Site description The National Park is a combination of Lakes Abijatta and Shalla, and the land between and around them, in East Shewa Zone. The park is 56 km south-west of Lake Ziway and to the west of the main Mojo–Moyale road. Both lakes are without outlets, and the water is alkaline. Lake Abijatta is very shallow (up to 14 m), while Lake Shalla, in the crater of an extinct volcano, is very deep (up to 266 m). Three rivers, the Gogessa, Bulbula and Hora Kelo, feed Lake Abijatta. The lake had an area of 19,600 ha, a shoreline of 60 km and was full of fish, but by 1995, it had shrunk dramatically and no fish-eating birds were seen. Water is being removed from the lake to feed a soda-ash extraction plant, and from the Bulbula river for irrigation. Fish and aquatic plants now regularly occur only around the mouth of the Bulbula and Hora Kelo rivers. The shoreline is gently sloping. The nearby Acacia woodland used to have a more or less continuous (25-m-high) canopy, but most of the trees have been felled and turned into charcoal or sold as fuelwood. Lake Shalla is south of Lake Abijatta and divided from it by a narrow strip of higher land, part of the old crater rim. Two rivers feed the lake. It has an area of c.33,000 ha and a shoreline of 118 km. It has several hot, somewhat sulphurous springs around the shore, and nine islands of which at least four are important breeding sites for birds. Bulrushes grow where the hot springs and rivers enter the lake, but most of the shore comprises steep cliffs, thus there is little place for wading birds and there are no fish. The vegetation to the east and south of the lake is Acacia–Euphorbia savanna, the most common trees being the woodland Acacia spp. (A. etbaica and A. tortilis) and Euphorbia abyssinica, and bushes of Maytenus senegalensis. The woodland around the lakes is important in keeping the highly fragile soil structure intact. In undisturbed/ungrazed areas there is a rich grass and herb flora.
Key Biodiversity See Box and Table 3 for key species. Over 400 species have been recorded from the park. The park is at one of the narrowest parts of the Great Rift Valley, a major flyway for both Palearctic and African migrants, particularly raptors, flamingos and other waterbirds. Among the globally threatened species known from the park are: Aquila heliaca (a rare passage migrant); Falco naumanni (an uncommon passage migrant with a few wintering); Circus macrourus (fairly common passage migrant, with a few wintering); and Acrocephalus griseldis (status unknown). Glareola nordmanni has also been recorded. Fish-eating birds have mostly abandoned the park since the fish in Lake Abijatta died out. However, huge numbers of many wetland species remain, such as Phoenicopterus ruber, P. minor (the numbers of which fluctuate), Anas clypeata and Charadrius pecuarius. The fringes of Lake Abijatta form an important feeding and resting ground for waders and ducks, particularly Anas clypeata, Recurvirostra avosetta, Calidris minuta and Philomachus pugnax. Smaller insectivores, such as Motacilla flava and Hirundo rustica, have also been recorded in massive numbers. The islands of Lake Shalla used to be important breeding sites for cormorants, storks and pelicans, and colonies of Phalacrocorax carbo and small numbers of Pelecanus onocrotalus still occur. One endemic, Poicephalus flavifrons, and five Afrotropical Highlands biome species have also been recorded. Among the unusual visitors to Lake Abijatta are Calidris alpina, C. melanotos, Charadrius mongolus, C. alexandrinus, Pluvialis fulva, P. squatorola, Phalaropus lobatus, Glareola nordmanni, Grus carunculatus (five in 1991–1992), Netta erythropthalma, Larus ichthyaetus and L. cachinnans.
Non-bird biodiversity: None known to BirdLife International.