From: Bird Conservation Newsletter THE TRANS-OKAVANGO TRANSECT

Okavango Delta Wetlands research trip. The Trans-Okavango Transect is the brainchild of Maun businessman, Lars Elvenes – it is a scientific, data-collecting expedition that traverses the Okavango from Maun to Mohembo. The transect takes 8 days to complete, and was undertaken between the 15th and 23rd of September this year. It is supported by BirdLife Botswana and the Harry Oppenheimer Okavango Research Centre (HOORC); BirdLife Botswana was of course responsible for documenting the birdlife in the variety of habitats encountered, while a small team from HOORC monitored water quality, and collected samples of aquatic invertebrates and fish for analysis back at the Centre.

 

Tsogo Maiphetho undertook the bird monitoring for BirdLife Botswana. Among other things, he conducted African Waterbird Census (AfWC) transects along all major waterways. Some of these were existing transects that have been counted regularly since the 1990s, but many were new and added substantially to our coverage of the Delta.

 

Several African Fish-Eagle nests were recorded during the transect and will be monitored annually as part of our Okavango Delta Important Bird Area (IBA) monitoring, to determine breeding success of this raptor which is at the top of the food chain. Fish-Eagles are being used as environmental indicators in other parts of Africa, and could serve the same purpose in the Delta since they are conspicuous and well-known.

 

At the overnight stops, in the late afternoons and early mornings, comprehensive checklists of birds present were made and entered into Botswana Tickbird, BirdLife Botswana’s web-based bird monitoring system. These records are available to all interested persons by visiting the site www.worldbirds.org/Botswana.

 

Highlights of the transect from a birding point of view were the following: The Boro heronry is very active - over 150 nests were counted with Great Egrets incubating, and 18 nests with Rufous–bellied Heron chicks. Only five nests of Reed Cormorants were seen, although it is suspected that larger numbers of this species are breeding – visibility in the reeds is not good. Six Slaty Egrets were counted at the site, and may be breeding there again. Dozens of Black–crowned Night–Herons were present, and these were probably just roosting in the reedbed. This site is worthy of special protection.

 

African Skimmers, a Near Threatened species, were found breeding at Xigera Lagoon and along the Phillipo Channel in significant numbers. However, there were fresh tracks of Water Monitors visiting nests at these sites and Marabou Storks were also seen, posing a threat to these breeding birds. The site at Xigera lagoon is however free from human disturbance. The trip was extremely worthwhile in terms of new baseline information gathered, but the real value will show when the transect has been repeated over a period of several years. Special thanks are due to Lars Elvenes for inviting BirdLife Botswana to participate in this project.