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July 13, 2012By Justine Braby, Animal Demography Unit, University of Cape Town
The Damara Tern is a curious little creature. It breeds in one of the harshest places on earth, where the icy Benguela Current meets the endless sand that is the Namib Desert.
It lays one egg in a scrape in the ground amidst prowling jackals and circling kestrels and crows. Only a third of all chicks survive to fledgling.
Ringing tern's
The gravel plains amongst the barchan dunes along the coastline of central Namibia, between Walvis Bay and Swakopmund, hold the densest number of breeding Damara Tern pairs in the world. The area and timing of breeding unfortunately coincides with the Namibian summer vacation, when thousands of holidaymakers flock to the coast for fun times in the sea and sand. Off-road driving is a popular recreation during peak season, and quad-bikes and off-road vehicles are a common sight in the dunes. So not only do the Damara Tern parents have to worry about their offspring being eaten by jackals, crows, kestrels, gulls, rodents, and even beetles and chameleons, but also that their eggs or chicks may be trampled by quad-bikes, motocross bikes, off-road vehicles, horses and pedestrians strolling around in the dunes.
In the south, within the restricted diamond area of Namibia known as the Sperrgebiet, the Damara Tern nests on salt pans and gravel plains where ground temperatures can reach 50°C and winds move loose sand at speeds up to 80 km/hour. And although the areas are restricted, the possibility of diamond mining within each breeding area threatens the survival of the Damara Terns here too. So it seems that the fate of the Damara Tern as a species hangs by a thin thread. But it is not all hopeless. With the awareness of the vulnerability of a species comes a certain sympathy from the public. After years of monitoring the downward spiral of breeding success at the breeding colonies near Swakopmund, it was decided by conservation authorities to protect these colonies by building fences around the perimeter of the breeding terns and controlling the movement of quad-bike tour operators in and out of the areas. Since then people have been prohibited from entering these breeding areas.
As the ‘zonation’, if you will, of the dune belt between Swakopmund and Walvis Bay was open to public opinion (meetings were held to include all stakeholders), and the area that is restricted makes up less than 10% of the entire dune belt – which leaves 90% of dunes to play with – it comes as a surprise that there is still resentment towards prohibiting access to this small area. Since the fences have been erected, sporadic occurrences of people collapsing fences and rushing through breeding areas on quad-bikes, motocross bikes and off-road vehicles still exist and have accounted for direct losses in breeding attempts by the Damara Terns in the area. However, human disturbance in these areas has decreased drastically and Damara Tern breeding success has increased over the years as a result of the fences.
Deserves special attention and pride
Due to increased awareness of the Damara Tern, Namdeb Diamond Corporation (Pty) Ltd funded a two-year monitoring project on the possible impact of diamond mining on the breeding productivity of the Damara Tern within the Sperrgebiet, and Rio Tinto and BirdLife International funded a three-year monitoring project in the central Namib. With the support from such high-profile companies as Namdeb and Rio Tinto, and with new legislation on the protection of biodiversity, it is becoming clear that vulnerable species in Namibia, like the Damara Tern, can be adequately protected. In addition to this, the monitoring of Damara Terns has informed authorities on the level of protection that must be afforded this small seabird.
Almost twenty years of monitoring the breeding colonies between Walvis Bay and Swakopmund has resulted in the ringing of over 2 000 individual terns. When ringed birds are resighted, information on parameters such as migration, whether pairs are monogamous, whether they come back to breed within the same areas, and much more is gained. After the long breeding season has ended, the parents and the small percentage of surviving flighted chicks, make the 4 000-kilometre journey to West Africa to spend their winter along the coast of countries such as Cameroon, Nigeria, Benin and Ghana.
During a Damara Tern survey in Lagos, Nigeria, in August 2008, I observed five individual Damara Terns that were wearing colour rings. All of these came from Namibia. However, one individual had a colour ring combination that was unique to only one bird first ringed as a breeding adult at a breeding colony near Swakopmund in 2003. It was subsequently recaught within metres of its previous nest during the breeding season of 2007. After it was sighted in Lagos, Nigeria, it was caught again near the same nest site at the end of 2008. Other migration records include a Damara Tern seen in Gabon in 2005 that was ringed as a chick in 2001, and a Damara Tern that was seen in Benin in 2004 that was ringed as a chick in 2001. The oldest Damara Tern recaught was 15 years old, a tern that was ringed as a chick in 1993, was recaught as a breeding adult in 2004, and again in 2008.
This information, along with newly acquired information regarding breeding populations and areas in the Sperrgebiet, is greatly increasing our understanding of the biology and vulnerability of this special little seabird that holds both cultural and biological significance in our country. It is species like these, that are unique and almost holistically belonging to our country, that should be given special attention and pride.
This article appeared in the 2009/10 edition of Conservation and the Environment in Namibia.
