78 | Chapter 4
While activity patterns indicate and sometimes pinpoint where and
when moult occurs, the most dramatic signal would come from species
that lose the power of flight altogether during moult. This is what larger
auks do, but they routinely spend most of their non- breeding lives on
or under the water so the change in daily routine is not very marked.
Ecologically equivalent to the auks are the diving petrels of the South-
ern Hemisphere. The diving petrels tracked by Matt Rayner to the Ant-
arctic Polar Front spend up to 95 percent of the 24 hours on the water
in the middle of their non- breeding period, and are probably nearly
flightless.
Rightly renowned as masters of flight, albatrosses replace their prin-
cipal wing feathers, the primaries, in a complex sequence. Sometimes
spread over two years, the process has been interpreted as an adaptation
to ensure albatrosses maintain that magisterial status, and never be-
come floating and flightless, unable to feed. This interpretation prob-
ably stands for the higher latitude species of the Southern Hemisphere
but it falters for lower latitude species. Step forward the Laysan and
Black- footed Albatrosses that despatch their chicks from Midway, at
the north- western end of the Hawaiian chain, in June or early July. The
breeding adults then head into the North Pacific and concentrate off
Kamchatka in the case of the Laysans, or slightly further south off Japan
and in an alternate area around the Aleutians in the case of the Black-
footed Albatrosses. Following this northward journey, between 30 and
70 days after quitting the colony, there is a period of some three weeks
when sustained flight bouts disappear from the birds’ daily routine. All
birds of both species spent at least one full day during this time entirely
floating on the water.^35 Further, Laysan Albatrosses on average spent
seven days floating on the water’s surface for more than 90 percent of
the day and 16 days floating for more than 80 percent of the day. The
pattern for Black- footed Albatrosses was very similar. Clearly the birds
were virtually flightless, only foraging intermittently, a state from which
they ‘recovered’ in the ensuing months.
Today the scarcest North Pacific albatross is the Short- tailed. While
formerly the species was so abundant on the Japanese island of Tor-
ishima (Izu Islands) that a light railway was needed to transport feathers
from the killing fields, the nesting areas, to the beach prior to export,