A study of composition and diversity variation of avifauna along with different types of agroforestry system in Kibet town, Southern Ethiopia

Background Agroforestry is an integrated land-use system that plays a great role in the conservation of landscape biodiversity. The study aimed to assess the composition and diversity of avian species along with different habitat types of agroforestry in Kibet Town, Southern Ethiopia. Methods Four habitat types of agroforestry system which are home gardens, live fences, parkland, and eucalyptus woodlot were identified. Line transects were used for bird surveys. The Shannon diversity index (H′) and species evenness index (E) were used to compare diversity among habitat types. A similarity percentages (SIMPER) test was carried out to identify the main species and feeding guild that typified each habitat type. The overall significance was assessed with the ANOSIM test using PAST (version 4.03). Results A total of 50 bird species belonging to 28 families and 10 orders were recorded. Order Passeriformes (67.3%) had the highest number of species. Bird community composition differed among habitat types. The dissimilarity was mainly due to White-browed robin-chat (Cossypha heuglini), Streaky seed-eater (Serinus striolatus), Village Weaver (Ploceus cucullatus), African Paradise-Flycatcher (Terpsiphone viridis), and Black-Headed Paradise Flycatcher (T. rufiventer). The finding also revealed that insectivore was the dominant feeding guild. Conclusions The present study shows evidence that more insectivore bird species use different types of agroforestry as habitat and foraging sites. So, any concerned bodies who have engaged in avian conservation should give special consideration to this modified landscape.

Population density and structure of a breeding bird community in a suburban habitat in the Cuvelai drainage system, northern Namibia

In a suburb (c. 100 ha) of Ongwediva, a total of 30 breeding bird species were recorded in 2018. Shannon’s Diversity Index was 2.01. Passer domesticus comprised almost half of all breeding pairs (36.4 pairs / 10 ha). Granivores were by far the most numerous feeding guild, comprising 77.5 % of all birds breeding. Birds nesting on/in buildings were represented by two species only, but they comprised almost half (49.9 %) of all breeding birds. In comparison with other southern African towns, the number of bird species breeding in Ongwediva was low. This was compensated by high population densities of some species.

The frequency method in studying habitat preferences of common forest birds

This paper presents the results of a study on the habitat preferences of selected species of the bird community in the Morgi Forest, the Kolbuszowa Forest Division (SE Poland), with the use of the point-stand bird census method. The aim of the study was to test the effectiveness of the method in determining the frequency of colonisation of stands with different habitat parameters by the most abundant bird species. In 270 tree stands of a forest complex with diverse habitats, a bird census was carried out with four counts per each stand. Next, a list of the tree stands and the bird species recorded in the stands was compiled. The stands were divided into categories according to the forest habitat type, dominant species and age class. In the next step, the occurrence frequency of the most abundant bird species was calculated for each stand category. Among the analysed species, the majority showed a positive correlation between the frequency of occurrence and habitat fertility. The influence of the dominant stand species on the occurrence frequency of bird species was largely driven by habitat fertility. The lowest average frequency of the identified avian species was found in stands dominated by pine Pinus sylvestris, birch Betula sp. and black alder Alnus glutinosa. There was generally a positive relationship between age class and the bird community parameters. It is concluded that the point-stand method of bird census provides informative results for research on the habitat selectivity of bird populations.

Avian Use of Dairy Farm Ponds and Landowners’ Perceptions of Their Management for Wildlife Conservation

Farm ponds are among the last remaining lentic wetland habitats in human-dominated agricultural and suburban landscapes. However, their wildlife value and farmers’ willingness to maintain them for the conservation of regionally declining biodiversity are often both poorly documented. The objectives of this study of 61 dairy farm ponds located in Southern Quebec (Canada) were to (1) describe their biophysical features and birds’ use, (2) determine habitat and landscape characteristics that influence the bird community, and (3) assess the willingness of farmers to support wildlife use. The studied ponds were small (0.17 ha) and had rectangular shape with rocky/muddy steeply slopes (21°), surrounded by 3 m wide riparian strips and pastures, hayfields, and fallows. They were located about 300 m from farmhouses, buildings, streams, and adjacent ponds. A total of 1963 individuals belonging to 46 bird species were observed. The abundance of all bird species, of species with declining populations, and of crop damaging species were positively related to the area of fallow land and to the width of riparian strips; the areas of cereals and of mixed-wood forest had a negative influence. Only two habitat variables had influence on species richness: the width of riparian strips (+) and the distance to the closest farm buildings (–). Most pond landowners (>80%) were in favour of increasing wildlife use if they were given access to associated financial support and logistical assistance. Wider riparian strips and adjacent uncultivated field margins are recommended.

Mesoscale bird distribution pattern in montane phytophysiognomies along an ecotone between two hotspots

Brazil has a high diversity of birds and presents the largest number of threatened bird species in the neotropical region. Even so, there are gaps in the bird knowledge, especially in ecotonal montane regions. Given this panorama, this study aimed to analyse the bird community distribution (richness, composition, and beta diversity between phytophysiognomies) of an ecotonal montane landscape of southeastern Brazil, with the purpose of detecting substitution patterns of bird species on a meso-scale. Using bird data performed during the years 1998 to 2015 in 46 sampling points, we found high bird richness in montane phytophysiognomies along an ecotone between Cerrado and Atlantic Forest hotspots. The composition present species of both domains, with high turnover component. We highlight the field environments and candeais are considered homogeneous and threathened, which would directly affect birds. The present study contributes to future conservation strategies, as it demonstrates ecotonal regions as transition zones and reinforces the need to consider as particular ecological units. These ecotonal regions are key locations for understanding ecological patterns in response to environmental changes or phytophysiognomies. Knowing how partitioning of the composition occurs within an environmental mosaic is essential to understand the limits and distributions of the species and conserve them.

The Relative Importance of Human Disturbance, Environmental and Spatial Factors on the Community Composition of Wetland Birds

The present study investigates the relative importance of human disturbance, local environmental and spatial factors on variations in bird community composition in natural Ethiopian wetlands with high biodiversity conservation value. We quantified bird abundances, local environmental variables and human disturbances at 63 sites distributed over ten wetlands in two subsequent years. Variation partitioning analyses were used to explore the unique and shared contributions of human disturbance, local environmental variables and spatial factors on variations in community compositions of wetland bird species. Local environmental variables explained the largest amount of compositional variation of wetland bird species. Productivity-related variables were the most important local environmental variables determining bird community composition. Human disturbance was also an important determinant for wetland bird community composition and affected the investigated communities mainly indirectly through its effect on local environmental conditions. Spatial factors only played a minor role in variations in bird community composition. Our study highlights the urgent need for integrated management approaches that consider both nature conservation targets and socio-economic development of the region for the sustainable use and effective conservation of wetland resources.

Bird community monitoring at Wilson’s Creek National Battlefield, Missouri: Status report 2008–2020

Breeding bird surveys were initiated on Wilson’s Creek National Monument, Missouri, in 2008 to assess temporal changes in the species composition and abundance of birds on the park and to improve our understanding of relationships between breeding birds and their habitat and the effects of management actions, such as invasive plant species control and tree thinning, on bird populations. Birds were sampled using point counts with 38 variable circular plots located on a systematic grid of 400 x 400-m cells (originating from a random start point). All birds seen or heard on a plot during a 5-min sampling period were recorded. In the 13 years since initiating our breeding bird survey, birds were surveyed on as many of the 38 variable circular plots as possible each year, resulting in 444 cumulative plot visits. Surveys have yielded records for 119 different species of birds. Ninety-eight of the species recorded are classified as permanent or summer residents to the area, 18 are classified as transients in the area, and 3 as winter residents to the area. Eight breeding species recorded are considered species of conservation concern for the Central Hardwoods Bird Conservation Region, the bird conservation region in which Wilson’s Creek National Battlefield is located. Of the 98 breeding species recorded, 12 species in grassland habitat and 15 in woodland habitat occurred in numbers large enough to calculate annual abundances with some degree of confidence. Trends in abundance were classified as uncertain for most species, which means that no significant increases or decreases occurred but it is not certain that trends were <5% per year. The Indigo Bunting (Passerina cyanea) population in grassland habitat was stable. The Eastern Towhee (Pipilo erythrophthalmus) and Eastern Wood-pewee (Contopus virens) populations in woodland habitat were in moderate decline. Comparing population trends on the park with regional trends for the Central Hardwoods Bird Conservation Region suggests that the bird community at Wilson’s Creek National Battlefield is faring similarly to that of the region as a whole. Stable diversity, richness, and evenness values suggest that the park’s habitat has remained consistent in its ability to meet the requirements of many of the park’s breeding bird species. Any decline in species richness could reflect habitat management practices, but it could also reflect the influences of larger-scale factors such as weather or climatic conditions on vegetation. Therefore, continued monitoring of birds and their habitats on Wilson’s Creek National Battlefield as management and weather and climatic conditions change is essential for park management.

Bird community monitoring at George Washington Carver National Monu-ment, Missouri: Status report 2008–2020

Breeding bird surveys were initiated on George Washington Carver National Monument, Missouri, in 2008 to assess temporal changes in the species composition and abundance of birds on the park and to improve our understanding of relationships between breeding birds and their habitat and the effects of management actions, such as invasive plant species control and tree thinning, on bird populations. Birds were sampled using point counts with 70 variable circular plots located on a systematic grid of 100 x 100-m cells (originating from a random start point). All birds seen or heard on a plot during a 5-min sampling period were recorded. In the 13 years since initiating our breeding bird surveys on the park, birds were surveyed on as many of the 70 variable circular plots as possible each year, resulting in 520 cumulative plot visits. Surveys have yielded records for 100 different species of birds. Ninety-seven of the species recorded are classified as permanent or summer residents to the area, two are classified as transients in the area, and one as a winter resident to the area. Six breeding species recorded are considered species of conservation concern for the Central Hardwoods Bird Conservation Region, the bird conservation region in which George Washington Carver National Monument is located. Of the 97 breeding species recorded, ten species in grassland habitat and six in woodland habitat occurred in numbers large enough to calculate annual abundances with some degree of confidence. Trends in abundance were classified as uncertain for most species, which means that there were no significant increases or decreases, but it is not certain that trends were < 5% per year. The Northern Cardinal (Cardinalis cardinalis) in woodland habitat was stable. The Eastern Meadowlark (Sturnella magna) in grassland habitat was in moderate decline, and the Northern Bobwhite (Colinus virginianus) in grassland habitat was in steep decline. Comparing population trends (i.e., changes in population size over time) on the park with regional trends for the Central Hardwoods Bird Conservation Region suggests that the bird community at George Washington Carver National Monument is faring similarly to that of the region as a whole. Trends in the park’s popula-tions of Field Sparrow (Spizella pusilla) and Indigo Bunting (Passerina cyanea) in grassland habitat and Carolina Wren (Thryothorus ludovicianus) in woodland habitat were uncertain, whereas they declined significantly in the larger region, which could be a result of management on George Washington Carver National Monument. Red-bellied Woodpecker (Melanerpes carolinus) population trends, while uncertain in grassland habitat on the park, increased significantly in the region. The Red-bellied Woodpecker utilizes trees for foraging, which are sparse in the grassland habitat on the park. Declining diversity and richness values suggest that park habitat is declining in its ability to meet the requirements of many of the park’s breeding bird species. This decline in species richness could reflect habitat management practices, but it could also reflect the influences of larger-scale factors such as weather or climatic conditions on vegetation. Therefore, continued monitoring of birds and their habitats on George Washington Carver National Monument as management and weather and climatic conditions change is essential for park management.

Vocal Communication Within a Forest Bird Community

<p><b>This thesis takes a community approach to investigate the acoustics of forest birds in Zealandia sanctuary, Wellington. Initially, the annual changes in vocalisation output of 16 study species and their possible effect on bird conspicuousness were described. Environmental factors that may shape these avian vocalisations were addressed though invoking two key hypotheses, the acoustic adaptation hypothesis, and the acoustic niche hypothesis. In addition, the songs of selected species are investigated: the role of song harmonics in the native North Island saddleback, Philesturnus rufusater, and their role in ranging, change in song dialect through time and space in the introduced song thrush, Turdus philomelos, and temporal change in the song of the native grey warbler, Greygone igata. Vocal activity of the study species varied seasonally, affecting their detectability in bird counts. Some species were mostly first heard rather than seen and viceversa. The results lend support to the acoustic niche hypothesis in that vocalisations within the forest bird community appear to have evolved towards divergence, with native species’ vocalisations being more dispersed within the community acoustic space than those of the introduced species. However, all species concentrated their energy within relatively narrow frequency bands, supporting the predictions of the acoustic adaptation hypothesis. Adaptation to different transmission properties associated with different singing elevations or physiological parameters such as body weight may have an effect on shaping such bird vocalisations.</b></p> <p>Forests provide a complex acoustic space for sound transmission and a “sound window” may not be a constant property of a given forest. The study revealed that a prominent sound window persists in the lower frequency range that is less affected by habitat. Some high frequencies may have similar average attenuation values to those of low frequency, however, with greater fluctuation in attenuation. Ground effect is a further factor in determining how well different frequency ranges transmit and birds may use acoustic characteristics of their habitat to enhance their signal.</p> <p>Harmonics in North Island saddleback chatter song were found to play a potential role in ranging (estimating the distance of signaller), for playback songs with more relative energy within higher harmonics were evidently perceived as coming from a nearby individual.</p> <p>The repertoire size of the song thrush population studied in Zealandia has apparently evolved to become larger and more varied than the source population of song thrushes in the UK, with more syllables delivered with less repetition than the UK song recordings examined.</p> <p>Over a period of 7 years, syllables in grey warbler song have shifted to a higher frequency, but there was no difference in the temporal structure of the song. Habitat effect, competition on the acoustic signal from reintroduced birds and ambient noise level are considered as possible casual factors.</p>