Showing papers by "Royal Society for the Protection of Birds published in 2005"

Farming and the Fate of Wild Nature

Abstract: World food demand is expected to more than double by 2050. Decisions about how to meet this challenge will have profound effects on wild species and habitats. We show that farming is already the greatest extinction threat to birds (the best known taxon), and its adverse impacts look set to increase, especially in developing countries. Two competing solutions have been proposed: wildlife-friendly farming (which boosts densities of wild populations on farmland but may decrease agricultural yields) and land sparing (which minimizes demand for farmland by increasing yield). We present a model that identifies how to resolve the trade-off between these approaches. This shows that the best type of farming for species persistence depends on the demand for agricultural products and on how the population densities of different species on farmland change with agricultural yield. Empirical data on such density-yield functions are sparse, but evidence from a range of taxa in developing countries suggests that high-yield farming may allow more species to persist.

Developing indicators for European birds

Abstract: The global pledge to deliver ‘a significant reduction in the current rate of biodiversity loss by 2010’ is echoed in a number of regional and national level targets. There is broad consensus, however, that in the absence of conservation action, biodiversity will continue to be lost at a rate unprecedented in the recent era. Remarkably, we lack a basic system to measure progress towards these targets and, in particular, we lack standard measures of biodiversity and procedures to construct and assess summary statistics. Here, we develop a simple classification of biodiversity indicators to assist their development and clarify purpose. We use European birds, as example taxa, to show how robust indicators can be constructed and how they can be interpreted. We have developed statistical methods to calculate supranational, multi-species indices using population data from national annual breeding bird surveys in Europe. Skilled volunteers using standardized field methods undertake data collection where methods and survey designs differ slightly across countries. Survey plots tend to be widely distributed at a national level, covering many bird species and habitats with reasonable representation. National species' indices are calculated using log-linear regression, which allows for plot turnover. Supranational species' indices are constructed by combining the national species' indices weighted by national population sizes of each species. Supranational, multi-species indicators are calculated by averaging the resulting indices. We show that common farmland birds in Europe have declined steeply over the last two decades, whereas woodland birds have not. Evidence elsewhere shows that the main driver of farmland bird declines is increased agricultural intensification. We argue that the farmland bird indicator is a useful surrogate for trends in other elements of biodiversity in this habitat.

The Convention on Biological Diversity's 2010 target

Abstract: Governments are often accused of responding only to short-term and parochial considerations. It is therefore remarkable that representatives of 190 countries recently committed themselves at the Convention on Biological Diversity to reducing biodiversity loss. This presents conservation biologists with perhaps their greatest challenge of the decade. The authors of this Policy Forum describe approaches to identifying more of the earth9s biological diversity; understanding how biological, geophysical, and geochemical processes interact; and presenting scientific knowledge in time to contribute to and achieve the 2010 target.

Monitoring change in biodiversity through composite indices

Abstract: The need to monitor trends in biodiversity raises many technical issues. What are the features of a good biodiversity index? How should trends in abundance of individual species be estimated? How should composite indices, possibly spanning very diverse taxa, be formed? At what spatial scale should composite indices be applied? How might change-points—points at which the underlying trend changes—be identified? We address some of the technical issues underlying composite indices, including survey design, weighting of the constituent indices, identification of change-points and estimation of spatially varying time trends. We suggest some criteria that biodiversity measures for use in monitoring surveys should satisfy, and we discuss the problems of implementing rigorous methods. We illustrate the properties of different composite indices using UK farmland bird data. We conclude that no single index can capture all aspects of biodiversity change, but that a modified Shannon index and the geometric mean of relative abundance have useful properties.

Sparing land for nature: exploring the potential impact of changes in agricultural yield on the area needed for crop production

Abstract: How can rapidly growing food demands be met with least adverse impact on nature? Two very different sorts of suggestions predominate in the literature: wildlife-friendly farming, whereby on-farm practices are made as benign to wildlife as possible (at the potential cost of decreasing yields); and land-sparing, in which farm yields are increased and pressure to convert land for agriculture thereby reduced (at the potential cost of decreasing wildlife populations on farmland). This paper is about one important aspect of the land-sparing idea – the sensitivity of future requirements for cropland to plausible variation in yield increases, relative to other variables. Focusing on the 23 most energetically important food crops, we use data from the Food and Agriculture Organisation (FAO) and the United Nations Population Division (UNPD) to project plausible values for 2050 for population size, diet, yield, and trade, and then look at their effect on the area needed to meet demand for the 23 crops, for the developing and developed worlds in turn. Our calculations suggest that across developing countries, the area under those crops will need to increase very considerably by 2050 (by 23% under intermediate projections), and that plausible variation in average yield has as much bearing on the extent of that expansion as does variation in population size or per capita consumption; future cropland area varies far less under foreseeable variation in the net import of food from the rest of the world. By contrast, cropland area in developed countries is likely to decrease slightly by 2050 (by 4% under intermediate projections for those 23 crops), and will be less sensitive to variation in population growth, diet, yield, or trade. Other contentious aspects of the land-sparing idea require further scrutiny, but these results confirm its potential significance and suggest that conservationists should be as concerned about future agricultural yields as they are about population growth and rising per capita consumption.

The 2010 challenge: data availability, information needs and extraterrestrial insights.

Abstract: At the 2002 Johannesburg World Summit on Sustainable Development, 190 countries endorsed a commitment to achieve, by 2010, a significant reduction of the current rate of biodiversity loss at the global, regional and national levels. A wide range of approaches is available to the monitoring of progress towards this objective. The strengths and weaknesses of many of these approaches are considered, with special attention being given to the proposed and existing indicators described in the other papers in this issue. Recommendations are made about the development of indicators. Most existing and proposed indicators use data collected for other purposes, which may be unrepresentative. In the short term, much remains to be done in expanding the databases and improving the statistical techniques that underpin these indicators to minimize potential biases. In the longer term, indicators based on unrepresentative data should be replaced with equivalents based on carefully designed sampling programmes. Many proposed and existing indicators do not connect clearly with human welfare and they are unlikely to engage the interest of governments, businesses and the public until they do so. The extent to which the indicators already proposed by parties to the Convention on Biological Diversity are sufficient is explored by reference to the advice an imaginary scientific consultant from another planet might give. This exercise reveals that the range of taxa and biomes covered by existing indicators is incomplete compared with the knowledge we need to protect our interests. More fundamentally, our understanding of the mechanisms linking together the status of biodiversity, Earth system processes, human decisions and actions, and ecosystem services impacting human welfare is still too crude to allow us to infer reliably that actions taken to conserve biodiversity and protect ecosystem services are well chosen and effectively implemented. The involvement of social and Earth system scientists, as well as biologists, in collaborative research programmes to build and parameterize models of the Earth system to elucidate these mechanisms is a high priority.

Habitat selection by yellowhammers Emberiza citrinella on lowland farmland at two spatial scales: implications for conservation management

Abstract: Summary 1. Yellowhammer Emberiza citrinella populations have declined rapidly in the UK over recent decades, and a clear understanding of their habitat requirements is important to help inform conservation schemes. We aimed to disentangle and rank the effects of winter versus breeding season habitat characteristics. 2. We used information theoretic methods to analyse the factors determining yellowhammer distribution across 26 sites in England and Wales. We did this at two spatial levels: individual field boundaries and individual territories, the latter consisting of spatial clusters of boundaries. 3. We considered the role of nine predictor variables, all of which have been suggested in the literature as potentially important. These comprised boundary height and width, and the presence of hedges, trees, ditches, boundary strips, tillage crops, winter set-aside and winter stubbles. 4. The results of the statistical modelling showed that winter habitats play an important role in determining where birds locate territories in summer. In particular, the presence of rotational set-aside fields in winter showed the strongest association with summer territories. 5. There were minor differences between the territory- and boundary-based models. Most notably, the territory data demonstrated a strong preference for territories containing trees, but this was not observed in the boundary data set. We suggest that the differences between the models may reflect different scales of habitat selection. Boundary occupancy reflects broad distributions of habitat suitability; territory occupancy patterns better reveal detailed habitat requirements. 6. Regional densities were more closely correlated with the predictions of the boundarybased model than those of the territory-based model, and we discuss the implications of this for interpreting habitat association models. 7. Synthesis and applications. Provision of winter set-aside fields for summer territory selection by yellowhammers is an important consideration for farm management where conservation is a priority. We show that models based on occupancy of individual boundary units (e.g. hedgerows) correlate with the density of territories at the farm scale; thus farm management practices link directly to population sizes through effects on the quality of breeding habitat.

The management of crop structure: a general approach to reversing the impacts of agricultural intensification on birds?

Abstract: Agricultural intensification is accepted widely as a cause of bird population declines on farmland in Europe and North America. Although intensification is multivariate, one common theme is the impact on variation in crop structure, both within and between fields. Intensification creates simpler, more homogeneous and denser swards in both tillage crops and grassland. This influences predation risk, exposure to weather extremes and the diversity, abundance and accessibility of food. Birds trade off these pressures in different ways, so that the more uniform and dense the vegetation, the fewer the number of birds and range of species that are able to nest and forage successfully. Reversing recent trends towards dense, simplified and homogeneous swards will improve nesting and foraging habitat conditions for a wide range of species across farming systems, and may represent a cost-effective mechanism for the further improvement of agri-environment scheme options designed to assist the recovery of farmland bird populations.

Modelling relationships between birds and vegetation structure using airborne LiDAR data: a review with case studies from agricultural and woodland environments

Abstract: Airborne LiDAR (Light Detection and Ranging) is a remote sensing technology that offers the ability to collect high horizontal sampling densities of high vertical resolution vegetation height data, over larger spatial extents than could be obtained by field survey. The influence of vegetation structure on the bird is a key mechanism underlying bird–habitat models. However, manual survey of vegetation structure becomes prohibitive in terms of time and cost if sampling needs to be of sufficient density to incorporate fine-grained heterogeneity at a landscape extent. We show that LiDAR data can help bridge the gap between grain and extent in organism–habitat models. Two examples are provided of bird–habitat models that use structural habitat information derived from airborne LiDAR data. First, it is shown that data on crop and field boundary height can be derived from LiDAR data, and so have the potential to predict the distribution of breeding Sky Larks in a farmed landscape. Secondly, LiDAR-retrieved canopy height and structural data are used to predict the breeding success of Great Tits and Blue Tits in broad-leaved woodland. LiDAR thus offers great potential for parameterizing predictive bird–habitat association models. This could be enhanced by the combination of LiDAR data with multispectral remote sensing data, which enables a wider range of habitat information to be derived, including both structural and compositional characteristics.

A Framework for Improved Monitoring of Biodiversity: Responses to the World Summit on Sustainable Development

Abstract: The Convention on Biological Diversity (CBD) and the World Summit on Sustainable Development (WSSD) endorsed the Hague Ministerial Declaration that calls for a significant reduction of the current rate of biodiversity loss at the global, regional, and national levels by 2010. We argue that there is a shortage of standardized, regularly repeated measurements of the state of biomes and their biota that could be used to monitor progress toward this goal. In particular, there are few data that directly or indirectly measure the delivery of ecosystem services that depend on biodiversity. Given the link made in the declaration between biodiversity and poverty alleviation, this deficiency is of special concern. We suggest that greater attention should be given to defining the questions about changes in biodiversity that are relevant to CBD and WSSD goals and propose a framework through which the links between these questions and programs of monitoring and research could be made stronger and more explicit. The framework consists of three stages. First is a scoping stage in which reviews of existing knowledge and interactions with stakeholders help to define the subject of the evaluation and lead to a preliminary model of the system of interest. Second is a design stage in which the types of measurement and sampling strategies are selected by evaluating their fitness for purpose and the resources available to conduct the work. The final stage is implementation and reporting, which considers data collection and storage and the evaluation and dissemination of results. This framework can be applied across a broad range of biodiversity attributes and scales and, if combined with a systematic review of the most important and relevant questions about changes in biodiversity, would improve the coverage, fitness for purpose, and value for money of biodiversity monitoring. Slowing the rate of loss of biodiversity requires conservation action, but to know where this is most needed and whether it is working requires better and more comprehensive monitoring.

Warmer springs advance the breeding phenology of golden plovers Pluvialis apricaria and their prey (Tipulidae)

Abstract: Most studies of climate-driven changes in avian breeding phenology have focused on temperate passerines, yet the consequences of such environmental change may be more deleterious for other avian taxa, such as arctic and sub-arctic waders (Charadrii). We therefore examine large-scale climatic correlates of the breeding phenology of one such species (golden plover Pluvialis apricaria), and the timing of emergence of their adult tipulid prey, to assess the potential for climate change to disrupt breeding performance. Golden plover first-laying dates were negatively correlated with both March and April temperature, the mean laying date of first clutches was additionally negatively correlated with March rainfall. The timing of final laying dates were negatively correlated with April temperature only. The timing of tipulid emergence was negatively correlated with May temperature. In combination with historical climatic data, these models suggest a 9-day advancement of golden plover first-laying dates occurred during the 1990s, although this remains within the range of natural variation for the twentieth century. The magnitudes of predicted changes in mean and final laying dates, and the timing of tipulid emergence, were smaller. Climate predictions for 2070–2099 suggest potential advances in first-laying dates by 25 days, whilst the timings of mean and final laying dates are predicted to change by 18 days and 13 days, and tipulid emergence by 12 days. Given the importance of adult tipulids to young golden plover chicks, these changes may result in a mismatch between the timing of first-laying dates and tipulid emergence, so reducing the success of early breeding attempts. Modelling suggests that these changes could reduce breeding success in a South Pennines population by about 11%.

Investigating the relationships between the distribution of British ground beetle species (Coleoptera, Carabidae) and temperature, precipitation and altitude

Abstract: Aims We examine the relationships between the distribution of British ground beetle species and climatic and altitude variables with a view to developing models for evaluating the impact of climate change. Location Data from 1684 10-km squares in Britain were used to model species–climate/altitude relationships. A validation data set was composed of data from 326 British 10-km squares not used in the model data set. Methods The relationships between incidence and climate and altitude variables for 137 ground beetle species were investigated using logistic regression. The models produced were subjected to a validation exercise using the Kappa statistic with a second data set of 30 species. Distribution patterns for four species were predicted for Britain using the regression equations generated. Results As many as 136 ground beetle species showed significant relationships with one or more of the altitude and climatic variables but the amount of variation explained by the models was generally poor. Models explaining 20% or more of the variation in species incidence were generated for only 10 species. Mean summer temperature and mean annual temperature were the best predictors for eight and six of these 10 species respectively. Few models based on altitude, annual precipitation and mean winter temperature were good predictors of ground beetle species distribution. The results of the validation exercise were mixed, with models for four species showing good or moderate fits whilst the remainder were poor. Main conclusions Whilst there were many significant relationships between British ground beetle species distributions and altitude and climatic variables, these variables did not appear to be good predictors of ground beetle species distribution. The poor model performance appears to be related to the coarse nature of the response and predictor data sets and the absence of key predictors from the models.

Regional IUCN Red Listing: the Process as Applied to Birds in the United Kingdom

Abstract: : The World Conservation Union (IUCN) has developed guidelines that enable the assessment of extinction risk at a regional scale. We used these guidelines to assess the extinction risk of birds in the United Kingdom for comparison with an existing assessment of conservation status. Sixty-four species were categorized as regionally threatened, of which 12 were critically endangered. The categorizations of the 223 species assessed agreed broadly with those from the existing U.K. system, which considers more than extinction risk, thus giving a more complete assessment of conservation status. There was, however, a tendency for the IUCN process to give higher risk status to edge-of-range species (some of which are relatively recent colonists considered of comparatively low conservation concern) and low status to those that have declined substantially but remain common (such as many farmland birds, the focus of considerable conservation effort in the United Kingdom). The final red list depended heavily on the subjective decisions made during the assessment process. An alternative interpretation of the guidelines could have resulted in as many as 19 or as few as 6 species being listed as critically endangered. We recommend the revision of the IUCN guidelines to reduce this subjectivity, in particular with respect to the effect of extralimital populations on the likelihood of regional extinction, and hence the potential for variation in the manner of application between regional red-list assessors. Preventing extinction does not have to be the principal driving force behind conservation action at a regional scale if the continuance of a species is safeguarded in other regions. Resumen: La Union Mundial para la Conservacion (IUCN) ha desarrollado directrices que permiten la evaluacion del riesgo de extincion a escala regional. Utilizamos estas directrices para evaluar el riesgo de extincion de aves en el Reino Unido para compararlas con una evaluacion existente del estatus de conservacion. Sesenta y cuatro especies fueron catalogadas como amenazadas regionalmente, de las cuales 12 estaban en peligro critico. Las categorizaciones de las 223 especies evaluadas en su mayoria coincidieron con las del sistema existente, que considera mas que el riesgo de extincion, por lo tanto proporciona una evaluacion mas completa del estatus de conservacion. Sin embargo, en el proceso de la IUCN hubo una tendencia a proporcionar mayor estatus de riesgo a especies en el borde de su distribucion (algunas de las cuales son colonizadoras relativamente recientes consideradas comparativamente como de bajo interes de conservacion) y menor estatus a aquellas que han declinado sustancialmente pero permanecen comunes (como muchas aves de zonas agricolas, el foco de atencion de muchos esfuerzos de conservacion en el Reino Unido). La lista roja final dependio en buena medida de las decisiones subjetivas que se tomaron durante el proceso de evaluacion. Una interpretacion alternativa de las directrices pudo haber resultado en tantas como 19 o tan solo 6 especies enlistadas como en peligro critico. Recomendamos la revision de las directrices de la IUCN para reducir esta subjetividad, particularmente en relacion con el efecto de poblaciones afuera de sus limites sobre la probabilidad de extincion regional, y por lo tanto sobre el potencial de variacion en la forma de aplicacion por los evaluadores de listas rojas regionales. La prevencion de la extincion no tiene que ser la fuerza de conduccion de acciones de conservacion a escala regional si la persistencia de una especies esta salvaguardad en otras regiones.

Monitoring Important Bird Areas in Africa: Towards a Sustainable and Scaleable System

Abstract: The need for effective global monitoring of biodiversity is clearer than ever, but our measurements remain patchy and inadequate. In the biodiversity-rich tropics, a central problem is the sustainability of monitoring schemes. Locally-based, participatory approaches show promise in overcoming this problem, but may not contribute effectively to monitoring at larger scales. BirdLife International’s framework for monitoring Important Bird Areas (IBAs) in Africa is designed to be simple, robust and locally-grounded, but to produce scaleable results that can be compiled into national or regional indices. Focusing on key sites for bird conservation, identified according to standard criteria, the framework institutionalises monitoring in site management authorities and Site Support Groups (community-based organisations of local people working for conservation and sustainable development). A small, central monitoring unit co-ordinates the programme nationally, compiles, analyses and manages data, and provides feedback. ‘Basic’ monitoring (taking place at all sites) involves scoring of state, pressure and response trends using site information submitted on simple forms. ‘Detailed’ monitoring (taking place at a selected sub-set of sites) involves more intensive measurement of particular variables that relate to site management targets. IBA monitoring is now underway in at least 10 African countries, with implementation of the framework most advanced (thanks to a pilot project) in Kenya. The 2004 IBA monitoring report for Kenya provides extensive information on individual IBAs, plus indices for national trends in state, pressure and response, based on data from 49 out of 60 sites. The experience in Kenya shows that institutionalisation is vital, but takes considerable time and effort; that adequate co-ordination (including timely feedback) is key; and that participatory monitoring has many valuable benefits beyond the data collected. Further work is being undertaken to refine the process, improve its scientific underpinning, and strengthen the feedback loop from data and analysis to action on the ground.

Behaviour, home‐range size and habitat use by male Great Bittern Botaurus stellaris in Britain

Abstract: This paper describes the first use of radiotracking to follow closely the secretive Great Bittern Botaurus stellaris, and to quantify its reedbed habitat preferences at a fine scale Eight males were tracked at two sites in Britain, at which they were mainly resident through the winter Their median home-range sizes were 146, 193 and 331 ha during the booming, moult and winter periods, respectively, and home-ranges were, on average, composed of 30% open pools and 48% reedbed edge (of 30 m width) Great Bitterns were most often active in reed with 20 cm water depth within the 30-m reed edge next to water, whereas areas of reedbed near scrub or further from the water's edge were avoided Reed edge adjacent to open pools was preferred over that adjacent to channels and ditches These results provide a basis for conservation recommendations on the quantity and composition of reedbed habitat and provide the scientific basis for a national programme of reedbed rehabilitation and restoration

Characterization of moorland vegetation and the prediction of bird abundance using remote sensing

Abstract: Aims To characterize and identify upland vegetation composition and height from a satellite image, and assess whether the resulting vegetation maps are accurate enough for predictions of bird abundance. Location South-east Scotland, UK. Methods Fine-taxa vegetation data collected using point samples were used for a supervised classification of a Landsat 7 image, while linear regression was used to model vegetation height over the same image. Generalized linear models describing bird abundance were developed using field-collected bird and vegetation data. The satellite-derived vegetation data were substituted into these models and efficacy was examined. Results The accuracy of the classification was tested over both the training and a set of test plots, and showed that more common vegetation types could be predicted accurately. Attempts to estimate the heights of both dwarf shrub and graminoid vegetation from satellite data produced significant, but weak, correlations between observed and predicted height. When these outputs were used in bird abundance–habitat models, bird abundance predicted using satellite-derived vegetation data was very similar to that obtained when the field-collected data were used for one bird species, but poor estimates of vegetation height produced from the satellite data resulted in a poor abundance prediction for another. Conclusions This pilot study suggests that it is possible to identify moorland vegetation to a fine-taxa level using point samples, and that it may be possible to derive information on vegetation height, although more appropriate field-collected data are needed to examine this further. While remote sensing may have limitations compared with relatively fine-scale fieldwork, when used at relatively large scales and in conjunction with robust bird abundance–habitat association models, it may facilitate the mapping of moorland bird abundance across large areas.

Timing of shedding seeds and cones, and production in different stands of Scots pines at Abernethy Forest, Scotland

Abstract: Summary A study was carried out over 11 seed years on the timing of shedding of seeds and cones, and annual seed fall and cone production in three stands of native Scots pinewood and a Scots pine plantation in Abernethy Forest, Scotland. Peaks in seed fall took place mainly in May, and cones were shed mainly between June and August. There were few residual seeds remaining in shed cones. Synchronized peaks in seed fall and cone production (mast years) took place at 3-year intervals across the different stands. The difference between cohorts of high and low cone production ranged from factors of 5 to 20 among sites. Coeffi cients of variation for cone production ranged from 62 to 84 per cent among sites. There were no signifi cant differences in cone production among sites, but there were site-related differences in seed fall. The larger canopy cover in the plantation probably accounted for the higher seed fall per square metre there, though variations in the amount of seed eaten by birds and mammals may also have been important. Canopy cover needs to be considered when converting cone densities under crowns to cone density per unit of woodland area. A similar calculation is diffi cult for seeds because they are lighter than cones and many fall outside the area under the crowns. The results are discussed in relation to the potential for tree regeneration and the availability of food for birds and mammals prior to seed dispersal.

Productivity of White-Tailed Tropicbird on Aride Island, Seychelles

Abstract: Nine years (1989/90-2002) of data on a asynchronous pelagic seabird, the White-tailed Tropicbird (Phaethon lepturus), breeding on Aride Island, Seychelles, were used to examine: (1) annual variation in productivity and, (2) the importance of large scale (El Nino Southern Oscillation) factors in explaining productivity levels. In 2001 and 2002, we examined the influence of local scale factors (parasitism by hard ticks Amblyomma loculosum and intra- and inter-specific competition for nest-sites) on productivity. Productivity between years only ranged from 0.21 to 0.37 chicks/breeding pair, but it was nevertheless significantly and inversely correlated with the El Nino index. No influence on productivity was caused by local factors. The frequency distribution of chick deaths varied significantly with chick age in 2001 but not in 2002. Most of the chick deaths were from starvation, in particular for chicks older than 20 days. As opposed to synchronous seabird species, there were no years with total b...

Decline of the Orkney Hen Harrier Circus cyaneus population: Do changes to demographic parameters and mating system fit a declining food hypothesis?

Abstract: Capsule A decline in polygyny and lower secondary female breeding success have reduced male productivity and most likely led to the population decline. Aims To examine whether changes in demographic parameters during a population decline fit with a hypothesis that there has been a reduction in food supplies. Methods We examined changes in the number of young, numbers of successful broods and the size of these broods, produced on west Mainland, Orkney between 1953 and 2000 from ringing returns and original nest records. We also examined the changes in polygyny levels between 1967–74, 1976–81 and 1998–2000. Using more intensive data from 1980–81 and 1998–2000, we examined whether there were any changes in various breeding parameters of primary (monogamous or alpha) females or secondary (beta) females. Results Numbers of young and broods produced have declined dramatically in the west Mainland of Orkney since the end of the 1970s. In the 1970s, an average of 60 chicks fledged each year, whereas an average of...