Identifying the drivers of population change is a key part of the conservation process, as it provides an evidence-based focus for conservation efforts. Recent research by the BTO has brought together data from several volunteer-based surveys to model the demographic drivers of population change for a suite of common bird species. This approach also delivers a powerful method that can be applied to rarer species, for which data are less readily available. Drivers of avian population change: volunteer-based surveys allow an innovative integrated approach Identifying the drivers of population change is a key component of the conservation process, since it allows scientists, managers and policymakers to devise ways of addressing problems and reversing declines. BTO-led work has documented bird population changes across key groups, from farmland birds to waterbirds, over several decades. Bird populations are generally affected by one of three main processes: the number of breeding individuals surviving from one year to the next, the number of chicks fledging and surviving to breeding age, and immigration and emigration of individuals into and out of the area concerned. A novel approach to modelling Previous research has often focused on only one aspect of the possible demographic drivers, but a recent study by the BTO (Robinson et al. 2014) used long-term data (18-46 years) drawn from a number of BTO-led volunteer surveys (, Breeding Bird Survey, Nest Record Scheme and bird ringing), to model the demographic drivers of population trends for 17 common avian species. The novelty of this study was in its use of an integrated approach, as well as the inclusion of a parameter to account for potential processes that were not measured directly, such as the number of nesting attempts. An example was provided by two declining species, Lapwing and Song Thrush, for which population drivers were identified as changes in juvenile survival and reproductive success, respectively. Both of these species were “Red-listed” in the most recent Birds of Conservation Concern report to which BTO data contributed. First-year survival is key Overall results showed that the population dynamics of declining species are driven mainly by the recruitment of individuals to the breeding population, which is particularly influenced by the survival of birds during their first year. For non-declining species, adult survival is the main factor driving population trends. In policy terms, this suggests that measures aimed at improving overwinter survival, such as increasing the food available to farmland birds at the end of winter to avoid the “hungry gap”, are likely to be more effective than measures taken during the breeding season. The application of this novel method to conservation This research demonstrates the importance of an integrated approach to identifying key demographic parameters, as well as the crucial role of volunteer-based monitoring programmes. An important application of this method is that it allows factors that could affect scarcer species, for which data are more limited, to be inferred. This enables the early implementation of targeted conservation measures for species that are difficult to monitor, thereby improving the effectiveness of evidence-based conservation strategies. BTO has access to unparalleled amounts and diversity of volunteer-collected avian data, and has the expertise to analyse them. If you would like to take part in one of our surveys, you too could contribute to our datasets.

British moorland can support important populations of breeding waders, gamebirds and birds of prey, underlining its conservation value. Moorland and associated habitats are a result of management, in particular for sheep grazing and sport shooting of Red Grouse. Moorland conservation may additionally be shaped by financial payments made through agri-environment or similar schemes, using management prescriptions to maintain, restore or enhance particular components. While a suite of such prescriptions have been taken up quite widely, an ongoing decline of moorland birds is amongst the more marked results of the 2007-11 Bird Atlas. BTO researchers, with collaborators from ADAS UK and the former Scottish Coal, have just reported on a ten-year monitoring programme set up to examine the effectiveness of moorland management in south-west Scotland. Management prescriptions advocated widely as best practice for moorland birds began at the site within the Muirkirk and North Lowther Uplands SPA (Special Protection Area) in 2002. These included including muirburn and cutting, grazing, legal predator control and the restoration of hydrological features. Annual surveys of vegetation and birds were carried out to assess responses to these prescriptions. For birds, comparisons were made against trends for moorland habitats derived from the Breeding Bird Survey (BBS), which accounted for factors such as weather that have a marked effect on moorland bird populations. The expectation that the breeding bird community would increase in response to the management prescriptions adopted was not fulfilled. Only two species increased relative to the general trend for moorland and one of them was Carrion Crow, a species that was being actively removed as part of predation control measures. Most species showed no change or actually declined. Although the responses by vegetation to changes in grazing were quite small, moorland habitat condition did appear to have stabilized and further degradation halted. More relevant, however, was that declines in populations were common across species with different habitat associations, and so a causal relationship with the management changes appeared unlikely. Similarly an effect of disturbance was unlikely, but it remained plausible that the failure to effectively control predators could have contributed to the failure to achieve the principal objective of increasing breeding bird populations. Although based on monitoring the effects of management prescriptions rather than a controlled experimental design, this work highlights the difficulties in establishing effective management regimes for the benefit of moorland birds. It also underlines a need to develop an improved understanding of the factors that shape moorland bird communities more widely. Raising the question as to whether moorland bird conservation can be effective where they remain vulnerable to predation, it will contribute towards the wider debate on the future of British uplands.