Tracking Ocean Wanders (PDF, 5 MB) - BirdLife International

in depth with occasional trips into deeper waters
associated with the shelf edge. (Brothers et al. 1998, Hedd
et al. 2001)
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Tracking ocean wanderers: the global distribution of albatrosses and petrels – Results
Aleks Terauds and Rosemary Gales
3.2 SYNTHESIS OF DISTRIBUTION OF
BREEDING BIRDS FROM DIFFERENT
POPULATIONS OF SELECTED SPECIES
Black-browed Albatross Thalassarche melanophrys
The utilisation distribution map (Figure 3.18) illustrates
the largely mutually-exclusive foraging ranges of breeding
Black-browed Albatrosses from different populations. This
was particularly apparent for the South Atlantic/South
American region, where data coverage represented all
populations and most breeding stages. Although birds
from both South Georgia and Chile foraged in many cases
at very large distances from nest sites (hence the greater
overall ranges), there was little or no spatial overlap
between the two populations, or with birds from the
Falkland Islands (Malvinas). The same applies in the New
Zealand sector where satellite-tracking of the closely-related
Campbell Albatross Thalassarche impavida (Waugh et al.
1999) indicates only marginal overlap with Black-browed
Albatrosses tracked from Macquarie Island, despite their
relative geographical proximity.
Although not indicated on these maps, the distribution
of Black-browed Albatrosses during winter, as determined
through GLS tracking (BAS unpublished data: see also
Section 3.3.3, Figs. 3.27, 3.28 and 3.29), also shows that
most foraging areas are exclusive to birds from a particular
island group. However, there is rather more overlap than
during the breeding season, with, for example, movements
to the Chilean shelf by Black-browed Albatrosses from the
Falkland Islands (Malvinas), and to northern New Zealand
waters by birds from Diego Ramirez.
In terms of habitat preferences, more than half the
breeding birds tracked from each site visited shelf or shelfbreak
waters, in many cases relatively close to their colony.
Indeed, Black-browed Albatrosses from the Falkland
Islands (Malvinas) were confined almost exclusively to the
Patagonian Shelf, either very close to breeding sites or in
several discrete areas to the north, including one inshore
area close to Argentinean fishing ports (Huin 2002 and see
Section 3.1.1). Similarly, birds tracked from Kerguelen
mostly travelled to the northern and eastern Kerguelen shelf
and to the north-east of Heard Island (Weimerskirch et al.
1997c). By comparison, although many Black-browed
Albatrosses from South Georgia also foraged in shelf and
shelf-slope areas (around and to the north-west of South
Georgia, and at the South Orkney and South Shetland
Islands), many others visited Antarctic Polar Frontal Zone
(APFZ) waters to the north, and deep, oceanic waters to the
south (Prince et al. 1998). Similarly, although Campbell
Albatrosses spent more than 50% of the time in adjacent
Figure 3.18. Overlap of utilisation distributions for breeding Black-browed Albatrosses tracked from five different populations. Chile (Isla
Diego de Almagro, Islas Ildefonso: incubation, Islas Diego Ramirez: incubation, brood and post guard) (n=30,863 hrs); Falkland Islands/Malvinas
Beauchêne and Saunders Islands: incubation and post guard) (n=13,396 hrs); South Georgia (Bird Island: incubation and chick rearing) (n=7,718 hrs);
Iles Kerguelen (incubation and chick rearing) (n=7,678 hrs); Macquarie Island (incubation and brood guard) (n=3,956 hrs). Where possible, density
distributions were weighted by the proportion of time spent in each breeding stage and the proportion of breeders at sea during the breeding stage, as
well as by the colony size. (Unable to determine number of individuals from all datasets, so sample sizes are only given in number of hours tracked.)