Habitat utilization by birds, hippopotamus (hippopotamus amphibious) and livestock in lake Ol'bolossat, Kenya.

Abstract

The field study was conducted between April and November 1999. The study established the habitat use and activity budget for Red knobbed coots (Fulicata cristata), Egyptian geese (Alopochen aegyptica), Yellow-billed ducks (Anas undulata) and Glossy ibises (Plegadis falcinellus). Habitat use was established based on the number of birds of each species in each habitat type. For all the species, the marshland was occupied by significantly more birds that all other habitats Red Knobbed coot (p=0.0007), Egyptian geese (p=0.001) Yellow billed duck (p= 0.00) and Glossy ibis (p=O.OOO).The marshland was the most preferred habitat type by all the birds. The activity budgets for the birds were obtained usmg the scan sampling method. Among all the birds, feeding was allocated significantly more time; Red Knobbed' coot (p=0.001), Egyptian geese (p=0.001) Yellow billed duck (p=O.OOI)and Glossy ibis (p=O.OOI). The small birds spent more time feeding than bigger birds. Movement and loafmg was common in the early ours of the afternoon. The study also estimated the population size, density, distribution and habitat utilization by hippopotamus (Hippopotamus amphibious). The " hippopotamus population estimates were done tlUough the total count method. The density was established as 1.9 hippos/km'. The distribution of hippopotamus was found to depend on the availability of water. Their foraging habitat is limited to a distance of2.8-3.3 Ian around the Lake. The distance travelled while foraging is related to the availability of resources. The hippopotamus therefore travel long distances when food is scarce. The distances travelled by hippopotamus in eastern and western side were not significantly different (p=O.215) The effect 0f livestock grazing was established using the difference method. The livestock occurs in the wetland in large numbers and they have adverse effects on it. They remove significantly more biomass form the wetland as compared to hippopotamus (p=O.OO1).