| Lost a Pound,
Found a Penny
by Dr Mike Bingham
There seems to be a lot of confusion as
to whether penguins have declined or increased in the Falklands.
The answer is both. Whether you concentrate on the decline, the
increase, or the overall change depends on your viewpoint or political
As the British Task Force set sail in 1982,
newspapers described the Falklands as an island of two thousand
people and six million penguins. This penguin estimate was not far
out. Two years later an assessment of seabirds in the Falkland Islands
recorded 2,500,000 pairs of Rockhoppers and over 100,000 pairs of
Gentoo penguin (Croxall, J.P., McInnes, S.J. & Prince P.A. 1984:
The status and conservation of seabirds at the Falkland Islands)
Sadly Falklands penguins now number only
a quarter of that figure, despite recent increases by Gentoo and
Rockhopper penguins. These two species declined throughout the 1980s
and early 1990s, and reached their lowest point in 1995, since when
populations have recovered slightly.
Whilst it is comforting that Rockhoppers
and Gentoos have recovered slightly over the last 5 years, it must
be remembered that Rockhoppers still number less than 20% of just
18 years ago. This massive decline is documented in various scientific
publications by Ian Strange, Peter Prince and Dr Ian Keymer, not
just myself. These declines did not occur anywhere else in their
breeding range. The problem was unique to the Falklands.
This massive decline followed by slight
recovery is like loosing £1 on the horses and winning 5 pence. Like
a husband trying to justify his gambling, some people prefer to
talk about winning 5 pence, without acknowledging the overall loss
The good news is that Falklands Rockhoppers
and Gentoos do appear to have reached a new equilibrium that is
now in balance with current food availability. Provided that commercial
fishing continues to be carefully managed, these populations should
remain safe, albeit at a lower level than prior to commercial fishing.
The bad news is that Magellanic penguins are still declining.
It is impossible to give an accurate total
for Magellanic penguins in the Falklands, but we do know that study
sites monitored throughout the Falklands during the 1990s have shown
a 70% decline over the last 10 years, a decline which is still occurring.
It has been suggested that these declines
are part of a global trend, but that is not the case. Magellanic
and Southern Rockhopper penguins are only found in the Falklands
and South America, and there are no signs of decline in Chile or
Tierra del Fuego. Indeed the closest colonies to the Falklands on
Isla Magdalena (Chile) and Staten Island (Argentina) appear to have
increased as Falklands populations declined.
In order to better understand the reasons
for the Falklands decline, I began comparing Magellanic penguin
colonies in the Falklands and southern Chile 4 years ago. Funded
by the Conservation & Research Foundation in the U.S.A., the
project has already revealed some remarkable results. Over the last
4 years, breeding success and chick survival rates have been substantially
higher in Chile (average 1.35 chicks per nest) than in the Falklands
(average 0.82 chicks per nest).
This huge difference in breeding success
could well account for the gradual decline in Falklands population.
It suggests that insufficient chicks are being reared in the Falklands
to replace natural adult mortality. But why such a difference?
Around Isla Magdalena in Chile, where commercial
fishing is banned to protect wildlife, adult penguins require an
average of 18 hours to find sufficient food to feed their chicks.
In the Falklands the average is about 35 hours. If chicks in the
Falklands are only getting fed half as much food, it is reasonable
to suppose that fewer chicks will survive, which is what we see.
On Isla Magdalena just 24% of breeding adults
failed to raise at least one chick. In the Falklands however, this
was an incredible 63%. Almost two-thirds of all nests in the Falklands
completely failed. Of those that remain, only 21% raised two chicks
in the Falklands, compared to 45% on Magdalena.
It is important to remember that Isla Magdalena
is just 600km to the west of the Falklands, with almost identical
climate and weather. Indeed much of our own weather comes from this
Isla Magdalena was hit by wet weather this
summer, as was the Falklands, and chick survival was down at both
locations. The difference was that low chick survival on Isla Magdalena
(1.16 chicks per nest) is still higher than what the Falklands achieves
in a good year, whilst this year chick survival in the Falklands
plummeted to a dismal 0.58 chicks per nest.
Diet sample analysis shows that competition
still exists between penguins and the Falkland Islands' fishing
industry, especially for Magellanic penguins. This competition occurs
mainly for loligo squid (Loligo gahi) and blue whiting (Micromesistius
australis). Even using Falklands Conservation's own published
data (Clausen A (2000) Falkland Islands Seabird Monitoring Programme
Report, Falklands Conservation Report SMP8), Magellanic penguins
compete with commercial fishing for over one third of their observed
diet. This would explain the need to spend longer finding food for
chicks, with the consequential reduction in chick survival.
It is also important to remember that the
observed level of competition with commercial fisheries will be
an under-estimate. If there was no fishing activity the abundance
of loligo squid and blue whiting would be higher. Since diet sample
studies have only ever been conducted under conditions of reduced
abundance due to commercial fishing, measurements of competition
between penguins and the fishing industry will inevitably be under-estimated.
The link between penguin declines and commercial
fishing is further supported by similar declines in Falklands seals
and sealions. There are a total of seven species of penguin, seal
and sealion with breeding colonies in the Falklands. Five of these
compete with commercial fishing, and all these five species have
undergone major declines in the Falklands since commercial fishing
began. These species have not declined in the remainder of their
global breeding range, only in the Falklands. The two Falklands
species which do not compete for food with commercial fishing have
both increased since commercial fishing began, possibly filling
part of the niche left by species that have declined. The evidence
for a link between these declines and commercial fishing is almost
In the Falklands, Magellanic penguin populations
have declined so much that it is obvious from the colonies themselves.
Next time you visit a Magellanic penguin colony, look how many of
the burrows are actually occupied. At most Falklands sites 80 to
90% of burrows are unoccupied or derelict. A Magellanic penguin
in the Falklands has no problem finding a burrow. There are plenty
of ready made ones whose owners have either died or moved elsewhere.
On Isla Magdalena, virtual every inch of
the island is used by penguins. Even areas where the ground is unsuitable
for making burrows are used, with Magellanic penguins nesting on
the surface like Gentoos. Anybody who doubts for a moment that Magellanic
penguins have crashed in the Falklands should visit Chile to see
what a healthy colony looks like.
It can only be hoped that Magellanic penguin
populations will eventually bottom out, as they have for Gentoos
and Rockhoppers. If not, it could be that for future Falkland Islanders,
Chile will be the nearest place to see a Magellanic penguin.
(This article is a summary of my research
thesis. CLICK HERE to view full report)