Seabird sites in southern Africa
Geyser Island
Les Underhill
Animal Demography Unit
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Photo B.M. Dyer
Geyser Island from the air. "Shark Alley" is on the left
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This tiny 3-ha island is separated from Dyer Island
by a narrow channel. The island is rocky, with no vegetation at all.
This island supports one of the largest Cape Fur Seal Arctocephalus pusillus colonies
in the Western Cape, with an estimated 55 000 seals being based here
in 2000. The seal population has increased dramatically here in recent decades.
The seals attract Great White Sharks Charcharadon charcharius,
and the channel between the two islands is popularly known as "Shark Alley".
The best time for seeing the Great Whites in Shark Alley is during the winter
months.
In spite of all the seals, Geyser Island also has a few birds species
- see the species list below.
Competition with seals for space is a major problem for seabirds on
Dyer Island. A small population of African Penguins continues to find an area in which
to breed, but numbers have declined in the last decade.
At least one pair of African Black Oystercatchers breeds on the island.
During summer, a few Turnstones, migratory Palearctic waders which
breed in the Arctic, feed along the rocky
coastline. Bank Cormorants, a "Vulnerable" species,
breed on sites which are generally inaccesible to seals.
One such site is on top of a huge beam of wood,
the keel of a ship, Prince Port, which was wrecked on
the island in March 1885 - the keel can be seen in the second and
fifth pictures on the left. The Prince Port is one of eight
shipwrecks on this tiny island.
Geyser Island is a nature reserve of the Western Cape Nature Conservation
Board. It has no visitor access facilities. Wilfred Chivell (082 801 8014)
operates boat trips to Shark Alley to view the seals, and various operators
provide shark-viewing opportunities, including cage-diving.
Landing on Geyser Island is hazardous, requiring a carefully-timed
leap onto mussel and barnacle encrusted rocks, in between wave surges.
Once on the island, one needs to steer clear of the seals, which panic readily.
Bird List for Geyser Island
Compiled by Bruce Dyer,
Marine and Coastal Management, Department of Environmental Affairs and
Tourism
This bird list is based on historic records and on
irregular official visits to Geyser Island made during
the period 1987-2000. It includes species seen on the island,
and at sea in the immediate vicinity
- African Penguin
- Southern Giant Petrel
- Northern Giant Petrel
- Cape Gannet
- Whitebreasted Cormorant
- Cape Cormorant
- Bank Cormorant
- Crowned Cormorant
- African Black Oystercatcher
- Turnstone
- American Sheathbill
- Kelp Gull
- Hartlaub's Gull
- Swift Tern
- Sandwich Tern
- Common Tern
- Antarctic Tern
- Cape Wagtail
Photo L.G. Underhill
Geyser Island from Shark Alley
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Photo L.G. Underhill
Cape Fur Seals on Geyser Island
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Photo B.M. Dyer
Geyser Island, October 1990. Cape Fur Seal co-existing with African Penguin and
Whitebreasted Cormorant - this kind of scene no longer occurs
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Photo L.G. Underhill
Bank Cormorants nest on the keel of the Prince Port on Geyser Island. This vessel was wrecked here in March 1885
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Photo B.M. Dyer
This Geyser Island African Penguin has built its nest out of seal fur!
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Photo B.M. Dyer
Geyser Island, taken from Dyer Island, with Shark Alley in between them
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