Avian Demography Unit Department of Statistical Sciences University of Cape Town

While working as coordinator of a UN-financed artisanal (local, small-scale) fisheries project in Angoche, on the northern Mozambican coast, I spent some of my spare time making observations for the Mozambique Bird Atlas Project. During this time I 'discovered' a breeding colony of Sooty Tern Sterna fuscata on a tiny coral island, Puga-puga, in the Segundas Archipelago.

   Puga-puga (16°26.50’S, 39°56.60’E) is an island of 300 x 150 m, surrounded by a coral reef and a lagoon of a couple of square kilometres. Vegetation is scarce with only grass and Ipomea brasiliensis. There is no fresh water on the island. I made several visits to the colony between August and October 1997, which gave me a chance to follow all the phases of breeding.

   The birds started to arrive in July. I went there for the first time on 4 August. I estimated the number of birds on the island to be 12 000-13 000, but there was a significant number flying around. At that time local fishermen were intensively exploiting the colony, killing the adults by hitting them with sticks and collecting the eggs. They walked through the colony every two hours or so and collected all the freshly laid eggs they could find. Both the birds and the eggs were taken to the market in Angoche to be sold. That day I counted 300 eggs stored in a hole in the beach before being sent to the continent in a sailing canoe. The shells of freshly killed turtles (Green and Loggerhead) are often used as convenient transport devices.

   During my second visit on 17 August, the number of birds was significantly less, not more than 8000. I counted 410 pairs of wings on the ground; the carcasses are sold without wings. There were still some fishermen collecting eggs. We decided to support the local Marine Administration team logistically and financially so that they could enforce the prohibition of this activity by having some of their agents present on the island during the nesting period.

   On 30 August, the number of birds was approximately the same. I saw the first chicks on 14 September, although the guards informed me that they had seen the first hatchling the week before.

   On my last visit of 17 October, I counted 1300-1400 chicks, plus 300-350 eggs. The birds started to leave the island in November and were all gone by the end of December. The only other bird species observed on the island was the Swift Tern S. bergii, with a maximum of 380 birds in late August, but I did not find any nests.

   According to the local fishermen, Puga-puga is known as a breeding island for terns every year between July and October. It seems that the only other island in the area to host nesting seabirds is Coroa, in the Primeiras Archipelago, located further south, but I did not have a chance to go there. The Coroa colony remains protected by traditional beliefs; it is believed that whoever kills a bird or collects eggs will be caught in a storm during their trip back to the continent. Such beliefs apparently also protected the Puga-puga colony in the past.

   The Sooty Tern is an interesting pelagic bird, spending years at sea before coming back to land to breed. Roberts' Birds of Southern Africa (Maclean 1995), which includes southern and central Mozambique, states that it is an 'uncommon vagrant' in southern Africa and that breeding is ‘extralimital’. In The Atlas of Southern African Birds, the species is said to be regular off Mozambique, sometimes in large flocks (Ryan 1997). Little is known about bird distribution in northern Mozambique, an area not yet covered by any published field guide. This is the first known breeding colony of Sooty Tern in Mozambique and although breeding is known to be opportunistic for this species, Puga-puga appears to be a regular breeding site.

   It seems that there has been strong human pressure on the nesting population in recent years. Our protection attempt was improvised and is probably not sustainable in the future. Both the Primeiras and Segundas archipelagos are still characterized by high marine biodiversity, rich coral reefs with little human impact, and an important population of turtles. Considering the isolation of the islands and the lack of resources of the Mozambican central administration to enforce regulations, the most realistic way to maintain the biological richness of these islands would be through sustainable use of resources like the Puga-puga Sooty Tern colony. The harvesting of some of the eggs would probably have limited impact if the killing of adult birds were stopped. Intensive work with local communities is needed as a first step and should be started as soon as possible by NGOs or other donor-financed organizations.