Namibia Crane Working Group – Where do the Blue Cranes go?

By Dr Ann Scott, Mike Scott and Dr Conrad Brain, Namibia Crane Working Group

Suddenly the radio receiver crackles – a signal on frequency 151.130, from the crane we captured in Etosha on 23 April 2007. Then a large group of Blue Cranes flashes into view, steel-grey birds standing in steel-grey water, each body arched in a graceful question mark.

We echo the question: where have these birds been during the past dry months when we could not find them in Etosha?

Blue Cranes are critically endangered in Namibia. As with the core population in South Africa, Namibia’s small population of 60 appears to be declining, prompting the NNF Namibia Crane Working Group to initiate a research conservation project in 2006. Combined aerial/ground counts dropped dramatically from 67 birds in April 2006 to only 22 a year later. This trend paralleled increasingly dry conditions as the cranes moved northwards into the Lake Oponono wetlands.

By August 2007, when no cranes were found in Etosha and only 15 at Lake Oponono, we decided to investigate the Upper Cuvelai area in Angola. On 26 September 2007, we took off from Ondangwa and were soon winging over Angola at 250 feet, flying northwards over neat kraals, huge baobabs, makalani palms and other trees, but few people. Some 150 kilometres later, we were over the Parque Nacional da Mupa. The large, greenish Kunene River rushed into view and, as the bushy habitat northwards appeared unsuitable for Blue Cranes, we followed the floodplains across southern Lubango. The scenery was spectacular with lush vegetation, reeds and sandbanks. We spotted African Fish Eagles, Darters, teals, cormorants – but no cranes.

Across the rugged Kunene gorge, we flew on over the Olushandja Dam to Ondangwa, elated but somewhat despondent not to have found any cranes. The midday heat shimmered. We fixed the radio tracking antennae onto the plane’s wings and climbed to 6 000 feet. Finally, over the shores of Lake Oponono, we received the long-awaited signal from our tagged bird.

Shortly before the Angola survey, we received a report of 25–30 Blue Cranes in East Caprivi, about 900 kilometres east of Etosha. Such large-scale movements are uncommon for Blue Cranes. It now seems likely that some or all of these birds had returned and rejoined our tagged bird and the original group of about 30 cranes at Lake Oponono. If not – where did the extra birds come from?

To find answers, we plan to fit two satellite transmitters (PTTs) and additional radio transmitters onto Blue Cranes in April 2008; to build up contacts with Angolan conservationists; and to undertake an aerial survey east of Angola’s Mupa National Park.

This survey highlights the importance of the Lake Oponono area for Blue Cranes during dry conditions, and we need to find ways to promote the protection of this area and Namibia’s small but fascinating Blue Crane population.

We thank our many supporters for their assistance with this survey.

This article appeared in the 2008/9 edition of Conservation and the Environment in Namibia.