Promoting Biodiversity Conservation and Sustainable use in Rwanda WATERBIRD ASSESMENT AT LAKE IHEMA IN AKAGERA NATIONALPARK, RWANDA.

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1 Association pour la Conservation de la Nature au Rwanda (ACNR) Promoting Biodiversity Conservation and Sustainable use in Rwanda WATERBIRD ASSESMENT AT LAKE IHEMA IN AKAGERA NATIONALPARK, RWANDA Technical Report By: Serge Nsengimana, Marc Ndimukaga, Claudien Nsabagasani, Julia Ritsche and Hannes Bruhnke April 2010

2 Acknowledgement This assessment involved different stakeholders including international organizations, donors, local government and local people. Our thanks are firstly addressed to Birdlife International and wetland International for initiating the water birds counting scheme. The Wetland International provided the financial support, under the Wings over Wetlands project to Association pour la Conservation de la Nature au Rwanda (ACNR) for the achievement of the bird assessment and capacity building at Lake Ihema. Our thanks are directed to the NABU Rheinland-Pfalz for a support of used material in this activity. The RDB/ Tourism and conservation authorised authorized our work at Lake Ihema in Akagera National Park. We take this opportunity to thank the Akagera National Park particularly Mr. Rogers Gakwerere, the tourism warden and Mr. Buda Patrick for their kind assistance and participation during the bird count. May our boat driver find here our sincere thanks.

3 INTRODUCTION: The annual waterbird count is carried out under the umbrella of the International Waterbird Census (IWC) and in particular by The African Waterbird Census (AfWC), the co-ordinated international waterbird census for Africa. Participants were ACNR staff mebers and volunteers and experts from the Rwanda Development Broad (RDB) / Tourism and Conservation. Photo: Waterbird Census team These waterbird count is accomplished every year to analyse (I) the population size of different birds, to (II) ascertain variabilities in population size and (III) to understand bird migration and thereby effected changes by birds arriving or birds flying away. Our recorded birds are shown in Table 1. SURVEY AREA: Lake Ihema is located in Eastern Province, close to the Tanzanian Border and the biggest

4 lake in Akagera National Park. The area inside the National Park is formed by many lakes and marchs which were created by volcanic activites in the tertiary. Furthermore the Akagera-river passes through the edge of the park which is later flowing into the nile. The average annual precipitation is in between 650 and 850 mm/a (Vande weghe 1990) and the altitude ranges between 1300 m and 1400 m. The Vegetation around the Lake is dominated by Cyperus papyrus with stands of Dryopteris spp. and Ipomoea fragrans climbing up to 4 m on papyrus. The species Polygonum pulchtrum and Phragmites mauritianus are sometimes associated with Papyrus, while Echinochloa spp., Hydrocotyle ranunculoides and Dissotis incana are present along outer margins of the papyrus in some areas. Partly papyrus inlets are occuring in the lake. Woody species were found in the papyrus swamp around the lake. The most important are the extensive stands of Ficus spp. which are rooted in the shallow parts of the swamp. There are also thickets of Phoenix reclinata. The vegetation on the floating swamps is dominated by the Cyperus papyrus, Typha latifolia and Thriumphetta spp.. The lake is locally covered by Nymphaea nouchalli, a water plant whose leaves are swimming on the water surface. The south coastline of the lake is covered by Papyrus as well as many wooden species. The Nyarabiyoro island inside the lake, whose coastline was also implemented in our bird count, is particularly covered by different wooden species and seemed to be a very adequate place for breeding as well as place for spending night of many birds. The north shore of the lake is dominated by large extensions of Papyrus. Our recorded area is shown in figure 1 and was designed by recorded GPS-Points during our waterbird assemsment. MATERIAL AND METHODS: The waterbird count were accomplished by using boat, binocular and technial literature. Altogether three different counts were arranged. The first one was done between 9.00 am and 2.00 pm along the whole south coast of lake Ihema. All visibly birds inside the virine vegetation and above the open water were counted. From 5.00 pm till 6.00 pm the Nyirabiyoro island inside the lake was surrounded and all birds inside the vegetation and above the open water were counted. For extraordinary large accumulation of birds the number per species was estimated. The third bird count was done during the next morning from 09:00 am to 2.00 pm along the north coastline from Lake Ihema.

5 During every bird asses, birds were counted from all participants and were listed by three different observers to avoid significant mistakes. Table 1 shows the counted birds from all three trips accumulated but seperated for every species. Additionally informations about migratory status are added. RESULTS AND DISCUSSION: Table 1 shows all the counted population per each bird species and is also giving informations about the migratory status. Altogether we recorded 28 species and 2053 birds. The population was dominated by the Cattle Egret with 663 individuals. During observing birds, the sky was just partly cloudy initially and mostly cloudy from the middle to the end. The visibility was good and wind was low all the time. Sometimes it was raining a very little but for just some minutes. The largest population of birds were recorded at the Nyirabiyoro Island, during our afternoon bird assesment between 5.00 and 6.00 pm. Either birds were sitting inside the riverine vegetation or were flying near the costline as a covey or in smaller groups. On the verge of twilight more and more birds were collecting inside the vegetation. Given that no predators are excisting on the island many birds are breeding in these riverine vegetation and use it as place to spend thier night. Table 1: Counted Birds Species: Sum (Average): Status: African Dater (Anhinga rufa) 336 African Fish Eagle (Haliaeetus vocifer) 25 African Jacana (Actophilornis africanus) 5 African Open-billed Stork (Anastomus lamelligerus) 32 Black Crake (Amaurornis lavorostris) 5 Black-crowded Night-Heron (Gorsachius leuconotos) Black-headed Heron (Ardea melanocephala) 2 Cattle Egret (Bubulcus ibis) 663 Common Squacco Heron (Ardeola ralloides) 47 Egyptian Goose (Alopochen aegyptiacus) 2 Eurasian Marsh Harrier (Circus aeruginosus) 2 Goliath Heron (Ardea goliath) 6 23

6 Great Cormorant (Phalacrocorax carbo) 445 Great Egret (Casmerodius albus) 2 Great White Pelican (Pelecanus onocrotalus) 2 Grey Heron (Ardea cinera) 1 Hadada Ibis (Bostrychia hagedash) 13 Intermediate Egret (Mesophoyx intermedia) 2 Long-tailed Cormorant (Phalacrocorax africanus) 248 Marabou Storck (Leptoptilos crumeniferus) 9 Osprey (Pandion haliaeetus) 4 Pied Kingfisher (Ceryle rudis) 145 Pulm-nut Vulture (Gypohierax angolensis) 1 Purple Heron (Ardea purpurea) 1 Sacred Ibis (Threskiomis aethiopicus) 2 Spur-winged Lapwing (Vanellus spinosus) 10 Striated Heron (Butorides striatus) 10 Water Thick-knee (Burhinus vermiculatus) 10 TOTAL: 2053 Particularly large populations of birds were recorded for the Cattle Egret, the African Darter the Great Cormorant, the Long-tailed Cormorant and the Pied Kingfisher. The letter was also recorded very often at Lake Rweru in January 2009 (Ndimukaga 2009) as well as recorded in high populations in Lake Mugesera (see: Birds assessment and capacity building at Lake Mugesera (Nsabagasani 2009). However the African Darter and Great Cormorant were not recorded at neither Rweru or Mugesera in 2009 and only the Longtailed Cormorant was observed quite temporary. Comparing to these past counts in January 2009, migratory backgrounds are assumed. All the other recorded birds were found in similar population sizes like in However fishing is not prevent completely and legal for some local farmers as a crucial prerequisite to earn their subsistence, negative follows for birds seemed not be provoked.

7 REFERENCES: VANDE WEGHE J.P. Akagera l`eau, l`herbe & le feu, pp 43-44, 1990 NSABAGASANI C., NSENGIMANA S.J., NDIMUKAGA M., RUNYAMBO C. (2009). Birds Assessment and capacity building at Lake Mugesera, Rwanda NDIMUKAGA M., NSENGIMANA S.J., RUNYAMBO I., UWIMANA T., KANAMUGIRE RF. (2009). Lake Rweru waterbird assesment, Eastern Province, Rwanda.