Vanishing Blue Cranes baffle bird researchers

THE drastic dwindling in Blue Crane numbers in the Etosha National Park and surrounds is puzzling researchers of the Namibia Crane Working Group.

According to researchers Mike and Ann Scott, a recent ground and aerial survey found only 12 Blue Crane adults and five chicks in the park and surrounding areas.The Blue Crane is a vulnerable species, especially in Namibia where only about 60 birds, out of a total global population of about 20 000, are found. Most Blue Cranes are found in South Africa. Researchers say the isolation of the Namibian sub-population of about 60 birds and their survival in an arid, predator-rich environment, within the Etosha and Lake Oponona wetlands north of Etosha, ‘pose a conservation enigma’.The researchers speculate that it appears as if there is a core group of birds that breed in Etosha and a ‘floating’ population of non-breeding birds, both flocks consisting of 20 to 30 individuals, and it could be that the floating group has temporarily found a suitable habitat elsewhere, in what they hope is a crane-friendly area. They doubt that the missing Blue Cranes have joined South African flocks. However, they say it is likely that the high rainfall and flooding of northern Namibia could also account for the missing birds.Ann noted that these are preliminary findings and they will do further surveys. She called on the public to report any sighting of Blue Cranes. But she said they should not confuse Blue Cranes with the Grey Heron, as they look alike.According to the International Crane Foundation (ICF), the Blue Crane is a bird of dry grasslands and other upland habitats. Where shallow water is available, Blue Cranes will roost and feed. The major threats to the Blue Crane are poisoning, habitat change and powerline collisions. The aerial survey also recorded 11 Wetland Cranes and one Southern Grey Crowned Crane in the surveyed areas.The survey was funded by The Overberg Explorer and the Wilderness Trust, with logistical support from the Ministry of Environment and Tourism. The Namibia Blue Crane Project was launched in April 2006 by the Namibia Crane Working Group of the Namibia Nature Foundation (NNF), and forms part of the Namibia Crane Action Plan.Major findings to date are that after high count of 80 in 1992, 49 adults and 11 juveniles (60) in 1994 and (6) adults plus 7 juveniles, 67 in April 2006, total numbers have subsequently not reached more than 30 birds. The Scotts say this could be related to good rains in 2006, 2008 and 2009. absalom@namibian.com.na