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Most European goose populations have increased exponentially, and this has increasingly brought them into conflict with human activities. To manage this conflict, we used multi-criteria decision analysis to help set population targets for a super-abundant population of greylag geese (Anser anser). We relied on expert elicitation to assess the consequences of varying goose abundance on nine ecological, economic, and societal objectives. Representatives from national governments and from non-governmental organizations then weighted the objectives based on their perceived relative importance, and we used a consensus-convergence model to reach stakeholder agreement on the tradeoffs among objectives. The preferred population targets for two management units represent about a 20% reduction from current abundances, which from a management perspective would require considerable effort above and beyond current population-control measures. We believe that multi-criteria decision analysis can provide a systematic and transparent framework for building consensus among diverse stakeholders in a wide array of human-wildlife conflicts.

The population of barnacle geese wintering in Denmark has shown a steep increase during the last decades, prompting a parallel escalation of agricultural conflicts. In Denmark, economic compensation to farmers suffering goose damage to crops is not practiced, but despite that the barnacle goose is fully protected, landowners can obtain a permit to undertake so-called derogation shooting (lethal scaring) to reduce local damage to agricultural crops where other means of scaring have been insufficient. Here, we describe the development in numbers and derogation efforts of barnacle geese in Denmark in the period 2010/11 – 2018/19. We demonstrate that differences in the number of issued derogation permits across the country is primarily explained by differences in barnacle goose abundance, and secondarily, by prevalence of vulnerable crops and differences in crop productivity. Hence, derogation efforts are highest in areas with many geese, high proportions of crops vulnerable to goose grazing and high crop yields. Our analysis indicates that the level of conflict, and probably the economic impact of affected farmers, is proportional to the abundance of geese present locally. While the increasing derogation shooting may be a temporary solution to individual farmers, current unorganised practice might only redistribute geese locally and increase energy demands of the affected birds. Currently, there is a lack of alternative and undisturbed accommodation areas in the Danish agricultural landscape for the displacement of geese to achieve a satisfactory effect of derogation shooting.

Over-summering within or near the African wintering range by immature, non-breeding individuals occurs regularly in several species of long-distance migratory raptors, yet the extent of over-summering in Africa by adult birds remains unclear. In this study, we describe a case of an adult Montagu's Harrier over-summering in Africa, as revealed by GPS tracking. By relating detailed knowledge of the bird's movements to remotely sensed environmental data (normalized difference vegetation index, NDVI), we show that over-summering in this case was likely related to an exceptionally difficult breeding season the previous year rather than an effect of adverse weather conditions encountered during the winter or a failed attempt to migrate. Various factors are discussed as potential driving forces behind the bird's intra-African movements. Finally, we relate the documented case to a large number of North European Montagu's Harriers studied by telemetry and show that over-summering in Africa by adult individuals is indeed a rare event.

The Danish breeding Starling population declined at a mean annual rate of −2.24% ± 0.39 (95% CI) during 1976–2015 (a 60% decline overall). Starling density in the mid-1990s was positively correlated with dairy cattle abundance in 13 local areas. Regional declines in Starling abundance between 2001 and 2014 were positively correlated with loss of high intensity grazing pressure by dairy cattle, as more animal husbandry moved indoors. The long-term decline in national Starling abundance was positively correlated with the long term numbers of dairy cattle grazing outdoors. This study therefore confirms that not only does the extent of available grassland to breeding Starlings affect their relative abundance, but that the intensity of grazing of these grasslands is also of importance.

Evidence of declines in insect populations has recently received considerable scientific and societal attention. However, the lack of long-term insect monitoring makes it difficult to assess whether declines are geographically widespread. By contrast, bird populations are well monitored and often used as indicators of environmental change. We compared the population trends of European insectivorous birds with those of other birds to assess whether patterns in bird population trends were consistent with declines of insects. We further examined whether declines were evident for insectivores with different habitats, foraging strata, and other ecological preferences. Bird population trends were estimated for Europe (1990-2015) and Denmark (1990-2016). On average, insectivores declined over the study period (13% across Europe and 28% in Denmark), whereas omnivores had stable populations. Seedeaters also declined (28% across Europe; 34% in Denmark), but this assessment was based on fewer species than for other groups. The effects of insectivory were stronger for farmland species (especially grassland species), for ground feeders, and for cold-adapted species. Insectivory was associated with long-distance migration, which was also linked to population declines. However, many insectivores had stable populations, especially habitat generalists. Our findings suggest that the decline of insectivores is primarily associated with agricultural intensification and loss of grassland habitat. The loss of both seed and insect specialists indicates an overall trend toward bird communities dominated by diet generalists.Declinaciones a Largo Plazo de Poblaciones de Aves Insectívoras en Europa y las Causas Probables Resumen La evidencia de las declinaciones poblacionales de insectos ha recibido recientemente una atención considerable por parte de la comunidad científica y la sociedad. Sin embargo, la falta de un monitoreo prolongado de los insectos complica valorar si estas declinaciones tienen una distribución extensa geográficamente. Como contraste, las poblaciones de aves tienen un monitoreo constante y con frecuencia se usan como indicadores del cambio climático. Comparamos las tendencias poblacionales de las aves insectívoras de Europa con las de otras aves para valorar si los patrones en las tendencias poblacionales de aves son consistentes con las declinaciones de insectos. Además examinamos si las declinaciones eran evidentes para aves insectívoras con diferentes hábitats, estratos de alimentación, y otras preferencias ecológicas. Las tendencias poblacionales de las aves se estimaron para Europa (1990 - 2015) y para Dinamarca (1990 - 2016). En promedio, las aves insectívoras declinaron a lo largo del periodo de estudio (13% en Europa y 28% en Dinamarca) mientras que las aves omnívoras tuvieron poblaciones estables. Las poblaciones de aves que se alimentan de semillas también declinaron (28% en Europa; 34% en Dinamarca), pero esta valoración se basó en menos especies que para los otros grupos. Los efectos de la insectivoría fueron más evidentes para las especies de tierras agrícolas (especialmente las especies de pastizales), para las especies que se alimentan sobre el suelo y para las especies adaptadas al frío. La insectivoría estuvo asociada con la migración de larga distancia, la cual también estuvo ligada a las declinaciones poblacionales. Sin embargo, muchas aves insectívoras tuvieron poblaciones estables, especialmente aquellas generalistas de hábitat. Nuestros hallazgos sugieren que la declinación de las aves insectívoras está asociada principalmente con la intensificación agrícola y la pérdida de pastizales. La pérdida de aves cuya alimentación es especialista en insectos o en semillas indica una tendencia general hacia comunidades de aves dominadas por aquellas con dietas generalistas.

Harvest records are often assumed to offer an indirect measure of population abundance in huntable species. However, this requires population density changes are reflected in comparable linear changes in harvest rates. We tested this assumption for common snipe Gallinago gallinago, common wood pigeon Columba palumbus, coot Fulica atra, grey partridge Perdix perdix, roe deer Capreolus capreolus and brown hare Lepus europaeus in Denmark. If we consider hunting a form of predator-prey interaction, the annual kill can be viewed as a predator functional response to prey population size. Convergence of the annual kill to a type I functional response with similar auto-correlative structures in the harvest and count data would support the hypothesis that fluctuations in harvest and population abundance occurred with similar periodicity. The annual kill of common snipe showed the best fit to a type I functional response to the point count indices, with similar auto-correlative structures in the two variables. Other species showed different functional responses, the result of hunter behaviour, such as voluntary hunting restraint on species of concern and saturation effects from rapidly expanding abundant species. Relationships between the annual kill and population abundance were complex and incorporation of hunting legislation changes improved optimal model fits between harvest statistics and count data. Consideration of the validity of the underlying assumptions is necessary before harvest records are used as an index for population size. It is essential that detectability/accessibility of a species does not change systematically over time. Such bias may derive from habitat shifts, difference in timing of counts and hunting harvest, changes in migration patterns and annual reproduction and mortality. We recommend the continued collation of hunting harvest statistics, supported by sociological studies, to provide insight into the mechanisms that affect the hunting effort, to understand relationships between harvest statistics and population abundance.

Long-distance migrants are particularly recognized for the distances covered on migration, yet little is known about the distances they cover during the rest of the year. GPS-tracks of 29 Montagu's harriers from breeding areas in France, The Netherlands and Denmark showed that harriers fly between 35 653 and 88 049 km yr −1 , of which on average only 28.5% is on migration. Mean daily distances during migration were 296 km d −1 in autumn and 252 km d −1 in spring. Surprisingly, males' daily distances during breeding (217 km d −1 ) were close to those during migration, whereas breeding females moved significantly less (101 km d −1 ) than males. In terms of flight distance, the breeding season seemed nearly as demanding as migration periods for males. During the six winter months, both sexes moved less (114 and 128 km d −1 for females and males, respectively) than during migration. Harriers therefore covered shorter daily distances during winter which might allow birds to compensate for the more demanding phases of migration and breeding.

The abundant and widespread Common Starling (Sturnus vulgaris) is currently declining across much of Europe due to landscape changes caused by agricultural intensification. The proximate mechanisms causing adverse effects to breeding Starlings are unclear, hampering our ability to implement cost-efficient agri-environmental schemes to restore populations to former levels. This study aimed to show how this central foraging farmland bird uses and selects land cover types in general and how use of foraging habitat changes in relation to distance from the nest. We attached GPS-loggers to 17 breeding Starlings at a Danish dairy cattle farm in 2015 and 2016 and analysed their use of different land cover types as a function of distance intervals from the nest and their relative availability. As expected for a central place forager, Starlings increasingly avoided potential foraging areas with greater distance-to-nest: areas ≥ 500 m were selected > 100 times less frequently than areas within 100 m. On average, Starlings selected the land cover category Grazed most frequently, followed by Short Grass, Bare Ground, Meadow and Winter Crops. Starlings compensated for elevated travel costs by showing increasing habitat selection the further they foraged from the nest. Our results highlight the importance of Grazed foraging habitats close to the nest site of breeding Starlings. The ecological capacity of intensively managed farmlands for insectivorous birds like the Starling is decreasing through conversion of the most strongly selected land cover type (Grazed) to the least selected (Winter Crops) which may be further exacerbated through spatial segregation of foraging and breeding habitats.

It has recently been stated that the global goal of halting the loss of biodiversity by 2010 has not been met highlighting the urgent need to monitor trends in biodiversity. Our study suggests that existing indicators of bird biodiversity in Denmark are inaccurate and we present a new objective method for accurately assessing trends in specific habitats using common bird species. Bird species were selected for creating habitat specific indicators by calculating their relative habitat use (RHU) in nine different habitat categories. RHU indicates the degree to which a habitat is preferred (RHU > 2) or avoided (RHU 2 and revealed that existing habitat indicators, based on species lists from the Pan-European Common Bird Monitoring Scheme (PECBMS), often included species that did not in fact have preferences for those particular habitats in Denmark. Habitat specific indicators based on the new species selection method showed significant negative trends in three of nine habitat categories: coniferous forest, bog/marsh and heath. Habitat classes were further combined to create overall indicators for forest, farmland and freshwater. A comparison of these indicators with the existing indicators revealed a negative overall trend for forest habitat, which had previously been overlooked, suggesting that species selection is crucial for the development of informative indicators. The habitat specific farmland indicator confirmed the negative trend in the current farmland indicator. The methodology for indicator species selection presented here could potentially be applied for use in a global context for a wider range of taxonomic groups.

Corn buntings Miliaria calandra were abundant throughout arable agricultural landscapes in Europe, but have catastrophically declined since the mid 1970s with changes in farming practice and now give serious conservation cause for concern. Corn buntings declined in Denmark during 1976-1993, but (almost unique in Europe) have since increased (by up to 11% per annum) in some areas without specific conservation recovery actions. Based on breeding bird surveys in the mid 1990s, highest corn bunting densities occurred on mixed agriculture in west Denmark (Jylland); the species was rarer or absent in regions of highest arable land cover. Corn bunting density and extent of rotational and permanent grassland were correlated, but not with spring sown barley (all known to constitute important corn bunting winter habitat). The extent of spring barley rapidly declined in Denmark during the 1980s, but since 1990, most counties have since shown 2-3% annual increases in this crop, except in Nordjylland, where high densities of corn buntings have remained stable. Elsewhere in Jylland, corn buntings have increased in counties supporting highest densities during the mid 1990s, contrasting stable or declining trends in south and east Denmark where densities were originally lower. After dramatic decreases everywhere in Denmark, corn buntings retain highest breeding densities associated with mixed agriculture, especially where grassland and spring sown barley remained in greatest extent. Although purely based on land use correlation and bird surveillance, these results show an association between mixed farming and favourable conservation status of a species now red-listed throughout much of Europe. Further investigations of habitat use at small spatial scales and throughout the annual cycle are urgently required to better enlighten specific recommendations for wider applicability of guidelines for corn bunting recovery actions elsewhere.