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South Africa

Bird Island, Lamberts Bay

Vincent Ward1 and Les Underhill2
1Cape Nature; 2Animal Demography Unit

 
The gannet hide on Bird Island
Photo Les Underhill
The gannet hide on Bird Island
   
 
View of the gannet colony from upstairs in the hide
Photo Les Underhill
View of the gannet colony from upstairs in the hide

Bird Island at Lamberts Bay is the northernmost of the seabird islands on the west coast of South Africa. Apart from some small cormorant colonies on rock stacks, there are no large seabird breeding colonies north of Lamberts Bay until the Namibian islands are reached. This is a gap of about 600 km.

The island is small (2.2 ha). It is only about 60 m offshore, and is connected to the mainland by a causeway, built in 1959, which helps create the the storm shelter for the small harbour at Lamberts Bay. The causeway makes it easy for visitors to get on and off the island, but also makes the seabirds on the island vulnerable to predators such as dogs, cats, rats and mongooses.

Apart from Robben Island, Bird Island is the only island along the South African coastline that is geared up to receive tourists. Robben Island is massively altered, so Bird Island is the only accessibly place for an "authentic" guano-island experience. On Bird Island, the tourist facilities consist of a hide, built in 1998, on the edge of the gannet colony, a small museum which portrays the history of the guano industry and a restaurant. The museum was constructed within the former guano labourers' quarters on the island.

The new bird hide is a love-it or hate-it feature. It is a two-level concrete structure, clad with fibreglass "rock". The pattern and colour of the artificial rock were carefully constructed to match the natural rock on the island, and the hide is probably one of the most architecturally important bird hides in the world. It provides extraordinarily good views of the Cape Gannet colony. From the lower level, the gannets go about their daily business within a few metres of a huge window of one-way glass. Upstairs is an open viewing platform which provides an overview of the colony, and where the cacophony of calling gannets is overwhelming. The gannets breeding in spring and summer.

Cape Gannet arriving at the colony from a feeding trip
Photo Les Underhill
Cape Gannet arriving at the colony from a feeding trip
 

The gannet colony is the main attraction at Bird Island, Lamberts Bay. Of the six Cape Gannet colonies, this is the only one where the birds can readily be viewed. The other colonies are at Mercury Island, Ichaboe Island and Possession Island in Namibia, and in South Africa at Malgas Island and at the other Bird Island, Mandela Bay, which is near Port Elizabeth in the Eastern Cape. There has not always been a gannet colony in Lamberts Bay. This colony is believed to have formed in 1912. The process whereby new Cape Gannet colonies form is unknown, because young gannets are incredibly faithful at returning to their natal islands when they mature and start breeding, and movements between colonies are exceptional.

The numbers of breeding gannets on the island has fluctuated over the decades, in part a consequence of the way in which the guano was scraped. If two much guano was removed, the breeding area became basin-shaped and flooded after rain. During the 1940s, about 300 tons of guano was harvested annually, but this dropped to about 150 tons in the 1960s. The area of the island underneath the gannet colony was paved with cobblestones to facilitate guano collection. Guano is no longer removed from any of the South African offshore islands; as a result of the availability of articifial fertilizers, guano harvesting on the offshore islands is no longer commercially viable. The Bird Island gannets were in decline between 1956 and 1967, but the population has recovered, and currently between 4000 and 6000 pairs breed annually.

  Cape Cormorant colony
Photo Les Underhill
Looking across the Cape Cormorant colony to the factories on the other side of the harbour. Hartlaub's Gulls breed on the anchored fishing vessels

Originally, Bird Island in Lamberts Bay was predominantly an African Penguin breeding colony. This population has dwindled to about 50 breeding pairs, and is at risk of going extinct.

Cape Cormorants breed on the island in variable numbers, depending on offshore food availability. The number of breeding pairs varies from almost nothing to a maximum count of 13 000 each year. In 2001, about 3000 pairs bred. There are also small colonies of Whitebreasted Cormorants and Crowned Cormorants in most years. The Crowned Cormorants also breed on the masts of old fishing boats anchored in the harbour. Before major extensions were done to the harbour in the 1970s, there was a significant breeding population of Bank Cormorants. This "Vulnerable" species no longer breeds on this island.

The number of pairs of breeding Kelp Gulls has increased steadily over recent years. In spring 2001, there were about 250 pairs. This is one of the Kelp Gull colonies intensively monitored by scientists from Marine and Coastal Management, and visitors should look out for (and report to SAFRING, any birds they see with engraved colour rings like the one in the picture. The information needed is time/date, place, the two-letter engraving on the colour ring, and the colour of the ring. The reports can be emailed to safring@gmain-com.

Hartlaub's Gulls regularly breed on the fishing boats in the harbour, many of which are moored at anchor for months at a time. Swift Terns sometimes breed on the island. These two species, plus the Kelp Gull, are the major components of the gull and tern roost on the island. Common Terns and Sandwich Terns also join the roost, with largest numbers in summer. Greyheaded Gulls are also usually visible. Vagrants pitch up in this roost; for example, in October 2001 a Franklin's Gull was present for a few days.

As on most islands, the breeding birds face a variety of threats. Predators crossing to the island over the causeway represent an ongoing threat to the birds. A population of Cape Fur Seals has recently formed, and become a breeding site. Small numbers of young male fur seals develop skills at attacking and killing seabirds, especially cormorants, penguins and gannets; even though the number of seals engaged in this activity is small, they can make a substantial impact on seabird breeding populations. The threat of an oil spill is ever-present, but unpredictable. Both the Cape Gannet and the African Penguin are in competition with the fishing industry for Sardine and Anchovy; a suggestion to create a marine reserve around the island, with a diameter of 25 km, in which commercial fishing is either banned or limited should be investigated. Guano scraping has been discontinued, but human disturbance remains a threat; this can be minimized provided visitors stick to the paths on the island.

Bird Island is managed by the Western Cape Nature Conservation Board.

Kelp Gull
Photo Les Underhill
Kelp Gulls breed on the island in spring and early summer
 
Two Greyheaded Gulls and two Hartlaub's Gulls
Photo Les Underhill
Two Greyheaded Gulls and two Hartlaub's Gulls