July–August 2015 39kilometres in search of food. In
contrast, breeding shy albatrosses
don’t stray much more than 200km
on their foraging trips and stay away
for no longer than about 10 days.
“They keep to the Bass Strait
region and return to the colony all
year,” Rachael says. “One reason for
that may be that the Bass Strait
environment is productive and
predictable enough year-round to
allow the birds to stay.”
Shy albatrosses are long-lived and
slow to reproduce. They live for about
35 years, are in their prime between 10
and 25, and generally form lifelong,
monogamous pairs. A female lays a
single egg in September and she and
her mate take turns to incubate it over
10 weeks, one sitting on the nest while
the other is away foraging. The chick
hatches in December, fledges in
March and departs in April.
“Of the eggs laid in a given year,
fewer than half become a chick that
makes it to the end of the breeding
season,” Rachael says. “And we know
from our research that fewer than half
the chicks that survive to leave the
island make it back again.”
How Rachael establishes these facts
is down to the strategies she uses in her
program. One is to count breeding
pairs and chicks every year, yielding a
measure of breeding success. Another,
termed ‘capture, mark, recapture’,
involves fitting leg bands to chicks
before they leave the nest and readingthe bands of returning birds. Rachael
and her coworkers also fit GPS trackers
to birds to trace their journeys.
All the data from the program are
pieces of a gigantic jigsaw puzzle that
will one day yield a coherent picture.
Some trends are already emerging;
breeding success, for instance – the
survival rates of juvenile birds and the
number of breeding birds have begun
to decline in the past 10 years. Why
this is happening is still a mystery. It
may be linked to the numbers of
albatrosses killed as fishing bycatch or
to climate change and associated
changes in the ocean and the weather.
“With this project we’re trying to
understand the cumulative impacts of
all of the threats the birds face as
much as follow single lines of inquiry,”
Rachael says. “The cumulative impacts
can be quite massive.” AGOn the mark. An adult shy albatross has a
wingspan of up to about 2.5m. Rachael, above,
at left, Julie McInnes and Kris Carlyon check for
moulting feathers. At night the scientists camp
out in one of the island’s caves.圀漀爀氀搀䴀愀最猀⸀渀攀琀圀漀爀氀搀䴀愀最猀⸀渀攀琀
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