Farmland as stopover habitat for migrating birds – effects of organic farming and landscape structure

Agricultural intensification in Europe has affected farmland bird populations negatively, both during summer and winter. Although the migratory period poses separate challenges on birds than breeding and wintering, the consequences of farming practices for birds during migration remain poorly investigated. We monitored abundance and species richness of migratory birds in autumn at matched pairs of organic and conventional farms situated either in intensively farmed open plains (homogeneous landscapes) or in small‐scale farming landscapes (heterogeneous landscapes) in southern Sweden. Total bird density did not differ between landscape types but was marginally higher on organic compared to conventional farms. When including taxonomic status in the model (passerines vs non‐passerines), we found significantly more birds on organic farms, and more non‐passerines in the homogeneous landscapes. The effect of farming practice and landscape type on density differed between functional groups. Omnivore density was higher in the homogeneous landscapes, and invertebrate feeders were marginally more abundant on organic farms. The effects of farming practice on the overall species richness and on the density of granivorous birds were landscape dependent. In the homogeneous landscapes, organic farms held a higher number of species and density of granivorous birds than conventional farms, but there was no such difference in the heterogeneous landscapes. Thus, organic farming can enhance abundance and species richness of farmland birds during migration, but the effect differs between landscape types and species. The effectiveness of organic farming was highest in the homogeneous landscape making it important to promote organic farming there. However, for some species during migration, increased heterogeneity in homogeneous landscapes may have negative effects. We propose that migratory bird diversity in homogeneous landscapes may be best preserved by keeping the landscape open, but that a reduced agricultural intensity, such as organic farming, should be encouraged.     

Impacts of organic and conventional dairy farmer attitude,behaviour and knowledge on farm biodiversity in Ireland

Agricultural intensification has caused significant declines in biodiversity. Agri-environmental schemes (AES), including organic farming, are thought to benefit biodiversity. However, under similar production conditions and in comparable locations and schemes, farms are not managed in the same way, with variable consequences for production and the environment. Understanding farmer attitude, behaviour and knowledge of the environment and their impacts on biodiversity may help us understand the variable impacts of AES on biodiversity. We combined a sociological survey of nine organic and eight conventional dairy farmers (measuring environmental and achievement attitudes; environmental and production-orientated behaviours and environmental knowledge), in Ireland, with a biodiversity (using plant richness as an indicator) assessment of their farms. We found higher plant richness on organic farms than conventional. Organic and conventional farmers had similar attitudes to farming achievement and the environment but organic farmers were better informed about environmental issues and carried out more environmentally orientated behaviours. Biodiversity was positively related to the amount of environmentally orientated behaviours and negatively related to production-orientated behaviours carried out on farms. Organic farmers who had more positive attitudes to the environment and were better informed about it had higher biodiversity on their farms compared to less positively inclined, less informed organic farmers. We show disparities between attitude and actual behaviour in relation to the environment, with organic farmers sharing similar attitudes to conventional farmers, but more prepared to inform themselves about and carry out environmentally friendly farming. Results indicate that organic farming and environmentally orientated behaviours benefit biodiversity and that there is an important link between farmer environmental attitudes and knowledge and the beneficial effects of organic farming on biodiversity. We encourage conservation orientated thinking and better environmental education among farmers, including those who already participate in an AES. This way, the benefits of the AES for the environment may be maximised.     

Nest success of Lapwings Vanellus vanellus on organic and conventional arable farms in the Netherlands

Increasing agricultural intensification has put farmland bird populations under great stress. Although organically managed farms tend to have higher densities of farmland birds than conventionally managed holdings, differences in crop management may also lead to differences in breeding success. With the use of agrochemicals prohibited on organic farms, weeds are controlled using mechanical methods that may pose a threat to ground-nesting birds. This study compares the territory densities and nesting success of the Lapwing Vanellus vanellus on organic and conventional arable farms in the Netherlands. Territory densities were generally higher on organic farms, although in one year nesting success was lower on organic than on conventional farms. This was caused by higher nest loss resulting from farming activities on organic farms. There were no differences in predation rates. The results of this study show that breeding Lapwings may face potential threats on organic farms. To sustain or enhance Lapwing populations on these farms, additional conservation measures should be implemented.     

Diet of nestling Barn Swallows <Emphasis Type="Italic">Hirundo rustica</Emphasis> in rural areas of Poland

Analysis of faecal sacs of nestling Barn Swallows Hirundo rustica from 52 breeding colonies located within fifteen spatially-separated villages in Poland has revealed that the basic component of the diet was Coleoptera (56.1% of all identified prey items), followed by Hymenoptera (24.1%), Diptera (16.1%) and Hemiptera (3.3%). The average mass of all prey items with known weight amounted to 3.40 mg (95% CL, 3.16–3.63 mg; median=0.49 mg) dry weight. Coleopterans associated with dung and manure jointly made up 23.5% of the number and 24.3% of the total biomass of all representatives of the order. Statistically significant negative relationships between the average weight of prey and number of prey found in 52 analyzed breeding sites suggest a particular need for Barn Swallows to find larger-bodied prey rather than to exploit the local abundance of smaller prey. The high percentage of Coleoptera in the diet of nestling Barn Swallows probably results from extensive or traditional farm management based on rules of organic farming in agricultural areas of central Europe, mainly commonly used organic fertilizers, and suggests the importance of these insects as a more easily accessible and larger-bodied prey in comparison to some small Diptera or Hymenoptera. We believe that a large number of randomly collected faecal samples from tens of breeding sites allow us to precisely describe variation in the diet of the Barn Swallow. Our work has great importance for documenting of the food composition of the Barn Swallow in traditional European countrysides, i.e. under environmental and agricultural conditions which, as a result of transformations of the system of farming, ceased to exist in the western and northern part of this continent.     

Consequences of organic farming and landscape heterogeneity for species richness and abundance of farmland birds

It has been suggested that organic farming may benefit farmland biodiversity more in landscapes that have lost a significant part of its former landscape heterogeneity. We tested this hypothesis by comparing bird species richness and abundance during the breeding season in organic and conventional farms, matched to eliminate all differences not directly linked to the farming practice, situated in either homogeneous plains with only a little semi-natural habitat or in heterogeneous farmland landscapes with abundant field borders and semi-natural grasslands. The effect of farm management on species richness interacted with landscape structure, such that there was a positive relationship between organic farming and diversity only in homogeneous landscapes. This pattern was mainly dependent on the species richness of passerine birds, in particular those that were invertebrate feeders. Species richness of non-passerines was positively related to organic farming independent of the landscape context. Bird abundance was positively related to landscape heterogeneity but not to farm management. This was mainly because the abundance of passerines, particularly invertebrate feeders, was positively related to landscape heterogeneity. We suggest that invertebrate feeders particularly benefit from organic farming because of improved foraging conditions through increased invertebrate abundances in otherwise depauperate homogeneous landscapes. Although many seed-eaters also benefit from increased insect abundance, they may also utilize crop seed resources in homogeneous landscapes and conventional farms. The occurrence of an interactive effect of organic farming and landscape heterogeneity on bird diversity will have consequences for the optimal allocation of resources to restore the diversity of farmland birds.     

Organic farming improves pollination success in strawberries

Pollination of insect pollinated crops has been found to be correlated to pollinator abundance and diversity. Since organic farming has the potential to mitigate negative effects of agricultural intensification on biodiversity, it may also benefit crop pollination, but direct evidence of this is scant. We evaluated the effect of organic farming on pollination of strawberry plants focusing on (1) if pollination success was higher on organic farms compared to conventional farms, and (2) if there was a time lag from conversion to organic farming until an effect was manifested. We found that pollination success and the proportion of fully pollinated berries were higher on organic compared to conventional farms and this difference was already evident 2-4 years after conversion to organic farming. Our results suggest that conversion to organic farming may rapidly increase pollination success and hence benefit the ecosystem service of crop pollination regarding both yield quantity and quality.     

The effectiveness of volunteer nest protection on the nest success of Northern Lapwings Vanellus vanellus on Dutch arable farms

Clutches of ground‐nesting farmland birds are often destroyed by farming operations, resulting in insufficient reproductive success and subsequently declining populations. The aim of this study was to investigate whether volunteer nest protection can enhance nest success of ground‐nesting birds. The study compared nest success of protected and unprotected Northern Lapwing Vanellus vanellus nests over 2 years on arable farms in the Netherlands. Because of different crop management, nest success of ground‐breeding birds might differ between organic and conventional arable farms. The effectiveness of volunteer nest protection was therefore investigated on both farm types. Although nest protection significantly reduced nest loss due to farming operations, there were no significant differences in total clutch survival of protected and unprotected nests. However, sample sizes of unprotected nests, and protected nests on organic farms, were relatively small, which may have reduced statistical power. There were indications that protected nests were predated or deserted more often. We recommend exploring different ways to improve the effectiveness of volunteer nest protection through a further reduction of nest loss due to farming operations and predation.     

大杜鹃对家燕的巢寄生

了解杜鹃(Cuculus spp.)对不同宿主鸟类的巢寄生,是研究杜鹃与其宿主之间协同进化的重要基础资料。大杜鹃(Cuculus canorus)和家燕(Hirundo rustica)分布遍及全国,且为同域分布,但两者之间的寄生现象尚未有过系统调查。2012年和2014年4~8月,对繁殖于吉林市昌邑区桦皮厂镇(34°58′44.18″N,126°13′26.83″E,海拔184 m)和海南岛的家燕种群进行调查,结果表明,吉林市昌邑区桦皮厂镇家燕种群的寄生率为2.4%(1/42),而在海南岛所调查的1 719个家燕巢未发现杜鹃寄生现象。同时在网络上搜集家燕巢寄生的报道案例,共记录到13巢家燕被大杜鹃寄生繁殖,均发生在北方的家燕种群。     

National and regional patterns of habitat association with foraging Barn Swallows Hirundo rustica in the UK

Capsule Barn Swallows showed a consistent association with cattle across the UK, but certain landscape features, particularly mixed field types and tall trees, were also important.

Aim To provide nationally representative data on habitat selection in foraging Barn Swallows.

Method Observers carried out four timed point counts within an allocated 2-km square(s). Point counts were at least 500 m apart and considered as independent sample points. Each point count covered 100 m radius and was visited twice during the summer. An index of foraging activity was derived from the number of foraging passes made by Barn Swallows within ten minutes. The maximum count of Swallows present was also recorded. Habitat data included the presence or absence of landscape features and buildings and the proportion of area covered by particular crop and boundary types within the 100 m count radius.

Results Cattle were the single most important and most consistent variable associated with foraging Barn Swallows, in every UK region. Horses were also important in the southeast. Grassland was only important if livestock were present. Foraging pass rates were higher where count circles contained a mixture of grass and arable fields rather than just one or the other. There was a general positive relationship between foraging pass rates and the presence of tall trees in boundaries, and this was significant in the arable eastern region of the UK, where their relative importance of concentrating prey may be more acute.

Conclusion Historical changes in the distribution and availability of habitat features associated with foraging Barn Swallows are consistent with regional differences in population change for this species in the UK. These patterns of association are discussed in terms of changes in land use, the widespread loss of mixed farming and simplifications to landscape complexity.     

Measuring farmers' attitude towards breeding tools: the Livestock Breeding Attitude Scale

Under-use of genetic improvement tools and low participation in breeding programmes are key drivers of breeding programmes under-performance. Both aspects are heavily influenced by farmers attitudes which, to date, have not been analysed in an objective and systematic manner. A key factor constraining the implementation of attitudinal studies towards livestock breeding tools is the lack of a reference scale for measuring attitudes. In this research, we provide the livestock breeding sector with such a reference measure. We developed the scale following the standardized psychometric methodologies and statistical tools. Then, as a case study, we used the scale to explore the attitudes of beef and dairy sheep farmers in Australia, New Zealand and Spain and analysed farmer and farming system factors related to those attitudes. Fourteen sheep and beef breed associations facilitated the implementation of a survey of 547 farmers, generating data that was used for the scale evaluation. The relationship between attitudinal factors and farmer and farming system factors was analysed using generalized linear models across and within breeds. The results suggest that the 8-item definitive scale we have developed is appropriate to measure farmer attitudes. We found that attitudes towards genetic improvement tools have two components; i) traditional selection and ii) genetic and genomic selection combined. This means that positive attitudes towards traditional phenotypic selection do not necessarily imply a negative attitude towards genetic and genomic selection tools. Farmer attitudes varied greatly not only across the studied breeds, species and countries, but also within them. High-educated farmers of business-oriented farms tend to have the most negative attitude towards traditional selection. However, attitudes towards genetic and genomic selection tools could not be linked to these factors. Finally, we found that the breed raised had a large effect on farmer attitude. These findings may help in the evolution of breeding programmes by identifying both the farmers most inclined to uptake breeding innovations in the early stages of its establishment and the farmers who would be more reluctant to participate in such programmes, thus informing where to focus extension efforts.     

Does organic farming benefit farmland birds in winter?

The generally higher biodiversity on organic farms may be influenced by management features such as no synthetic pesticide and fertilizer inputs and/or by differences in uncropped habitat at the site and landscape scale. We analysed bird and habitat data collected on 48 paired organic and conventional farms over two winters to determine the extent to which broad-scale habitat differences between systems could explain overall differences in farmland bird abundance. Density was significantly higher on organic farms for six out of 16 species, and none on conventional. Total abundance of all species combined was higher on organic farms in both years. Analyses using an information-theoretic approach suggested that both habitat extent and farm type were important predictors only for starling and greenfinch. Organic farming as currently practised may not provide significant benefits to those bird species that are limited by winter food resources, in particular, several declining granivores.     

Mammals,agri‐environment schemes and set‐aside – what are the putative benefits?

• 1 The impacts of agricultural intensification on farmland wildlife have been the subject of increasing concern, particularly over the last two decades. Population declines have occurred for a number of mammalian species, sometimes drastically so, and changes in farming practice are believed to be significant contributory factors.
• 2 The major policy instruments for delivering environmental benefits on farmland are agri‐environment schemes. These encourage farmers to adopt more environmentally sensitive farming practices to promote farmland biodiversity. Additionally, compulsory set‐aside, which reduces agricultural surplus, could also have positive impacts on wildlife. In this paper we consider some of the putative benefits of agri‐environment schemes and set‐aside for mammals.
• 3 We review how establishment and management options within agri‐environment schemes and set‐aside might affect habitat resources for mammals. For example, conservation headlands increase plant and invertebrate resources within the crop edge for mammals such as wood mice. Grassy field margins can support communities of smaller mammals, and hedgerows may act as important commuting and hunting routes. Their potential will depend on factors such as seed mixtures used, timing and severity of cutting, and length of time they have been in place.
• 4 At a farm level, habitat heterogeneity may be increased through organic agriculture, which is supported by some agri‐environment schemes. Studies suggest significant benefits to mammals, including wood mice and bats. However, it is increasingly recognized that effective conservation of farmland mammals must seek solutions at the landscape scale, addressing such issues as habitat connectivity between farms. One approach may be the better targeting of scheme agreements.
• 5 We suggest that agri‐environment schemes and set‐aside can contribute to the conservation of mammals on farmland. Recent policy changes are likely to have further positive impacts on farmland wildlife but appropriate mammal monitoring programmes must be developed rigorously to assess their effects.

     

Using molecular and crowd-sourcing methods to assess breeding ground diet of a migratory brood parasite of conservation concern

Breeding ground food availability is critical to the survival and productivity of adult birds. The common cuckoo Cuculus canorus is a brood-parasitic Afro-Palearctic migrant bird exhibiting long-term (breeding) population declines in many European countries. Variation in population trend between regions and habitats suggests breeding ground drivers such as adult food supply. However, cuckoo diet has not been studied in detail since before the most significant population declines in Europe began in the mid-1980s. 20th century studies of cuckoo diet largely comprised field observations likely to carry bias towards larger prey taxa. Here we demonstrate the potential value of 1) using high-throughput DNA sequencing of invertebrate prey in faeces to determine cuckoo diet with minimal bias towards large prey taxa, and 2) using crowd-sourced digital photographs from across Britain to identify lepidopteran cuckoo prey taxa during recent years post-decline (2005–2016). DNA analysis found a high frequency of Lepidoptera, including moths of family Lasiocampidae, prominent within the past literature, but also grasshoppers (Orthoptera) and flies (Diptera) that may be overlooked by field observation methodologies. The range of larval lepidopteran prey identified from photographs largely agreed with those previously documented, with potential signs of reduced diversity, and identities of key adult prey taxa were supported by molecular results. Notably, many identified cuckoo prey taxa have shown severe declines due to agricultural intensification, suggesting this has driven spatial patterns of cuckoo loss. Landscape-scale, lowland rewilding interventions provide opportunities to understand the scale of reversal of previous agricultural intensification that may be necessary to restore prey populations sufficiently to permit recolonization by cuckoos.     

Large-scale land use change may explain bird species declines in semi-natural areas: the case of Black Grouse population collapse in Lower Saxony, Germany

Farmland birds in Central Europe have been heavily declining in past decades. Among them are many ground-nesting species, adapted to semi-natural but secondary habitats. A vivid example is the Black Grouse (Tetrao tetrix) in the lowlands of north-western Germany, the Netherlands and Denmark, where the species′ populations experienced dramatic declines between the 1950s and 1970s. One explanation for these ubiquitous population declines might be large-scale changes in agricultural land use and land cover. We investigated several agricultural indices at three hierarchic administrative scales in parts of the federal state Lower Saxony, Germany, and related changes in these indicators with the Black Grouse declines. Land cover proportions remained relatively stable whereas indices of agricultural intensification heavily increased from 1952 to 1973. Multiple regression showed that change in farmland area was the best predictor of the trends across scales. Correlates of Black Grouse abundance were moor at the medium scale and pasture cover and fallow land at the smallest scale. Our results support the hypothesis that Black Grouse population dynamics in the lowlands of Central Europe were affected by land use changes. They show that Black Grouse populations in Central Europe were dependent upon extensive farming and may provide additional explanation where underlying factors on the habitat scale cannot fully explain the declines.     

Farmers’ perceptions of biodiversity and their willingness to enhance it through agri-environment schemes: A comparative study from Estonia and Finland

This comparative study is based on structured interviews with farmers participating in the agri-environment schemes in Estonia and Finland. It explores farmers’ interest in and knowledge of farmland wildlife, their understanding of the concept of biodiversity, and awareness of the potential causes behind declines of farmland birds. It also examines the relationship between farmers’ interest and willingness to undertake practices favouring farmland wildlife. Estonian and Finnish farmers showed considerable interest in wildlife on their farms, which was only weakly related to the self-assessed knowledge of wildlife. Many farmers viewed biodiversity from a narrow perspective often excluding species directly related to farming. Finnish farmers expressed more concern about the decline in common farmland species than Estonian ones. In both countries farmers rated intensification of agriculture as the major driving force behind farmland bird declines. The expressed interest in wildlife positively correlated with willingness to undertake wildlife-friendly measures. Only farmers with agri-environment contracts targeted specifically at biodiversity enhancement were more knowledgeable about practical on-farm activities favouring wildlife, and were more willing to employ them than the rest. Estonian farmers expressed a high degree of willingness to enhance wildlife though agri-environment management, which is a good sign for better implementation of the recently established national programme towards conservation.     

Benefits of organic farming to biodiversity vary among taxa

Habitat and biodiversity differences between matched pairs of organic and non-organic farms containing cereal crops in lowland England were assessed by a large-scale study of plants, invertebrates, birds and bats. Habitat extent, composition and management on organic farms was likely to favour higher levels of biodiversity and indeed organic farms tended to support higher numbers of species and overall abundance across most taxa. However, the magnitude of the response varied; plants showed larger and more consistent responses than other taxa. Variation in response across taxa may be partly a consequence of the small size and isolated context of many organic farms. Extension of organic farming could contribute to the restoration of biodiversity in agricultural landscapes.     

Mate guarding in the Linnet Carduelis cannabina

Capsule?House Sparrow (Passer domesticus) populations in south Swedish farmland are not affected by supplemental winter feeding, irrespective of agricultural landscape type or presence of animal husbandry, although winter populations declined more in mixed farmland and when farms contained animal husbandry.

Aims?To investigate whether food limitation of House Sparrow population size during the winter varied spatially in relation to agricultural landscape intensification and farm management.

Methods?We experimentally increased the winter food supply for populations on farmsteads in replicated landscapes that differed in agricultural intensification (open plains versus mixed farming) and/or farm management (crop farming versus animal husbandry), and estimated possible differences in effects on winter population change.

Results?We found no effect of supplementary winter feeding on changes in House Sparrow population sizes over the winter, irrespective of agricultural landscape type or presence of animal husbandry at the farm. However, we found a significantly larger winter population decline in mixed farmland and when farms contained animal husbandry.

Conclusions?The results suggest that House Sparrow populations in south Swedish farmland are not primarily limited by winter food availability. Alternatively, supplemental winter feeding may augment interspecific competition or attracts predators, offsetting any positive effect on population change. However, the stronger population decline in landscapes in which more breeding resources may be available (animal husbandry farms, mixed farmland), suggests stronger intraspecific competition during the winter in line with the resource separation hypothesis.     

Maize‐field complexity and farming system influence insectivorous birds’ contribution to arthropod herbivore regulation

The contribution of insectivorous birds to reducing crop damage through suppression of herbivory remains underappreciated, despite their role as cropland arthropod predators. We examined the roles of farming system, crop cover pattern, and structural configuration in influencing assemblage composition of insectivorous birds and their herbivorous arthropod prey across maize fields, and determined how bird exclusion affects crop herbivory levels. To achieve these objectives, we collected data across a sample of organic and conventional small‐scale non‐Bt maize farms in western Kenya. Assessments of abundance, diversity, and richness of insectivorous birds and abundance of their arthropod prey were compared between organic and conventional small‐scale non‐Bt maize on monocultured and inter‐cropped farms. We also employed bird exclusion experiments to assess impacts of bird predation on herbivorous arthropod abundance. Results showed that higher structural heterogeneity supported higher insectivorous bird richness, particularly under organic systems, dense trees, large woodlots, and thick hedgerows. Bird abundance further increased with crop diversity but not in relation to cropping method, hedgerow type, or percent maize cover per se. Conversely, herbivorous arthropod abundance and richness increased on conventional farms and those with higher percent maize cover, but were unaffected by cropping methods, tree, or hedgerow characteristics. Birds’ arthropod prey was more abundant under completely closed experimental plots compared with open or semi‐closed plots, confirming a significant linkage between birds and herbivorous arthropod suppression. In this study, we demonstrate importance of structural heterogeneity in agricultural landscapes, including diverse croplands and on‐farm trees to maximize insectivorous birds’ contribution to reducing crop arthropod herbivory. Abstract in Swahili is available with online material.     

Partitioning the effects of livestock farming on the diet of an aerial insectivorous passerine,the Barn Swallow Hirundo rustica

Capsule The presence of farm animals increases the amount of larger insect prey (mainly large Diptera and Coleoptera) and decreases the proportion of smaller prey (Hymenoptera).

Aims To determine the relationships between presence of farm animals and diversity of diet of nestling Barn Swallows from 52 colonies located at sites with and without livestock.

Methods Diet was determined on the basis of faecal analysis. We used two approaches to quantify livestock based on their spatial distribution – a breeding site-focused approach and a village-focused approach.

Results Our results show a relationship between the presence of livestock and the size, number and composition of insect prey detected in the diet of nestling Barn Swallows. The results from the two approaches we used in our study were broadly consistent, although effects varied according to the number and types of animal being raised. The presence of domestic animals increases the amount of larger prey (mainly larger Diptera and Coleoptera) and decreases the proportion of smaller prey (Hymenoptera species). The effect of individual livestock species, mainly pigs and poultry alone, was considerably higher than the effects of pooling livestock species from Principal Component Analysis.

Conclusion Our results imply that Barn Swallows were foraging beyond the immediate area of the farm buildings in which they nest, suggest considerable adaptability in the species' diet and further emphasize the ecological role that livestock play in providing a source of prey of a required size rather specific identity. Furthermore, a statistically significant positive effect of average mass of prey (which is a direct consequence of the presence of cattle at a breeding site) on colony size suggests that livestock farming provides a more profitable prey community, which may ultimately increase local populations of Barn Swallow.     

Impacts of Agriculture on the Diet and Productivity of Mackinder's Eagle Owls (Bubo capensis mackinderi ) in Kenya

Land conversion for agriculture is an increasing threat to biodiversity conservation, but its ecological effects on African birds is practically unknown. We investigated the impacts of agriculture on the diet and productivity of a small, disjunct population of Mackinder's eagle owls ( Bubo capensis mackinderi  ) in central Kenya. Owl diet was determined by analysis of pellets and other remains and compared to small mammal populations estimated by live trapping in two habitats. Small mammal abundance was low and averaged 7.4 small mammals/ha in farms and 0.5 small mammals/ha in grassland. Owls consumed a wide diversity of prey. The majority were mammals (87%) followed by birds (7%) and insects (5%). The percentage of small mammals in owl diet correlated positively with the relative abundance of small mammals during monthly trapping sessions. Diet composition did not influence owl breeding success. Farming activities affected owl diet composition through crop production. The amount of maize, peas, and carrots growing in farms was correlated with the abundance of Mastomys sp. and Procavia sp. in the owl's diet. Agricultural activities had a large effect on Mackinder's eagle owl diet by increasing the abundance of certain small-mammal prey and attracting owl prey to farms, though farming practices harmful to owls were observed.