adUlt migrations | 69petrels. It nests in the wet dense forest of the west coast of New Zea-
land’s South Island. Once breeding concludes in November, the petrels
head east across the Pacific to similar latitudes off Chile and, in the
Atlantic, over the Patagonian shelf off Argentina. The 7,000 km journey
averages 6 days, and the return in April is barely slower, 10 days. During
these journeys, Todd Landers found petrels spent, respectively, a mere
10 and 17 percent of their time on the water.^19
In general these mammoth seabird treks appear to be undertaken
without the prior fattening often observed among landbirds.* This is pre-
sumably aided by the fact that seabirds have the possibility of snacking
as they travel, if they encounter prey.
In fact, setting aside the species for which flying is impossible, namely
penguins,^20 † or enormously hard work, for example auks, the matter
could be viewed from an alternate perspective. We might expect the
overall speed of long- distance flying seabird journeys to exceed 500 km/
day unless interrupted by significant stopovers. Just such stopovers
were discovered for the Greenland Arctic Terns mentioned earlier in
the chapter, and they have emerged in other studies. Indeed the regu-
larity with which migrating seabirds undertake mid- ocean pit- stops
has surprised the research community, especially as the areas used for
such stops are evidently favourable and repeatedly utilised. However
the areas used vary between different species with different diets and
feeding styles.
After breeding in Alaska, Arctic Terns, studied by a group led from
the US Fish and Wildlife Service, migrated through the eastern Pa-
cific.^21 Southbound, they utilised a succession of stopover sites, almost
as if the road trip had been planned in advance and the motels booked,
each chosen for its capacity to provide copious food. The first staging
point was off Oregon and northern California where birds lingered for
- (^) The fat Alaskan Bar- tailed Godwits destined for New Zealand were mentioned earlier in the
chapter. Many small perching birds also double their body mass before embarking on a major
migration, for example a Saharan crossing. Exceptions include the swallows and similar species
that can potentially feed on flying insects during their travels.
† (^) The daily travel distance of juvenile King Penguins of 45 km was mentioned in Chapter 2. It
is on a par with the 23 km/day achieved by Magellanic Penguins migrating north along the east
coast of Argentina.