In the present study, a total of 46 bird species under 11 orders and 30 families were recorded from the three wetland habitats. A total of 64 species and 17 families of birds were recorded across the wetlands of eastern Uganda (Sarah et al. 2020). From the Afro-tropical highland wetlands of the Awi zone and Wombera hotspot areas, Northwestern Ethiopia, 84 species and 23 families were recorded (Tesfahunegny 2016). A total of 103 avian species belonging to 47 families and 14 orders were recorded in Lake Hawassa and part of the Eastern Wetland habitats, Southern Ethiopia, during the wet and dry seasons (Gibru and Mengesha 2021). Ninety-five species were recorded from the wetland areas of Tropical Maharashtra, India (Wagh and Prathmesh 2020). Of the 11 orders, the order Passeriformes is represented by the highest number of species (N = 17). The order Passeriformes is the largest and most diverse order of birds, comprising over half of the world’s known bird species (Sibley and Monroe 1990).
This study indicated that the wetlands support a large number of bird species, including two endemic species, the Thick-billed Raven (Corves crassirostris) and the Banded Barbet (Lybius undatus). In addition to this, resident and migrant bird species occur in a significant number, which provides an indication that the area is a satisfactory habitat for resident bird species and a stopover for migrant bird species that can forage, loaf, rest, and refuel their energy. In a similar study that was carried out around Jimma town of BoyeKitto and Kofe wetlands, 107 species of water birds were recorded (Mekonnen and Aticho 2011). The species composition of birds in different seasons was also determined for the study areas. In general, overall bird species diversity was highest during the wet season in all habitats. This is due to the high species richness in this wet season.
According to Borgesio (2004), wetland habitats provide ample food resources such as frogs, worms, and insects to many bird species. This study, however, found that among the three wetland habitats, the highest species diversity was recorded in the Loga wetland habitat. Further, the presence of a variety of vegetation around this wetland is probably a contributing factor. Smith (1992) described how food resources are one of the key factors in determining the species diversity in a particular area. On the other hand, in the Hurri wetland habitat, relatively less bird diversity was observed. This might be due to more anthropogenic activities taking place around this wetland habitat. For this reason, birds do not get an adequate place for nesting and breeding. Meyer and Turner (1992) described how the conversion of wetlands for agriculture and industrial ports affects the nesting and breeding sites of many bird species.
The result of species diversity analysis revealed that species composition is different among areas and months because of habitat differences, seasonal movement patterns, local and regional habitat changes, large-scale population changes, and climatic conditions (Ericiaet al., 2005). The present study revealed that the seasonal occurrence of bird species in the three wetlands was different. In general, most bird species were locally common.
A total of 1626 individuals of 57 species of birds were observed during the wet season and 962 individuals of 41 species during the dry season in the three types of habitats of the study area (Table 2). The decline in global bird diversity has been linked to a number of anthropogenic factors, including pollution (Gordon et al. 1998), water fluctuation (Riffell et al., 2001; Timmermans et al., 2008), habitat and landscape configuration, and the influence of the surrounding physiographic matrix (Czech and Parsons 2002). The seasonal occurrence of bird species in the three wetlands was different. This difference might be due to the availability of food resources, habitat conditions, breeding season, as well as the migratory behavior of bird species (Mengesha and Bekele 2008). In a similar way, Gaston and Blackburn (2009) explained that the distinct seasonality of rainfall and seasonal variation in the abundance of food resources resulted in seasonal changes in the abundance of birds. Furthermore, the temporal decoupling of food resources and bird numbers, variable climate harshness in different regions, or individuals' inability to reach isolated areas all have an impact on the migratory bird population (Telleria et al. 2009).
In general, wetlands are important feeding and breeding areas for birds. Farmers around the wetlands cultivate the area during both the wet and dry seasons, with crops such as maize and sorghum becoming the dominant crops in the study areas. At present, the unusually high level of human encroachment has led to a reduction in the size of the wetlands, which has resulted in many areas being under permanent cultivation. Ultimately, this could eliminate the bird’s habitat unless concerned bodies are involved in conservation measures. To conserve the wetlands and the avian population of the study area, a management plan should be prepared emphasizing an avenue for the sustainable utilization of the resources of the wetland without jeopardizing its continued ecological values and function. As with all ecological studies, our study also has some shortcomings during data collection and analysis.