134 | Chapter 7
island that, from afar, looks white. Only when nearing the island does
one realise that the white coating is not an accumulation of droppings
but a noisy living carpet of tens of thousands of adult gannets. But the
study birds did not simply carry GPS loggers, seven also bore time-
depth recorders. Thus Patrick’s team could identify when and where, on
their foraging trips, the gannets were diving. Couple this information
with high- resolution data on the location of commercial fishing vessels,
now available for vessels greater than 15 m fishing in UK waters (regard-
less of nationality), and it was possible to discover whether every gan-
net dive was close to a vessel or not. With around 200 dives available for
each gannet, it transpired there were two birds that nearly always* dived
near a fishing vessel, three that showed flexibility, and two that never
dived near a vessel. However there was no sign that foraging effort, mea-
sured for example by trip duration, differed between scavengers and
non- scavengers. Nor was there a difference in the body con dition of the
birds. It looked as if the two habits delivered equivalent benefits, a point
to which we shall return.
Such consistent patterns are not the sole preserve of flying seabirds.
At least some penguins follow suit. King Penguins in the Falklands, feed-
ing large chicks during the southern winter, consistently head north.^4
Their trips, reaching a distance of about 300 km from the study colony
at Volunteer Point, mostly target the margin of the Patagonian Shelf
where the shallow shelf (water about 200 m deep) begins to slope down-
ward to the 5,000 m abyss of the South Atlantic. But, as often with
scientific studies, it is right to strike a cautionary note. The northward
outward journey meant the penguins benefitted from the north- flowing
Falklands Current. Perhaps the consistent penguins all had the wit to
recognize and utilise a watery helping hand.
Modern tracking has frequently identified repeated use of particular
areas by individual breeding birds. That opens the possibility that mi-
gratory routes of individual birds might be consistent and consistently
different from those of their fellows. That is certainly true of Wandering
Albatrosses on the French Iles Crozet and Kerguelen in the Southern
Ocean. Wonderful studies have tracked adult albatrosses in the interval
- (^) At least 80 percent of dives were near a vessel.