we did this Study|
|Waved albatrosses nest mostly in the
Galápagos Islands, an island group 1000 km (600 miles) off the South American coast in
the Pacific Ocean. Just a few pairs have their nests on an island called Isla de La Plata
off the coast of Ecuador in South America. All of the rest, over 99% of the birds, nest on
Isla Española in the southeast corner of the Galápagos.
In 1995 we used satellite tracking to test two hypotheses about the movements of parent albatrosses during feeding trips. During the nesting season, people passing through the eastern Pacific on boats have reported seeing flying waved albatrosses mostly in two areas. One is within the Galápagos, within 200 km of Isla Española and especially in the western part of the island group. The other area is near the South American coast, off Peru, 1500 km (about 1000 miles) to the southeast of the Galápagos. This is quite a big difference! Certainly it would take a parent bird a lot longer to fly all the way to the Peruvian coast that it would to the western part of the Galápagos, so it was reasonable to expect our parent birds to look for fish and squid prey in Galápagos, near their nests. So, our two hypotheses were:
1. parents looking for food stay
within the Galápagos
We used satellite tracking to test these hypotheses. The data from the satellites could show that:
1. neither of these hypotheses was correct, if the birds travelled to some other location than Galápagos or the Peruvian coast, or
2. that only one was correct, or
3. that both were correct.
From a scientific point of view, the hypotheses were falsifiable. They could be falsified, or in other words shown to be incorrect. Scientists accumulate new information about nature by suggesting hypotheses and then turning around and trying to prove the hypotheses wrong. If they try to prove it wrong and cannot, then they have some confidence in the hypothesis. Both of the hypotheses that we suggested were falsifiable (they could have been proven wrong by the satellite data).
In April, 1995 we attached a satellite transmitter to each of five birds on Isla Española. We chose three pairs of birds on the day that the mother laid their single egg of the year. We captured the male and female in two pairs, and just the female in the third pair. This is not too hard with albatrosses because they allow people to get close to them, especially when they have an egg to guard. With the bird in hand, we used a quick-setting glue to fasten the transmitter to the feathers on the back of each bird, and then we put the bird back at its nest. The transmitter backpack weighed about 85 g, and added 1-3% to the bird's mass (weight). The backpack was nestled under some feathers, so that the bird was still streamlined even though we had added a bump to its figure.
We then kept track of when each tagged bird was at its nest and when it was away. When the bird was at its nest we knew its exact location, and we could compare that location with the location reported by the satellites. This was a way to "Check the Satellites' Accuracy", another part of this web site. We tracked these birds for up to 8 weeks, depending on the bird, into June, 1995.