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The Forest Birds of Kenya and Uganda
Abstract
Robust and rapid ways of assessing and monitoring forest biodiversity are increasingly necessary. To this end, we present a classification of forest birds in Kenya and Uganda into three simple categories: forest-specialists (FF species), forest generalists (F species) and forest visitors (f species). FF and F species, but not f species, are dependent on forests. Out of 479 forest birds in the two countries, 214 are FF, 156 F and 109 f species. Forest-dependent birds, and particularly forest specialists, are less widespread than forest visitors. Uganda has 420 forest birds compared to Kenya's 335, and a higher proportion of forest specialists: this reflects differences in forest structure and biogeography, rather than the area of natural forest. Using this classification allows species lists and densities to be interpreted more meaningfully. The number of FF species is an initial measure of a forest's relative conservation importance, while the proportion of FF, F and f species and their relative abundance will shift according to changes in forest structure.
... Forests provide multiple ecosystem services and support a large proportion of the Earth's terrestrial biodiversity [3,6,34]. Global forest loss has increased dramatically in the last few decades according to FAO [21], leading to a growing focus on the birds inhabiting these ecosystems [4]. Studying forest birds is crucial for two main reasons. ...
... Species that primarily eat fruits (frugivores) will aid in seed dispersal whereas those that eat insect (insectivores) contribute to invertebrate control including pests [9,36,64]. For habitat functional guilds, we relied on the forest classification done by Bennun et al. [4] on forest bird species of Kenya and Uganda. Based on their habitat preferences, we classified birds into three categories: forest specialist, forest generalist, and forest visitors. ...
... However, if the interiors of these forests remain relatively pristine, specialists may continue to thrive. Typically, forest specialists tend to use the core of the forests, making them less vulnerable to human developments occurring at the forest edges [4]. Forest visitors typically occupy edge habitats or secondary growth areas at the periphery of forests. ...
Forests provide vital ecosystem services and support a significant proportion of Earth's terrestrial biodiversity. Despite their ecological importance, global deforestation has accelerated in recent decades, posing a grave threat to biodiversity. Birds within these ecosystems are particularly important for conservation efforts, as they serve as indicators of forest health and overall biodiversity. In this study, we examined the relationship between species richness and functional metrics of forest-dependent birds in Kenya, focusing on the impact of habitat degradation and deforestation as environmental filters. Our objective was to determine how forest loss influences species richness and functional diversity indices, potentially leading to increased functional biotic homogenization. Using citizen science data from the Kenya Bird Map, we classified birds into three categories: forest specialists, forest generalists, and forest visitors. Our findings revealed a decline in both taxonomic richness and functional diversity, alongside an increase in functional evenness in response to forest loss, supporting the hypothesis that deforestation drives biotic homogenization. Forest visitors displayed a heightened sensitivity to forest loss, likely due to the reduction of edge habitats and increased human disturbances, underscoring the need for targeted conservation strategies. Our results underscore the critical role that policies like the Kenyan Forest Policy Act can play in mitigating anthropogenic pressures on forests. By highlighting the importance of preserving mature forests and maintaining forested lands, our study emphasizes how such policies could support biodiversity conservation and sustain essential ecosystem functions within Kenya's diverse forest ecosystems
... Table 3.3 -List of bird species identified as potential seed dispersers in the degraded areas and guildlevel assignment for each species. Guild levels were attributed based on Bennun et al. (1996) classification, described in section 2.3.2. and new classifications are marked with symbol '*'. .......... 13 Table 3.4 -Summary of the best models for potential dispersers' abundance, species richness, species, families and guild levels. ...
... For instance, larger birds are expected to move and forage over larger areas, having greater home-ranges (Jetz et al. 2004) and holding potential for long distance dispersal (Levey 1987). In addition, different species hold different levels of dependency upon relatively undisturbed forest (Bennun et al. 1996). Forest specialists rarely visit the outside of undisturbed forests and hence offer limited dispersion services to these areas, whereas forest generalists frequently move between different habitat patches, becoming more interesting dispersers in degraded areas (Wunderle Jr 1997). ...
... The different guild levels modelled followed the classification made by Bennun et al. (1996), who gathered information concerning habitat requirements of forest birds from Eastern Africa (Kenya and Uganda). The authors classified bird species' habitat requirements in three different levels according to the different levels of human disturbance and impact on the forest structure: ...
Human action has been shaping the landscape of tropical regions with increasing deforestation rates and conversion of forest patches into agricultural land. Natural forest succession in degraded areas is slow and depends largely on the movements of fruit eating animals, such as birds, which disperse seeds from the forest interior. However, forest fragmentation and isolation limit the process of seed dispersal and
the reduced number of dispersers present in degraded areas can abridge the future of tropical forests. In Guinea-Bissau, slash-and-burn agriculture and the conversion of forest into cashew tree orchards are the main threats to this country’s forests. In the present days, mature sub-humid forest can only be found in the south-western region of the country, in Cantanhez National Park (CNP).
The main goal of this study is to understand the role of seed dispersal by birds in degraded areas of CNP and to contribute with management measures that promote their presence in these areas, so that natural regeneration and conservation of forests is improved.
To achieve this, I aimed to determine which plant species are being dispersed from mature forest to degraded areas and understand whether dispersed seeds are viable and can potentiate forest regeneration.
Seed traps were assembled in degraded areas to collect bird droppings and seeds. After identification, seeds were subjected to germination trials in the lab. In order to identify potential avian seed dispersers and the landscape elements that attract different dispersers to these areas, focal points were conducted at dawn and dusk, in trees of different species and in open fields. Landscape and tree elements that may influence the presence of birds in these areas were measured and registered.
Twenty-one bird species were identified as potential seed dispersers. Weavers (Ploceus sp.), the African Green-pigeon (Treron calvus) and doves (Streptopelia sp.) were the most abundant, even if probably not the most efficient. Recognized as good dispersers and also abundant in the area, were Bulbuls, Violet-backed starlings and Hornbills. The first two are considered forest visitors, seeming to benefit from taller trees. Tree height, is also an important driver of faeces and seed deposition and tall trees offer better predator lookouts, foraging opportunities. Hornbills are known to disperse a wide variety of seeds, including large ones, but seem to have a greater impact on forest regeneration near forest edges.
Active management actions to promote forest regeneration in degraded areas should encourage that scattered native trees or small patches of trees are left in the degraded areas. Tall and large trees such as trees belonging to the Bombacaceae family should be favoured, but the presence of any perch has been proven to be beneficial to attract seed dispersers and increase seed deposition. The presence of native fruit trees, such as Fig trees (Ficus sp.) and Bark Cloth trees (Antiaris toxicaria), and a higher vegetation complexity also seem to attract a wider diversity of dispersers and increase faeces and seed deposition and should thus be promoted. These management actions should enhance seed dispersal functions and
contribute for the regeneration and conservation of forests of the CNP and elsewhere in West Africa.
... We examined bird species richness along the condition gradient categorized as undisturbed (tiers 1 and 2), moderately disturbed (tiers 3 and 4), and severely degraded (tiers 5 and 6; Davies and Jackson, 2006). The data were further examined using a simple classification system for East African Forest birds developed by Bennun et al. (1996). The system goes further than a simple species list and detects subtle differences between forest avifauna in both space and time by classifying them based on their forest dependency. ...
... They are almost always more common in nonforest habitats, where they are most likely to breed. We used proportions of birds in each category in the classification system to develop indices that indicate various forest conditions (see Furness and Greenwood, 1993;Bennun et al., 1996;Bryce et al., 2002). ...
... There must be a long-term and extensive monitoring approach that considers ecological health that includes the suite of ecological components in watersheds or catchments (Buss et al., 2015). Many of the terrestrial biological components used to describe ecological conditions that have been used elsewhere including the use of bird feeding guilds, abundance, and distribution to indicate various forest conditions (Furness and Greenwood 1993;Bennun et al., 1996;Bryce et al., 2002), how vegetation is important in supporting ecological processes and functions in landscapes (Handa et al., 2012;Riis et al., 2020), the strong interactions that exist between macrofungi and their environments (Mangan et al., 2010;Segnitz et al., 2020), and herpetofauna are very sensitive sentinels of environmental change due to their permeable thin skin and complex life cycle that makes them vulnerable to chemical and physical changes in both terrestrial and aquatic habitats (Bell and Donnelly, 2006). A program with several biomonitoring taxa is likely to bring on board many stakeholders and in doing so, assist in overcoming challenges that bewilder biomonitoring programs such as poor knowledge of biodiversity especially in developing countries, as well as increasing public awareness on the importance of river ecosystems and ecosystems services as such the need for motivating landscapes rehabilitation projects (Leigh et al., 2019). ...
The biological condition gradient (BCG), a scientific framework that describes the change in ecosystem characteristics in response to human-induced levels of stressors, was modified and used to characterize watershed habitats in the Upper Tana River watershed, Kenya. The inbuilt utilities of BCG, including its simplicity, versatility, and its robust nature, allowed its use by seven taxonomic groups of macroinvertebrates, diatoms, fish, herpetofauna (amphibians and reptiles), plants, macrofungi, and birds to assess and monitor landscape conditions in both terrestrial and aquatic habitats. The biological data were described using taxa abundance distribution measures followed by multivariate analyses to determine their relationship with water or soil quality and thereafter assessment of taxa tolerant levels in response to environmental stress and disturbances. Preliminary findings reported that the taxonomic groups complemented each other, with each taxonomic group reliably assessing ecological conditions to a certain degree that supported assigning all 36 sampled sites into BCG tiers. The BCG models developed for all taxonomic groups assisted in the identification and selection of taxa indicating varying levels of landscape conditions. These taxa, referred to as flagship or indicator taxa, assist in simplifying the BCG model and, hence, are possible for use by parataxonomists or ordinary citizens to assess and monitor the ecological health of habitats under consideration. Furthermore, the capability of BCG models to assess landscape conditions shows how they can be used to identify important habitats for conservation, direct investment for restoration, and track progress.
... With African Broadbill Smithornis capenses and Stripe-faced Greenbul Arizelocichla striifacies observed by J. Kiure but not by us and Kipengere Seedeater Crithagra melanochroa collected by G. Heinrich but not recorded by us, the total number of forest bird species known from Mdando Forest is 64 (Appendix 1). Of these, 36 are forest specialists, 24 forest generalists and 4 forest visitors according to the categorizations established by Bennun et al. (1996) and Burgess et al. (2007). Among the forest generalists we recorded one Palaearctic migrant, the Eurasian Blackcap Sylvia atricapilla. ...
... Also included are approximate estimates of abundance based on how often a given species was observed, heard and/or caught in mist-nets. Taxonomy and nomenclature follow Gill et al. (2023) and definitions of abundance and forest dependence follow Bennun et al. (1996) and Burgess et al. (2007) as follows: o = recorded, xx = common in the right habitat, x = rare/low density species, FF = Forest specialist strictly confined to forest, F = Forest generalist mainly in forest, f = forest visitor. ...
We conducted an avian survey of Mdando Forest in Tanzania´s Southern Highlands in September and November 2022, and May 2023, using mist nets and opportunistic observations from camps inside the forest at 1750 m, 1950 m and 2050 m elevation. We recorded 61 species which included nine species that previously have not been reported from Mdando, including Black-headed Apalis Apalis melanocephala and Sharpe's Akalat Sheppardia sharpei. Conversely, we failed to find three forest species that are recorded from Mdando. Of the total of 64 bird species known from the forest, 36 are classified as forest specialists, 24 are forest generalists and four are forest visitors. The forest avifauna included range-restricted species such as Iringa Akalat Sheppardia lowei and Spot-throat Modulatrix stictigula. The non-forested Makambako highlands (the "Makambako Gap") have often been seen as a faunal barrier separating the Southern Highlands from the more species-rich East Arc Mountains. However, 36 of the 44 montane forest specialists known from the Udzungwa Mountains, the southernmost and closest area of the East Arc Mountains , have now been recorded from Mdando Forest, which shows that there is a large overlap in the montane avifauna on both sides of the Makambako Gap, suggesting a comparatively recent forest connection.
... The community of birds in the Virunga volcanoes consists of forest interior species, forest generalist species, forest visitors, and species that use other non-forest habitats [47]. A total of 294 bird species across 66 families have been recorded in the Virunga volcanoes including 18 species that are endemic to the Albertine Rift ecoregion [38]. ...
Niche theory predicts that ecologically similar species can coexist through multidimensional niche partitioning. However, owing to the challenges of accounting for both abiotic and biotic processes in ecological niche modelling, the underlying mechanisms that facilitate coexistence of competing species are poorly understood. In this study, we evaluated potential mechanisms underlying the coexistence of ecologically similar bird species in a biodiversity-rich transboundary montane forest in east-central Africa by computing niche overlap indices along an environmental elevation gradient, diet, forest strata, activity patterns and within-habitat segregation across horizontal space. We found strong support for abiotic environmental habitat niche partitioning, with 55% of species pairs having separate elevation niches. For the remaining species pairs that exhibited similar elevation niches, we found that within-habitat segregation across horizontal space and to a lesser extent vertical forest strata provided the most likely mechanisms of species coexistence. Coexistence of ecologically similar species within a highly diverse montane forest was determined primarily by abiotic factors(e.g. environmental elevation gradient) that characterize the Grinnellian niche and secondarily by biotic factors (e.g. vertical and horizontal segregation within habitats) that describe the Eltonian niche. Thus, partitioning across multiple levels of spatial organization is a key mechanism of coexistence in diverse communities.
... Data analysis: The list, full scientific names and biogeographical status of the bird species are according to Gill F et al., (2022). The preferential habitat of the species is indicated according to Bennun et al., (1996) andYaokokoré (2001). The characterization of bird species based on their abundance has been done according to Thiollay (1986). ...
Objectives: A bird study was conducted from January to December 2017 on the rice fields of Nanan, Petit Bouaké and Zatta in Yamoussoukro District. The aim of this study was to identify birds of rice fields in the pre-forest areas of Côte d'Ivoire.
Methodology and results: During twice-monthly visits, all birds seen or heard, posed or flying in the rice fields, were recorded. A total of 95 bird species were recorded. They belong to 37 families divided into 15 orders with an abundance of 57172 birds. The most represented family is that Ardeidae with 11 species and the Village Weaver Ploceus cucullatus (Müller, 1776) is the most abundant species with a relative frequency of 57.84%. Open-space birds (59%) dominate rice fields and resident species account for 56% of the bird population. The composition and abundance of the species in the rice fields change according to the development of the rice rather than the seasons.
Conclusions and application of the results: This study shows the species of birds that depend on rice fields during an annual cycle. The results obtained will allow us to know and monitor these species in this particular agro ecosystem. This will also help to train and sensitize rice farmers to better manage these birds, which they very often consider to be harmful to their rice fields.
This study investigates the impact of land‐use changes on avian diversity in an agricultural landscape ecosystem in the Usambara Mountains, northeastern Tanzania. The East Usambara Mountains have lost a significant part of their original natural forests. On its southern part, the main forest block is found in Amani Nature Forest Reserve, while the rest of the landscape is fragmented into agricultural mosaics. The study, conducted from 2020 to 2023 using point count observations, documents the avian diversity in different habitats within agricultural landscapes, considering rainy seasons' effects. A total of 4107 individual birds representing 121 species from 39 families were recorded, with notable variations in species diversity across different habitats. Agroforestry systems demonstrated higher avian diversity than forest remnants, agriculture, tea plantations and shrubland. Proximity to forest positively influenced bird diversity, with a significant proportion of true forest species highlighting the importance of intact forest ecosystems. Seasonal variations were evident, with the short rainy season exhibiting higher species richness in certain habitats. The findings of this study underscore the need for conservation strategies that prioritise forest protection and restoration while promoting sustainable agroforestry practices.
Abandoned post‐quarry sites have potentiality to be remodeled into natural‐wilderness areas, a desire especially in rapidly urbanizing and transforming landscapes. However, paucity of ecological information on post‐quarry sites limits nature‐based restoration, especially in the sub‐Saharan tropical landscape. This study investigated avifauna composition of post‐quarry sites in Ndarugu, Kenya, relative to non‐quarried sites for conservation role prioritization. Birds were censused in 166 point count stations using the fixed‐radius distance method. Land use land cover types within each point provided the variables for explaining bird occurrence. Observed bird species were classified into functional guilds, avifaunal composition assessed, and bird data subjected to multivariate analysis. In total 158 species, 128 in post‐quarry and 123 in non‐quarried sites, were recorded. Bush‐ and forest‐related species were dominant, constituting over 55% of total observed birds, in both site categories. Six wetland‐related species were detected only in quarried sampling sites. Mann–Whitney statistical tests returned a significant effect of land use category on bird species richness, abundance, and diversity, all higher in post‐quarried than in non‐quarried sites ( p < 0.05). Emergent natural shrubs, quarry cliffs, and cultivated farms were most influential to bird community structuring. Nonmetric multidimensional scaling and cluster analysis revealed four functional groups of birds whose species richness increased with number of post‐quarried sampling sites in a cluster. Unique physical features of post‐quarry sites and emergent vegetation types, can be partially mimicked in nature‐oriented rehabilitation planning for long‐term social and ecological benefits.
Les oiseaux d’eau constituent une des composantes remarquables de la faune aquatique. Cependant, les oiseaux d’eau du nord de la Côte d’Ivoire et en particulier ceux du Parc National de la Comoé sont méconnus. L’objectif de ce travail est d’améliorer les connaissances de cette avifaune pour une meilleure gestion de ces espèces. Ces améliorations reposent sur des données qualitatives et quantitatives. Un inventaire ornithologique a été mené de septembre 2017 à août 2019 au Parc national de la Comoé sur les oiseaux d’eau dans trois différents types d’habitats (les mares, les forêts galeries et les savanes). Pour sa réalisation, la méthode des points d’écoute et des marches lentes marquées d’arrêts le long de la Comoé et de ces principaux affluents ont été appliquées. À l’issu de ces inventaires, 47 espèces d’oiseaux d’eau appartenant à 18 familles ont été inventoriées. Les non-Passériformes avec 42 espèces représentent 89,36% de la richesse spécifique. Au niveau des familles, celle des Ardeidae représente 23,81% de la richesse spécifique totale avec 10 espèces. Ce sont 2685 individus qui ont été observés sur l’ensemble de des sites. Le Héron garde-bœuf Bubulcus ibis (570 individus, 21,23%) et l’Ombrette africaine Scopus umbretta (193 individus, 07,19%) sont les espèces comptant les plus grands effectifs des oiseaux d’eau. Les espèces d'oiseaux d'eau ont plus fréquenté le parc en saison sèche (octobre et avril) et les abondances les plus importantes se situent entre décembre et mars. Au titre de l’utilisation des habitats par les oiseaux d’eau, il s’observe une préférence de ces derniers pour les forêts galeries. Seule la Cigogne épiscopale Ciconia episcopus est considérée comme proche de la menace selon l’UICN (2022). Waterbirds are a remarkable component of aquatic fauna. However, little is known about the waterbirds of northern Côte d'Ivoire, and in particular those of the Comoé National Park. The aim of this work is to improve knowledge of this avifauna in order to improve the management of these species. These improvements are based on qualitative and quantitative data. An ornithological survey was carried out from September 2017 to August 2019 in the Comoé National Park on waterbirds in three different types of habitats (ponds, gallery forests, and savannahs). The method used was count points and slow walks with stops along the Comoé and its main tributaries. As a result of these surveys, 47 species of waterbirds belonging to 18 families were inventoried. The non-Passeriformes, with 42 species, accounted for 89.36% of the species richness. In terms of families, the Ardeidae family represented 23.81% of the total species richness, with 10 species. A total of 2,685 individuals were observed at all the sites. The Cattle Egret Bubulcus ibis (570 individuals, 21.23%) and the Hamerkop Scopus umbretta (193 individuals, 07.19%) were the species with the highest numbers of waterbirds. Waterbird species visited the park most during the dry season (October and April), with the greatest abundance between December and March. In terms of habitat use by waterbirds, there is a preference for gallery forests. Only the Woolly-Necked stork Ciconia episcopus is considered to be close to threatened according to the IUCN (2022).
Mechanized selective logging in tropical rain forest typically removes only a small percentage of timber trees, but incidental damage may be severe. In a West Malaysian dipterocarp forest, extracting 3.3 percent of trees destroyed 50.9 percent, and damage was spread equally among all tree taxa and all size classes. The overall availability of food sources for frugivores and folivores is thus drastically reduced, even where timber trees are not themselves used by animals. To some extent, the initial loss of food sources may be buffered by increased reproductive and vegetative activity of those trees that remain.
In lowland dipterocarp forest in Sabah, Malaysia, most primary forest bird species were present in areas selectively logged eight years previously. However, certain taxa, notably flycatchers, woodpeckers, trogons and wren-babblers, became comparatively rare. In contrast, nectarivorous and opportunistic frugivorous species were significantly more abundant. Few species appeared to change foraging height, but netting rates suggest that the activity of some species had increased, or that some birds ranged over larger areas after logging. Although there is still much to be learned about the survival of birds in logged forest, large areas of this habitat are important for bird conservation. However, the susceptibility of logged forest to fire, and our present incomplete understanding of bird behaviour and population dynamics in logged forests mean that they should not be considered by conservationists as alternatives to reserves of primary forest.
Mann, Clive F. 1985. An avifaunal study in Kakamega Forest, Kenya, with particular reference to species diversity, weight and moult. Ostrich 56: 236–262.A study of the longevity, species diversity, weight, diurnal activity, moult and breeding of forest birds in western Kenya was undertaken between January 1973 and January 1975. Some results from earlier and later studies are used where relevant. By mist-netting, 964 birds of 66 species were captured. The greatest longevity recorded to date is 19 years 6 months for a Cameroon Sombre Bulbul, Andropadus curvirostcis. Species diversity for different months, and the same month in different years are compared, along with those for different forests, and for non-forest habitats. Weight changes are recorded. Contrary to expectation, more birds were heavier, not lighter, when in moult. A bimodal rhythm of diurnal activity is recorded. The approximate duration of primary moult for 94 individuals of 28 species ranged from 37 to 350 days. The months of egg-laying are given for 64 species. A brief discussion on moulting and breeding cycles is included.
A list and classification of forest birds in Kenya
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Vande Weghe (no date) Les oiseaux de laforet de Nyungwe Ecological and biogeographical aspects of forest
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